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Estimating the Economic Cost of One of the World's Major Insect Pests, Plutella xylostella (Lepidoptera: Plutellidae): Just How Long Is a Piece of String?

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Since 1993, the annual worldwide cost of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), control has been routinely quoted to be US$1 billion. This estimate requires updating and incorporation of yield losses to reflect current total costs of the pest to the world economy. We present an analysis that estimates what the present costs are likely to be based on a set of necessary, but reasoned, assumptions. We use an existing climate driven model for diamondback moth distribution and abundance, the Food and Agriculture Organization country Brassica crop production data and various management scenarios to bracket the cost estimates. The "length of the string" is somewhere between US$1.3 billion and US$2.3 billion based on management costs. However, if residual pest damage is included then the cost estimates will be even higher; a conservative estimate of 5% diamondback moth-induced yield loss to all crops adds another US$2.7 billion to the total costs associated with the pest. A conservative estimate of total costs associated with diamondback moth management is thus US$4 billion-US$5 billion. The lower bound represents rational decision making by pest managers based on diamondback moth abundance driven by climate only. The upper estimate is due to the more normal practice of weekly insecticide application to vegetable crops and the assumption that canola (Brassica napus L.) is treated with insecticide at least once during the crop cycle. Readers can decide for themselves what the real cost is likely to be because we provide country data for further interpretation. Our analysis suggests that greater efforts at implementation of even basic integrated pest management would reduce insecticide inputs considerably, reducing negative environmental impacts and saving many hundreds of millions of dollars annually.
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Estimating the Economic Cost of One of the World's Major Insect
Pests, Plutella xylostella (Lepidoptera: Plutellidae): Just How Long
is a Piece of String?
Author(s): Myron P. Zalucki, Asad Shabbir, Rehan Silva, David Adamson, Liu Shu-
Sheng, and Michael J. Furlong
Source: Journal of Economic Entomology, 105(4):1115-1129. 2012.
Published By: Entomological Society of America
DOI: http://dx.doi.org/10.1603/EC12107
URL: http://www.bioone.org/doi/full/10.1603/EC12107
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FORUM
Estimating the Economic Cost of One of the World’s Major Insect
Pests, Plutella xylostella (Lepidoptera: Plutellidae): Just How Long
Is a Piece of String?
MYRON P. ZALUCKI,
1
ASAD SHABBIR,
2
REHAN SILVA,
1
DAVID ADAMSON,
3
LIU SHU-SHENG,
4
AND MICHAEL J. FURLONG
1,5
J. Econ. Entomol. 105(4): 1115Ð1129 (2012); DOI: http://dx.doi.org/10.1603/EC12107
ABSTRACT Since 1993, the annual worldwide cost of diamondback moth, Plutella xylostella (L.)
(Lepidoptera: Plutellidae), control has been routinely quoted to be US$1 billion. This estimate
requires updating and incorporation of yield losses to reßect current total costs of the pest to the world
economy. We present an analysis that estimates what the present costs are likely to be based on a set
of necessary, but reasoned, assumptions. We use an existing climate driven model for diamondback
moth distribution and abundance, the Food and Agriculture Organization country Brassica crop
production data and various management scenarios to bracket the cost estimates. The length of the
stringis somewhere between US$1.3 billion and US$2.3 billion based on management costs. However,
if residual pest damage is included then the cost estimates will be even higher; a conservative estimate
of 5% diamondback mothÐinduced yield loss to all crops adds another US$2.7 billion to the total costs
associated with the pest. A conservative estimate of total costs associated with diamondback moth
management is thus US$4 billionÐUS$5 billion. The lower bound represents rational decision making
by pest managers based on diamondback moth abundance driven by climate only. The upper estimate
is due to the more normal practice of weekly insecticide application to vegetable crops and the
assumption that canola (Brassica napus L.) is treated with insecticide at least once during the crop
cycle. Readers can decide for themselves what the real cost is likely to be because we provide country
data for further interpretation. Our analysis suggests that greater efforts at implementation of even
basic integrated pest management would reduce insecticide inputs considerably, reducing negative
environmental impacts and saving many hundreds of millions of dollars annually.
KEY WORDS bioclimatic modeling, cost of management, pest control, diamondback moth, inte-
grated pest management
Entomologists are notorious for conjuring monetary
values to ascribe to pest problems when emphasizing
the importance of a given pest in a scientiÞc paper or
justifying grant applications to sanction research to
address the issue. The diamondback moth, Plutella
xylostella (L.) (Lepidoptera: Plutellidae) is, at Þrst
glance, different. Ever since Talekar and Shelton
(1993) published their landmark review, the annual
cost of diamondback moth control to the world econ-
omy has been cited as US$1 billion by pretty much
everyone writing a paper on diamondback moth, and
no doubt when applying for grant funds. Interestingly
the Þgure has not changed since 1993, even with in-
ßation and increased production of Brassica hosts,
particularly canola (Brassica napus L.). Perhaps pest
management has become more efÞcient after all or
maybe the original estimate was hyperbole? The Þg-
ure itself was not calculated by Talekar and Shelton
(1993) but was taken from a short foreword to the
Proceedings of the Second International Workshop on
Diamondback Moth and other Crucifer Pests (Talekar
1992) in which Javier (1992) suggested that control
could cost approximately U.S. $1 billion annually,but
provided no justiÞcation for the estimate.
Here, we present a detailed basis for estimating the
worldwide control costs of diamondback moth. Our
aim is to outline a transparent methodology for arriv-
ing at a justiÞable value that can be readily updated
over time and that could be applied to other cropÐpest
systems. The need for such a monetary value can be
justiÞed on a number of dry economic rationalist
grounds quite apart from its necessity for grant appli-
cations and the introductions to scientiÞc manu-
scripts. Ultimately, applied research needs to redress
major constraints to food security and so, of the myriad
1
School of Biological Sciences, The University of Queensland,
Brisbane, Australia, 4072.
2
School of Agriculture and Food Sciences, The University of
Queensland, Brisbane, Australia, 4072.
3
Risk and Sustainable Management Group, School of Economics,
The University of Queensland, Brisbane, Australia, 4072.
4
Institute of Insect Sciences, College of Agriculture and Biotech-
nology, Zhejiang University, Hangzhou, PeopleÕs Republic of China.
5
Corresponding author, e-mail: m.furlong@uq.edu.au.
0022-0493/12/1115Ð1129$04.00/0 2012 Entomological Society of America
of competing interests, how do we objectively com-
pare which pests are major constraints and justify
research effort and allied expenditure? So that valid
comparisons can be made, the inevitable assumptions
must be justiÞed and the methodology that is applied
needs to be transparent.
To estimate the total cost of diamondback moth to
Brassica crop production and management, we re-
quire some knowledge of how much is spent per ha of
diamondback moth host plant (Brassica crop) pro-
duction on diamondback moth management and how
much production is lost despite this management.
These costs will depend in part on where diamond-
back moth is found (abundance varies geographi-
cally), how abundance is distributed relative to agri-
cultural host plants and how much economic damage
diamondback moth feeding inßicts on crops. None of
these questions is easy to answer. Despite being such
a major pest of crucifers (since 1985 six international
workshops or conferences have been devoted to the
pest (Talekar and Griggs 1986, Talekar 1992, Sivapra-
gasam et al. 1997, Endersby and Ridland 2004, Shelton
et al. 2008, Srinivasan et al. 2011) and being, perhaps,
the most widely distributed lepidopteran species, our
understanding of the geographic distribution and
abundance of diamondback moth is limited to course
scale and probably incorrect maps. The original Com-
monwealth Institute of Entomology map for diamond-
back moth (Commonwealth Institute of Entomology
1967) is an amalgam of incomplete distribution records
and imagination (see Zalucki and Furlong 2008),
whereas more recent CAB maps just show a dot in a
whole country if the species is recorded (CAB 2012)!
First, we present a way to estimate, albeit crudely, the
distribution and abundance of diamondback moth glob-
ally. Next, we estimate a relationship between the suit-
ability of a location for diamondback moth and the at-
tendant pest management costs and, assuming the world
is rational, insecticides are only applied when pest levels
warrant control. We then use the production data for
each country to bracket the likely costs given certain
assumptions. The brackets will necessarily be wide and
the piece of stringis of variable length between these
brackets!
Methods
Estimating the Distribution Of Diamondback Moth
Abundance. Zalucki and Furlong (2008, 2011) devel-
oped a CLIMEX model (Sutherst and Maywald 2004)
for diamondback moth that can be used to predict its
geographic distribution and relative abundance, its
seasonal phenology across its distribution range, and
even long-term variations in abundance; see Zalucki
and Furlong (2005) for details of the approach. The
rationale under pinning CLIMEX has been described
many times (Yonow and Sutherst 1998, Zalucki and
Furlong 2008, Li et al. 2012), but we outline the ap-
proach brießy for readers not yet familiar with the
methodology.
CLIMEX calculates a growth index (GI), analogous
to population growth rate, that describes the potential
of the population to increase at a location. The growth
index, calculated weekly, is a product of temperature
(TI) and moisture (MI) indices. For calculation of
both TI and MI, there is a range of conditions of
temperature and moisture over which growth is max-
imal. Either side of the optimum range growth rate
decreases. Above some upper threshold and below a
lower threshold growth ceases. These thresholds de-
Þne the biological parameters for a species and need
to be estimated (see, e.g., Zalucki and van Klinken
2006).
A measure of the relative suitability of a location for
a species to persist is summarized in a single annual
eco-climatic index (EI), scaled to 100: EI 100
GI/52 SI SX, where 52 is the number of weeks in
a year; SI are four stress indices, describing the species
response to the extremes of cold (CS, cold stress), heat
(HS), dry (DS), and wet (WS) conditions; and SX, if
needed, are interactions between extreme conditions;
cold-dry (CDS), cold-wet (CWS), hot-dry (HDS),
and hot-wet (HWS) stresses. The stress indices (SI
and SX) are accumulated at a speciÞed rate whenever
conditions exceed a speciÞed threshold.
Indices are calculated weekly for each location us-
ing standard meteorological data; a locationÕs long-
term monthly average maximum and minimum tem-
peratures, rainfall, and humidity. Areas with positive
values for EI are suitable for species persistence; the
larger the value of EI, the more suitable the location.
Generally, an EI of 15Ð20 would be considered mar-
ginal for a speciesÕ long-term persistence at a location.
The values for parameters that describe the TI and MI
components of growth, and the various stress indices
(SI) and their interactions (SX), can be estimated
from laboratory or Þeld studies (Zalucki and van
Klinken 2006).
Unknown or poorly measured values are estimated
by an iterative procedure that involves comparing the
predicted geographic distribution with the actual dis-
tribution and adjusting parameter values. Comparing
the predicted and observed species distribution in an
area (e.g., a continent) not used for the procedure can
test the parameter tuning; see Maywald and Sutherst
(1991) for details. This is one independent test of the
model and can be contrasted with the more commonly
used procedure of randomlysubsampling from a
current geographic distribution to both Þt and test
various empirical GIS models (e.g., as is done with
MAXENT or similar), but of course comparisons
across continents is only applicable if a species is
widespread.
The CLIMEX model for diamondback moth in Za-
lucki and Furlong (2008) was initially developed using
the anecdotal distribution data in Commonwealth In-
stitute of Entomology maps (Commonwealth Institute
of Entomology 1967), the seasonal prevalence of di-
amondback moth in the Cameron Highlands of Ma-
laysia and published values for various parameters
(Zalucki and Furlong 2008, 2011). There is no distinc-
tion between the growth and development responses
of temperate and tropical diamondback moth popu-
lations to different temperatures (Shirai 2000), and it
1116 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 4
was assumed that all diamondback moth populations
have uniform responses to climatic variables. Most of
the temperature related parameters were derived
from Liu et al. (2002). Zalucki and Furlong (2011)
reÞned the initial model by adjusting the moisture-
related parameters, essentially making the species
more dry tolerant, requiring concomitant adjustments
in the dry and wet stress thresholds and similar
changes for the degree-day accumulation of cold and
heat stress parameters (Zalucki and Furlong 2008,
2011). The model was subsequently tested using dia-
mondback moth damage data from China and areas
predicted to support persistent diamondback moth
populations correlated well with regions reporting the
most severe pest damage (Li et al. 2012).
We present further independent tests of the dia-
mondback moth CLIMEX model by generating sea-
sonal phenologies of the pest at several locations.
These were chosen as data were available, principal
sources were the proceedings of the diamondback
moth and other crucifer pest workshops (Talekar and
Griggs 1986, Talekar 1992, Sivapragasam et al. 1997,
Endersby and Ridland 2004, Shelton et al. 2008, Srini-
vasan et al. 2011). The seasonal phenologies were
derived from data read off graphs or taken from tables
that estimate the seasonal prevalence of diamondback
moth based on counts of immatures in Þelds or adults
in pheromone or light traps (see sources in Fig. 2). We
have expressed the data as the percentage that oc-
curred at each sampling date over a year. These sea-
sonal phenologies use data that were not used to con-
struct the model and therefore represent independent
validation. The predictions are based on the standard
CLIMEX output of weekly GI that indicates the suit-
ability of a time period for diamondback moth popu-
lations, again expressed as a percentage of the total GI.
We are only interested in the general visual concur-
rence of these graphs, as we are not attempting to
make speciÞc predictions of abundance. We present
these tests to further justify the use of the diamond-
back moth-CLIMEX model as a reasonable approxi-
mation to the distribution and abundance of diamond-
back moth, an essential component of the method that
we have developed to estimate how much it costs to
manage this pest.
Estimating the Costs of Diamondback Moth Con-
trol. We establish a relationship between GI for a site
and the application of insecticides for diamondback
moth management by using data from several loca-
tions in the Changjiang River Valley, China, in 2000
and 2001. At each location diamondback moth abun-
dance was assessed over one to two cropping seasons
in experimental cabbage (Brassica oleracea Capitata),
caulißower (B. oleracea Botrytis), and broccoli (B.
oleracea Italica) crops. Within these crops, the num-
ber of insecticide applications required using farmer
practice (FP) or a threshold-based integrated pest
management (IPM) approach was recorded (see Ta-
ble 1 for details). We pool the data to establish the
following broad relationships for insecticide applica-
tions under each management practice.
For FP plots or Þelds, no. of applications 5.6
GI/wk 0.82 (F
1, 9
16.25; P0.003; r
2
adj
0.6). For
IPM plots or Þelds, no. of applications 2.5 GI/
wk 0.06 (F
1, 9
9.84; P0.012; r
2
adj
0.45), where
GI/wk is the average GI over the period the crop was
grown at each location, using climate data from a
nearby location.
In one set of calculations, we assume spray decision
making for Brassica vegetable crops is based on GI as
detailed above. For canola, we assume that crops are
either treated with insecticide once per season or that
crops are treated with insecticide after application of
the same GI-based decision making processes that are
applied to vegetable crops. In tropical countries, it is
not uncommon for Brassica crops to be sprayed
weekly or biweekly (Rauf et al. 2004, Sandur 2004,
Mazlan and Mumford 2005); in our calculations, we
use a single insecticide application per week as the
worst-practice scenario.
We use annual world production statistics
(FAOSTAT 2012) as the basis of calculations. Data are
available for three categories of Brassica crops: cab-
bage and other brassicas (mainly leafy Chinese green
vegetables), caulißower and broccoli, and canola or
oilseed rape. The production area represents the total
Table 1. Field trials used to determine the no. of insecticide applications used in IPM or FP control strategies
Location Crop Date GI/wk
a
No. insecticide
applications
Planting Harvest FP IPM
Song-jiang Cabbage 2 Aug. 2000 8 Nov. 2000 0.49 2 1
Whenzou Cabbage 16 Aug. 2000 25 Oct. 2000 0.85 4 2
Xiao-shan Cabbage 7 Sept. 2000 20 Nov. 2000 0.63 3 1.8
Qiao-si Cabbage 14 Sept. 2000 28 Nov. 2000 0.64 2 1.33
Ningbo Cabbage 17 Sept. 2000 1 Dec. 2000 0.8 4 2
Song-jiang Cabbage 1 Jan. 2000 1 May 2000 0.47 2 0.67
Song-jiang Caulißower 24 Aug. 2001 4 Nov. 2001 0.58 2.3 1
Whenzou Caulißower 30 Aug. 2001 15 Nov. 2001 0.57 2.3 1.67
Xiao-shan Broccoli 7 Sept. 2001 20 Nov. 2001 0.58 2 1.67
Qiao-si Broccoli 16 Sept. 2001 28 Nov. 2001 0.52 1.3 1.33
Song-jiang Caulißower 17 Sept. 2001 1 Dec. 2001 0.5 3 1.67
a
For each trial the diamondback moth GI accumulated each week during the period in which the crop was growing was computed for use
in regressions (see Materials and Methods).
August 2012 ZALUCKI ET AL.: ECONOMIC COST OF P. xylostella 1117
area of each crop grown in a country per year, and we
calculated the mean production area of each crop for
each country for which data are available from 2000 to
2009, the most up to date data available (FAOSTAT
2012). We assume that all crops take 12 wk from
transplanting or sowing to harvest.
We also assume that if a region is suitable for dia-
mondback moth (GI 15), then we can distribute the
crops proportionally to where diamondback moth is
located and calculate the insecticide costs for each
grid square. CLIMEX outputs a Þle of georeferenced
data that shows the value of selected output variables
for each x-y location or cell on a 30-min grid. We
output EI, GI, weeks GI positive, degree-days, and
number of diamondback moth generations for each
location. We ported these data to ArcView (ESRI
2011) and used country shape Þles to distribute dia-
mondback moth distribution and abundance by coun-
try. This enabled us to link country production area
data for each of the crops to CLIMEX output that
could then be linked to likely control costs based on
the adoption of FP, IPM, or weekly applications of
insecticide to various Brassica vegetable crops. Spe-
ciÞcally, we distribute the total area of Brassica crop
production to each grid location, j for example, rela-
tive to the GI value, for grid locations or cells with
GI 15, to get A
j
.
Insecticide application costs can vary a great deal,
and we use US$35/ha for farmer practice and US$40
for IPM for all crops. Pesticides vary enormously in
costs depending on the product being used and ap-
plication costs (e.g., fuel, labor costs). The higher cost
for IPM reßects the additional labor costs of sampling
and probably use of more expensive products. If all of
these costs are included, then our estimates are not
unreasonable for costs encountered in China (Liu et
al. 2004), Canada (insecticide application to canola
costs US$35/ha; L. Dosdall, personal communication)
and the United States (insecticide and application
costs estimated to be US$74/ha in U.S. vegetable
crops; A. Shelton, personal communication).
Thus, the cost of management for each country will
be given by the product of: A
j
SPH
j
CPS
j
, summed
over each grid location j, where A
j
is the area of
production in ha for each Brassica crop type, SPH
j
is
the number of insecticide applications per hectare
either for the worst-case scenario (weekly), best FP or
threshold-based IPM, and CPS
j
is cost/spray for each
crop. For simplicity of presentation we present data
summed for each continent (Table 2); national area of
production data and estimated control costs under the
different application regimes can be found in Appen-
dix 1.
The overall cost of diamondback moth will equal the
cost of management plus the lost production even with
management, i.e., yield loss with management. This is
a measure of how ineffective management is due to
poor spray timing, poor application (coverage), in-
secticide resistance, and so forth. Estimates regarding
the yield losses caused by diamondback moth cover an
enormous range and losses in many tropical develop-
ing countries are likely to be much higher than in
temperate regions of industrialized countries. We use
production values for the crops published by the Food
and Agriculture Organization (FAO) (FAOSTAT
2012) and use these gross data and an assumed level
of 5% decrease in crop value to estimate yield losses
due to diamondback moth.
Test of CLIMEX Model
Predicted and Actual Geographic Distributions.
The predicted worldwide distribution, mapped as EI
values (Fig. 1a) and GI values (Fig. 1b) based on the
set of CLIMEX parameters described in Zalucki and
Furlong (2011) for diamondback moth agrees well
Table 2. Estimated annual costs of diamond back moth control for different crops on each continent when treated with insecticide
weekly or managed by rational FP or an IPM strategy
Brassica crop Continent Cost of insecticide application strategy (US$)
Weekly Single FP Rational FP IPM
Cabbage Africa $46,097,772 $19,202,651 $11,141,005
Australia and PaciÞc $1,169,364 $457,579 $267,545
Asia $695,435,398 $276,309,868 $161,195,709
Europe $216,137,670 $91,065,120 $52,762,140
North and Central America $42,129,738 $19,060,394 $10,952,758
South America $5,644,128 $2,231,623 $1,303,107
Global total $1,006,614,070 $408,327,234 $237,622,266
Caulißower and broccoli Africa $5,433,960 $1,773,879 $1,063,439
Australia and PaciÞc $3,447,234 $1,292,478 $759,913
Asia $291,613,130 $111,784,037 $65,524,683
Europe $58,007,430 $23,238,373 $13,547,207
North and Central America $19,788,426 $8,361,502 $4,842,898
South America $23,656,962 $12,056,249 $6,840,740
Global total $401,947,142 $158,506,518 $92,578,880
Canola Africa $2,857,157 $13,475,282 $7,874,566
Australia and PaciÞc $45,818,497 $199,996,489 $118,066,148
Asia $475,528,620 $2,184,449,699 $1,280,853,119
Europe $211,162,386 $1,108,960,398 $639,659,862
North and Central America $195,127,090 $974,026,206 $565,206,806
South America $4,127,208 $23,057,347 $13,207,633
Global total $934,620,957 $4,503,965,422 $2,624,868,134
1118 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 4
with the knownworldwide distribution (Common-
wealth Institute of Entomology 1967, CAB 2012). Re-
gions with values of EI below 15 are probably mar-
ginal for long-term persistence of a species; essentially
such conditions are associated with the edge of the
species core range (Fig. 1a). The potential increase in
the species range when GI values are plotted (Fig. 1b)
should be noted. This area represents the maximal
range that diamondback moth can exploit if it migrates
out of its core (Fig. 1a) and colonizes these locations
at a time when prevailing seasonal conditions result in
a positive GI. Such migrations are highly variable from
year to year (Zalucki and Furlong 2005, 2008, 2011).
The Þne scaleÐpredicted distribution of diamond-
back moth in Japan (Fig. 1a and b) agrees well with
observations of the speciesÕ actual distribution in this
region. Diamondback moth does not persist in north-
ern Japan, but it does so in southern regions (Honda
1992) and makes annual reinvasions of northern Japan.
Again the geographic distribution in Japan is a pre-
diction based on our model parameter values, and it
was not used to generate the model. Similarly, the
species does not usually persist on the Korean penin-
sula but reinvades each year, most likely from China,
and populations build up when GI values are suitable
in the springÐsummer (Furlong et al. 2008). The
northern range limit of seasonal breeding in China
(Fig. 1a) seems to agree well with observations there
(Li et al. 2012).
Predicted and Actual Seasonal Phonologies.
CLIMEX can be used to predict average season phe-
nology at a site in terms of weekly growth indices. We
have done so for 11 locations around the world that
vary widely in their suitability for diamondback moth,
Fig. 1. Predicted geographic distribution of diamondback moth worldwide. (a) Values where EI is positive denote the
core of the species range and year round occupation. (b) Regions where GI is positive indicate the potential migratory seasonal
range. The actualdistribution CAB maps can be found in the CABI Crop Protection Compendium (CABI 2012).
August 2012 ZALUCKI ET AL.: ECONOMIC COST OF P. xylostella 1119
by using climatic data for an average year at each
location (locations are marked on Fig. 1). Again, the
predicted values agree well with observed values
across a range of sites (Fig. 2aÐk). This is not unex-
pected for the Cameron Highlands, Malaysia (Fig. 2a)
because these data were used to parameterize the
initial model (Zalucki and Furlong 2008). However,
many other sites across a wide range of geographic
locations(northern Luzon, Philippines [Fig. 2b],
China [Fig. 2cÐ e; in Fig. 2e, high populations recorded
in weeks 21Ð27 probably are the result of migration
event; population changes after week 28 follow a very
similar pattern to the growth indices predicted by the
model], Japan [Fig. 2f], India [Fig. 2g], Kenya [Fig.
2h], the United Kingdom [Fig. 2i], and Mexico [Fig.
2j]) show good visual agreement between observed
and predicted phenology, but there is a poor Þt for a
site in South Africa (Fig. 2k). The sites that were used
for these comparisons were sites for which diamond-
back moth population monitoring data could be iden-
tiÞed in one form or another (sampling of larvae on
plants, pheromone traps, and light traps) to estimate
the species seasonal phenology/abundance at the site.
Importantly, these abundance data reßect not only
vital population rates of birth, death, and movement as
inßuenced by climate and host plant (crop and non-
crop weedy Brassica species) but also widespread in-
tensive management, namely, insecticide application.
In general the modelÕs GI is a leading indicator of
population buildup, as one would expect as it is a
measure of potential growth rate. Outside areas where
EI is positive (Fig. 1a), the seasonal dynamics will have
a strong migration component. That our simple model
by and large captures both spatial (Fig. 1a and b) and
seasonal temporal dynamics (Fig. 2) argues that there
is nothing particularly special about the speciesÕ biol-
ogy and ecology at speciÞc locations throughout its
range. The predictions are based on one set of param-
eters and climate data for each location. We therefore
use our CLIMEX model to predictdiamondback
moth abundance throughout its range and undertake
an analysis of possible management costs.
Estimated Cost of Diamondback Moth
Management and Losses
A few things stand out in terms of how much dia-
mondback moth control costs the world economy
(Table 2). For vegetable crops, if management is based
on weekly spray regimes, then diamondback moth
costs US$1.4 billion. If diamondback moth is only
treated with insecticide as required, when average GI
is suitable for diamondback moth population growth,
then the predicted control costs are US$566 million;
this drops to US$340 million if IPM strategies are
assumed to be universally adopted for vegetable crops
(Table 2). The latter assumes diamondback moth
abundance is entirely determined by climate. We have
not calculated a control cost based on weekly spraying
of canola because this is unlikely ever to be the case.
Spraying this crop a single time during the crop cycle
adds US$935 million to management costs if a single
spray farmer practice intervention is assumed (Table
2). If diamondback moth in canola is managed using
IPM or farmer practice regimes based on climate that
are equivalent to those in vegetable crops, then con-
trol costs are estimated to be in the region of US$2.6
billion and US$4.5 billion, respectively (Table 2).
However, such assessments must be interpreted with
caution, as in canola economic thresholds are usually
much higher than for Brassica vegetable crops.
Based on these estimates our approach predicts a
lower bound for the management costs of diamond-
back moth in all crops of US$1.27 billion (US$340
million for all vegetables, assuming the adoption of
IPM, and US$935 million for canola, assuming a single
insecticide application) and an upper bound of
US$2.3 billion (US$1.4 billion for all vegetables
based on weekly insecticide application and US$935
million for canola, assuming a single insecticide ap-
plication across the global distribution of the crop).
The real value will lie somewhere between these
bounds. In 2009, the annual value of Brassica vegetable
and canola crops was estimated to be US$51 billion
(FAO STAT 2012), meaning that just 5% crop loss due
to the damage caused by diamondback moth would
add another US$2.7 billion to the total economic costs,
which can be attributed to this destructive pest. So, the
piece of string could be US$5.0 billion long!
Vegetable production is extremely high in Asia and
this continent consequently dominates loss estimates
(Table 2; Fig. 3). Examination of Fig. 3 allows calcu-
lation of estimated control costs for a given continent
based on the assumption of a continuum (0Ð100%) of
weekly insecticide applications; when crops are not
treated weekly it is assumed that there is equal adop-
tion of farmer practice and IPM-based management
strategies. Using these data it is possible to determine
a range of estimates for the worldwide costs of dia-
mondback moth management by assuming different
adoption rates of different pest management strategies
in different continents. Such an approach will more
likely lead to a more precise estimate of actual man-
agement costs than we attempt above. Similarly the
national data that were generated and used to deter-
mine the continental estimates (Appendix 1) are a
useful resource that enables diamondback moth con-
trol costs in each country to be estimated based on
assumptions regarding the local adoption rates of dif-
ferent pest management strategies.
Discussion
If we assume that the cost of diamondback moth of
US$1billion was correct in 1993, then, at a minimum,
one should allow for inßation. The net present value
of this sum is US$2.65 billion assuming 5% inßation per
annum and US$1.81 billion if an inßation rate of 3% is
applied. Furthermore, there have been dramatic in-
creases in both Brassica vegetable (39% increase) and
canola (59% increase) production areas since 1993,
and there is now an additional crop area of 12 million
ha/annum available to the pest that requires protec-
tion (FAOSTAT 2012). This represents an overall in-
1120 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 4
Fig. 2. Seasonal phenology of diamondback moth for locations throughout its range (see Fig. 1) based on various methods
to observe the species abundance (solid line, details below) plotted with the CLIMEX GI value (dashed line) based on average
climatic conditions at the location provided by CLIMEX. The x-axis varies depending on how the base data were collected
(e.g., weekly, monthly). (a) Cameron highlands, Malaysia, (428N, 10123E; 1,470 m), larvae per 10 plants (Ooi 1992).
(b) La Trinidad, northern Luzon (856N, 12531E), light and pheromone trap (Poelking 1992). (c) Hangzhou, China
(3014N, 12026E) (Zalucki and Furlong 2011). (d) Huadu, China (2323N, 11428E; 6.6 m) (Li et al. 2012). (e) Beijing
(4028N, 11558E), China, larvae per 100 plants (Shi et al. 2008). (f) Hiratsuka, Kanagawa (3519N, 13921E), Japan,
pheromone trap (Kuwahara et al. 1995). (g) Aligarh district (2753N, 785E), India, larvae per plant, (Ahmad and Ansari
2010). (h) Naivasha, Nakuru district, the Rift Valley, altitude, 1,500 m (0045S, 03626E), Kenya, larvae per 20 plants
(Rossbach et al. 2008). (i) Holbeach, Lincolnshire (5248N, 01E), United Kingdom, larvae per 20 plants (Collier and
Finch 2004). (j) Salamanca (2034N, 10112W), Mexico, pheromone trap (McCully and Araiza Salas 1992). (k) Brits (25
25S, 2776E, altitude, 1,100 m), South Africa, pheromone trap (KÞr 1997, 2004; Nofemela and KÞr 2008).
August 2012 ZALUCKI ET AL.: ECONOMIC COST OF P. xylostella 1121
crease of 57% to the global Brassica cropping area
since 1993, and whatever the merits of the previous
US$1 billion estimate it is clearly outdated, even with-
out consideration of the increased intensiÞcation of
practices that have accompanied this change.
Our analysis suggests that the management of dia-
mondback moth in Brassica vegetable crops alone
costs US$1.4 billion when based on the conservative
assumption of a management regime of one insecti-
cide application per week (Table 2). When the cost of
managing diamondback moth in canola is included the
total cost estimate for management increases to
US$2.3 billion. These estimates are at the extreme
range and represent the worst-case scenario of a single
spray to every canola crop and weekly spraying for
vegetables (Table 2). The latter is not uncommon for
diamondback moth on vegetable crops in many parts
of the speciesÕ range, particularly in the tropics where
insecticide application rates can be even higher (Ma-
zlan and Mumford 2005, Williamson 2005, Atumuri-
rava and Furlong 2011). As has been suggested by
many studies, diamondback moth is an induced pest
that can, to a large extent, be controlled by natural
enemies (KÞr 2004, Furlong et al. 2008, Li et al. 2012).
Our work in China (Liu et al. 2005), Democratic
PeopleÕs Republic of Korea (Furlong et al. 2008), and
Australia (Furlong et al. 2004a,b) indicates that it is
possible to greatly reduce management costs by mov-
ing away from weekly insecticide application and the
adoption of threshold-based IPM (Zalucki et al. 2009).
If management was based on diamondback moth pop-
ulations requiring control only when climatic condi-
tions were suitable, then even rational farmer practice
would reduce costs to US$560 million in vegetables
and adoption of IPM would reduce these costs by a
further 42% (Table 2). As has been found in Australia
(Furlong et al. 2004a,b); China (Li et al. 2012); the
Cameron Highlands, Malaysia (Ooi 1992); New Zea-
land (Walker et al. 2004); and South Africa (KÞr 1997,
2004), if natural enemies are not disrupted by broad-
spectrum insecticides and allowed to exert population
suppressive forces on the pest, then costs associated
with the management diamondback moth would be
even less.
The cost estimate is based on a CLIMEX prediction
of population size based on GI and decision making as
in our trials in China (Table 2). So, how reasonable is
our model and approach? CLIMEX has been used
extensively in biological control programs and pest
risk analysis to predict potential distributions of var-
ious species (for brief reviews, see Zalucki and Fur-
long 2005, van Klinken et al. 2009, Lawson et al. 2010).
However, this method has not yet been used widely to
model population changes of a species (but see Za-
lucki and Furlong 2005; Zalucki and van Klinken 2006;
Zalucki and Furlong 2008, 2011; Li et al. 2012). The
CLIMEX parameter set integrates data on species dis-
tribution into a single model. This approach may be
used to generate a climate driven null model for the
abundance of a species at a site over time. Such models
that enable one to infer likely species abundance
based on climate are critical to testing the effective-
ness of management strategies such as areawide man-
agement and the planting of transgenic crops (Carri-
e`re et al. 2003, Zalucki and Furlong 2005), as well as
predicting temporal dynamics and outbreaks of pests
(e.g., Maelzer et al. 1996). Historical climate data can
be used to predict both the expected changes in range
and variation in the seasonal and annual temporal
dynamics of the pest and therefore of likely pest status.
In our estimates of management costs, we use our
CLIMEX model to generate diamondback moth spa-
tial abundance and the scale of the problem that it
represents. The validity of the model rests on how well
the predictions match reality. Geographically, the pre-
dictions accord well with notions about the distribu-
tion of diamondback moth, but surprisingly, there is no
real data to test against per se. Predictions of seasonal
Fig. 3. Estimated costs of diamondback moth control in
vegetable Brassica crops for each continent (cabbages [and
leafy Chinese greens], caulißower and broccoli) along a
continuum of insecticide interventions: 1, weekly application
of insecticide by 100% of farmers in a given region; 0, weekly
application of insecticide by 0% of farmers in a given region.
When crops are not treated with insecticide weekly, equal
adoption of FP- and IPM-based insecticide applications are
assumed.
1122 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 4
phenology (Fig. 2) provide good approximations to
Þeld data for almost all locations tested. Zalucki and
Furlong (2008, 2011) and Li et al. (2012) took this one
step further and showed that the model was even
useful for long-term population data sets.
Our other assumption is that Brassica crops are the
same as diamondback moth, and we have distributed
Brassica production areas accordingly. In practice, ar-
eas of agriculture are more concentrated depending
on soil, topography, water availability, and other fac-
tors that affect land use. The distribution of host plants
also will impact on populations of insects (e.g., Zalucki
and Lammers 2010) and of course their pest status
(Schellhorn et al. 2008). These matters are beyond the
scope of this paper, but they are unlikely to change key
Þndings substantially. We might expect areas of high
production to lead to higher levels of pest abun-
danceÑthe resource concentration hypothesis on a
landscape scale.
Our country estimates are close to local experts
opinions. In the United States, Anthony Shelton (per-
sonal communication) estimates that management
cost associated with Brassica vegetables are of the
order of US$220 million; our equivalent estimate is
US$46 million. The difference can be explained due
to different estimates of the area of production; the
FAO estimates that the area of production is 71,000
ha (FAOSTAT 2012), whereas Shelton used USDA
estimates of 107,000 ha; and differences in assumed
management costs per ha; we use US$35Ð40/ha but
Shelton uses more than double this Þgure (see above).
Allowing for these differences, our equivalent esti-
mate would be US$150 million, a value that is sur-
prisingly close. Sandur (2004) has estimated that di-
amondback moth management in vegetable crops in
India costs US$168 million/annum, we estimate
costs to be US$45ÐUS$217 million, depending on the
relative degree of adoption of IPM and weekly insec-
ticide application (Appendix 1).
Our estimates are probably conservative for two
major reasons. First, our assumptions about manage-
ment costs and the frequency of insecticide use is
likely to be an underestimate of common practices in
many parts of the world where insecticides are fre-
quently applied to Brassica vegetable crops more than
two times per week (Mazlan and Mumford 2005, Wil-
liamson 2005, Atumurirava and Furlong 2011). If this
were universally the case, then the upper cost for
vegetables would be double our current estimate. Sec-
ond, the ofÞcial FAO statistics that we have used as the
basis of our cost calculations (FAOSTAT 2012) un-
derestimate the area of Brassica crops grown. This is
well illustrated by the example the United States dis-
cussed above, and Appendix 1 shows that the produc-
tion area data that we used (FAOSTAT 2012) indicate
that many countries, even some in which diamond-
back moth is a renowned and signiÞcant pest, e.g.,
Taiwan, Myanmar, Laos, and Papua New Guinea, pro-
duce no Brassica crops at all! Indeed, the database
returns zero production data for 35 of the 168 coun-
tries for which data could be retrieved. Although the
effect of such discrepancies is in itself signiÞcant, an
even greater source of error is likely to derive from the
fact that in many developing countries signiÞcant
quantities of Brassica crops are grown in the subsis-
tence sector. Although these crops are frequently in-
tensively managed with insecticides, they often con-
tribute only to local rural economies, and as such
production data do not enter ofÞcial statistics.
In conclusion, diamondback moth is an enormous
economic problem, and certainly it now costs much
US$1 billion/annum to manage. Management costs
and lost production probably make diamondback
moth a US$4ÐUS$5 billion problem. Current manage-
ment relies heavily on insecticide applications, some-
times under the guise of threshold based IPM. As has
happened repeatedly, insecticide resistance develops
rapidly (e.g., Li et al. 2012) and reliance on insecti-
cides is not sustainable. Our experience and analysis
suggest that worldwide adoption of even basic IPM
would dramatically reduce costs and allow natural
enemies to contribute to pest population suppression.
To achieve more efÞcient and long-term control,
adoption of improved management must be facili-
tated; this is de´ja`vu all over again(Shelton 2004).
Acknowledgments
We thank the many colleagues who have worked to im-
prove management of diamondback moth and provided es-
timates of how much it costs to manage this pest. We thank
Australian Centre for International Agricultural Research for
funding of projects on diamondback moth in China (CS2/
1998/089, Democratic PeopleÕs Republic of Korea (HORT/
2004/062), and the South PaciÞc (PC/2004/063 and PC/
2010/090).
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Received 12 March 2012; accepted 18 May 2012.
August 2012 ZALUCKI ET AL.: ECONOMIC COST OF P. xylostella 1125
Appendix 1. Mean production data and associated cost estimates for diamondback moth management under different management practices and scenarios for all countries for which data were available
(FAOSTAT 2012)
Continent Country
Mean production
area (Ha) 2000Ð2009
Estimated costs (US$) based
on farmer practice (FP)
Estimated costs (US$) based
on IPM adoption
Estimated costs (US$)
based on weekly
application of
insecticide (FP)
Estimated costs based
of single application
of insecticide to canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli FP IPM
Africa Algeria 2,580 4,175 15,199 $297,585 $481,594 $1,753,243 $183,413 $296,825 $1,080,592 $1,083,516 $1,753,500 $531,969 $607,964
Africa Angola 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Benin 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Botswana 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Burkina Faso 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Burundi 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Cameroon 2,874 0 0 $529,622 $0 $0 $305,397 $0 $0 $1,206,954 $0 $0 $0
Africa Central African
Republic
00 0$0$0$0 $0 $0$0$0$0$0$0
Africa Chad 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Congo 91 0 0 $19,432 $0 $0 $11,030 $0 $0 $38,262 $0 $0 $0
Africa Coˆte dÕIvoire 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Democratic Republic
of the Congo
1,516 0 0 $309,090 $0 $0 $176,258 $0 $0 $636,678 $0 $0 $0
Africa Egypt 20,199 4,798 0 $2,745,866 $652,294 $0 $1,648,247 $391,549 $0 $8,483,622 $2,015,328 $0 $0
Africa Equatorial Guinea 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Eritrea 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Ethiopia 21,308 0 24,150 $3,871,402 $0 $4,387,795 $2,236,076 $0 $2,534,338 $8,949,360 $0 $845,257 $966,008
Africa Gabon 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Ghana 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Guinea 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Kenya 32,824 92 0 $6,685,930 $18,679 $0 $3,813,042 $10,653 $0 $13,785,870 $38,514 $0 $0
Africa Lesotho 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Liberia 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Madagascar 788 53 0 $177,216 $11,982 $0 $100,067 $6,766 $0 $331,086 $22,386 $0 $0
Africa Malawi 3,418 0 0 $631,586 $0 $0 $364,078 $0 $0 $1,435,350 $0 $0 $0
Africa Mali 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Mauritania 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Morocco 1,462 2,066 940 $225,901 $319,346 $145,284 $133,150 $188,228 $85,633 $613,872 $867,804 $32,900 $37,600
Africa Mozambique 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Namibia 145 0 0 $17,736 $0 $0 $10,824 $0 $0 $60,900 $0 $0 $0
Africa Niger 9,192 0 0 $920,872 $0 $0 $582,367 $0 $0 $3,860,556 $0 $0 $0
Africa Nigeria 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Rwanda 4,259 0 0 $1,221,522 $0 $0 $675,370 $0 $0 $1,788,864 $0 $0 $0
Africa Senegal 1,642 0 0 $162,644 $0 $0 $103,085 $0 $0 $689,682 $0 $0 $0
Africa Sierra Leone 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Somalia 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa South Africa 2,785 1,178 36,964 $496,851 $210,148 $6,594,660 $287,590 $121,639 $3,817,164 $1,169,658 $494,718 $1,293,731 $1,478,550
Africa Sudan 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Swaziland 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Togo 44 0 0 $6,494 $0 $0 $3,856 $0 $0 $18,606 $0 $0 $0
Africa Tunisia 1,556 544 4,380 $211,167 $73,813 $594,301 $126,792 $44,320 $356,838 $653,646 $228,480 $153,300 $175,200
Africa Uganda 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa United Republic of
Tanzania
3,047 0 0 $666,535 $0 $0 $377,377 $0 $0 $1,279,866 $0 $0 $0
1126 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 4
Appendix 1. Continued
Continent Country
Mean production
area (Ha) 2000Ð2009
Estimated costs (US$) based
on farmer practice (FP)
Estimated costs (US$) based
on IPM adoption
Estimated costs (US$)
based on weekly
application of
insecticide (FP)
Estimated costs based
of single application
of insecticide to canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli FP IPM
Africa Western Sahara 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Zambia 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Africa Zimbabwe 27 32 0 $5,202 $6,024 $0 $2,987 $3,459 $0 $11,424 $13,230 $0 $0
Asia Afghanistan 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Asia Azerbaijan 6,286 0 0 $512,233 $0 $0 $338,307 $0 $0 $2,640,288 $0 $0 $0
Asia Bangladesh 13,606 13,049 266,274 $2,525,335 $2,421,901 $49,420,247 $1,455,018 $1,395,422 $28,474,369 $5,714,688 $5,480,622 $9,319,597 $10,650,968
Asia Bhutan 698 158 0 $105,119 $23,811 $0 $62,180 $14,084 $0 $293,230 $66,420 $0 $0
Asia Cambodia 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Asia China 1,007,443 343,496 6,900,183 $184,176,369 $62,796,470 $1,261,461,219 $106,301,520 $36,244,390 $728,080,617 $423,126,186 $144,268,404 $241,506,405 $276,007,320
Asia India 261,720 281,790 5,906,150 $36,148,477 $38,920,523 $815,750,900 $21,647,301 $23,307,324 $488,507,589 $109,922,400 $118,351,800 $206,715,250 $236,246,000
Asia Indonesia 68,055 7,250 0 $8,339,115 $888,317 $0 $5,087,838 $541,978 $0 $28,583,100 $3,044,790 $0 $0
Asia Iran 11,279 1,144 105,800 $1,278,847 $129,682 $11,996,457 $790,554 $80,166 $7,415,936 $4,736,970 $480,354 $3,703,000 $4,232,000
Asia Iraq 1,275 2,370 0 $153,611 $285,536 $0 $93,983 $174,697 $0 $535,500 $995,400 $0 $0
Asia Israel 1,974 1,474 0 $397,616 $296,863 $0 $227,033 $169,504 $0 $829,080 $618,996 $0 $0
Asia Japan 46,630 12,041 728 $7,546,034 $1,948,570 $117,875 $4,420,902 $1,141,584 $69,058 $19,584,600 $5,057,220 $25,494 $29,136
Asia Jordon 710 2,390 0 $130,474 $439,109 $0 $75,261 $253,290 $0 $298,200 $1,003,590 $0 $0
Asia Kazakhstan 14,865 23 72,826 $1,441,387 $2,230 $7,061,737 $917,387 $1,419 $4,494,521 $6,243,132 $9,660 $2,548,896 $2,913,024
Asia Korea North 34,474 0 0 $6,124,644 $0 $0 $3,546,879 $0 $0 $14,479,080 $0 $0 $0
Asia Korea South 48,404 0 1,045 $8,433,009 $0 $182,008 $4,895,164 $0 $105,651 $20,329,680 $0 $36,575 $41,800
Asia Kuwait 209 232 0 $0 $0 $0 $0 $0 $0 $87,906 $97,524 $0 $0
Asia Kyrgyzstan 5,017 117 486 $423,294 $9,872 $41,041 $277,385 $6,469 $26,894 $2,107,014 $49,140 $17,024 $19,456
Asia Laos 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Asia Lebanon 1,563 1,015 0 $278,047 $180,502 $0 $160,995 $104,514 $0 $656,418 $426,132 $0 $0
Asia Malaysia 1,508 0 0 $216,141 $0 $0 $128,738 $0 $0 $633,360 $0 $0 $0
Asia Mongolia 1,652 0 0 $189,773 $0 $0 $117,051 $0 $0 $693,924 $0 $0 $0
Asia Myanmar 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Asia Nepal 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Asia Oman 296 132 0 $11,633 $5,175 $0 $9,559 $4,252 $0 $124,320 $55,300 $0 $0
Asia Pakistan 4,431 11,389 322,738 $512,343 $1,316,988 $37,321,360 $315,641 $811,363 $22,992,742 $1,860,810 $4,783,254 $11,295,820 $12,909,508
Asia Philippines 7,899 1,065 0 $1,440,777 $194,286 $0 $831,797 $112,166 $0 $3,317,580 $447,370 $0 $0
Asia Qatar 97 90 0 $0 $0 $0 $0 $0 $0 $40,740 $37,926 $0 $0
Asia Saudi Arabia 2,798 0 0 $120,073 $0 $0 $95,516 $0 $0 $1,175,118 $0 $0 $0
Asia Sri Lanka 4,003 0 0 $742,953 $0 $0 $428,066 $0 $0 $1,681,260 $0 $0 $0
Asia Syrian Arab Republic 2,010 1,654 0 $242,378 $199,399 $0 $148,269 $121,978 $0 $844,158 $694,470 $0 $0
Asia Taiwan 0 0 0 $0 $0 $0 $0 $0 $0
Asia Tajikistan 1,697 0 432 $149,624 $0 $38,050 $97,113 $0 $24,696 $712,656 $0 $15,103 $17,260
Asia Thailand 27,331 5,251 0 $3,549,605 $682,011 $0 $2,145,627 $412,254 $0 $11,478,810 $2,205,504 $0 $0
Asia Turkey 29,434 5,979 8,213 $3,314,594 $673,335 $924,830 $2,051,475 $416,742 $572,397 $12,362,280 $2,511,306 $287,441 $328,504
Asia Turkmenistan 3,030 0 0 $0 $0 $0 $0 $0 $0 $1,272,600 $0 $0 $0
Asia United Arab Emirates 782 365 0 $0 $0 $0 $0 $0 $0 $328,566 $153,132 $0 $0
Asia Uzbekistan 8,983 0 1,658 $726,052 $0 $133,976 $480,412 $0 $88,649 $3,772,860 $0 $58,016 $66,304
Asia Viet Nam 35,169 1,845 0 $7,043,179 $369,457 $0 $4,024,021 $211,084 $0 $14,770,770 $774,816 $0 $0
Asia Yemen 472 0 0 $37,130 $0 $0 $24,719 $0 $0 $198,114 $0 $0 $0
Australia & PaciÞc Australia 1,929 7,105 1,307,171 $294,555 $1,085,090 $199,633,716 $173,896 $640,603 $117,857,444 $810,054 $2,984,100 $45,750,985 $52,286,840
Australia & PaciÞc Fiji 70 0 0 $15,255 $0 $0 $8,638 $0 $0 $29,316 $0 $0 $0
Australia & PaciÞc New Caledonia 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Australia & PaciÞc New Zealand 786 1,103 1,929 $147,769 $207,388 $362,774 $85,011 $119,310 $208,704 $329,994 $463,134 $67,512 $77,156
Australia & PaciÞc Papua New Guinea 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Australia & PaciÞc Solomon Islands 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Australia & PaciÞc Vanuatu 0 0 0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
August 2012 ZALUCKI ET AL.: ECONOMIC COST OF P. xylostella 1127
Appendix 1. Continued
Continent Country
Mean production
area (Ha) 2000Ð2009
Estimated costs (US$) based
on farmer practice (FP)
Estimated costs (US$) based
on IPM adoption
Estimated costs (US$)
based on weekly
application of
insecticide (FP)
Estimated costs based
of single application
of insecticide to canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli FP IPM
Europe Albania 1,291 161 0 $203,491 $25,419 $0 $104,676 $13,075 $0 $542,346 $67,746 $0 $0
Europe Armenia 3,328 247 0 $313,272 $23,235 $0 $200,571 $14,876 $0 $1,397,550 $103,656 $0 $0
Europe Austria 1,826 296 48,189 $351,379 $57,033 $9,271,598 $201,634 $32,727 $5,320,382 $767,046 $124,500 $1,686,626 $1,927,572
Europe Belarus 21,225 0 154,093 $4,447,894 $0 $32,291,256 $2,529,191 $0 $18,361,667 $8,914,584 $0 $5,393,248 $6,163,712
Europe Belgium 3,711 4,035 6,956 $759,397 $825,736 $1,423,399 $432,883 $470,699 $811,388 $1,558,704 $1,694,868 $243,467 $278,248
Europe Bosnia and
Herzegovina
6,569 0 811 $1,359,386 $0 $167,766 $773,988 $0 $95,520 $2,758,980 $0 $28,375 $32,428
Europe Bulgaria 4,401 334 33,926 $581,787 $44,211 $4,485,270 $350,705 $26,651 $2,703,748 $1,848,210 $140,448 $1,187,393 $1,357,020
Europe Croatia 5,771 224 15,880 $1,208,497 $46,949 $3,325,303 $687,234 $26,699 $1,890,994 $2,423,820 $94,164 $555,783 $635,180
Europe Cyprus 124 77 0 $22,078 $13,645 $0 $12,783 $7,901 $0 $52,122 $32,214 $0 $0
Europe Czech Republic 3,150 972 309,816 $641,590 $198,063 $63,111,117 $365,902 $112,956 $35,992,581 $1,322,832 $408,366 $10,843,557 $12,392,636
Europe Denmark 828 608 124,219 $173,546 $127,534 $26,039,115 $98,680 $72,517 $14,806,062 $347,718 $255,528 $4,347,676 $4,968,772
Europe Estonia 819 62 52,878 $167,102 $12,583 $10,783,603 $95,288 $7,175 $6,149,221 $344,148 $25,914 $1,850,744 $2,115,136
Europe Finland 1,015 517 75,410 $155,276 $79,083 $11,535,150 $91,650 $46,678 $6,808,515 $426,342 $217,140 $2,639,350 $3,016,400
Europe France 9,793 26,864 1,267,009 $1,706,918 $4,682,328 $220,834,869 $990,773 $2,717,838 $128,182,662 $4,113,144 $11,282,964 $44,345,315 $50,680,360
Europe Georgia 10,660 0 0 $1,982,314 $0 $0 $1,141,894 $0 $0 $4,477,200 $0 $0 $0
Europe Germany 15,065 6,560 1,322,457 $3,016,672 $1,313,528 $264,815,506 $1,723,556 $750,475 $151,300,604 $6,327,258 $2,755,032 $46,285,995 $52,898,280
Europe Greece 8,417 4,381 3,750 $1,117,811 $581,834 $498,021 $673,359 $350,491 $300,003 $3,535,098 $1,840,062 $131,250 $150,000
Europe Hungary 5,067 1,266 152,780 $752,301 $187,949 $22,685,084 $445,857 $111,389 $13,444,481 $2,127,972 $531,636 $5,347,286 $6,111,184
Europe Ireland 899 909 4,200 $120,351 $121,690 $562,449 $72,406 $73,212 $338,384 $377,454 $381,654 $147,000 $168,000
Europe Italy 20,232 20,817 13,533 $3,632,788 $3,737,831 $2,430,005 $2,101,156 $2,161,911 $1,405,482 $8,497,272 $8,742,972 $473,659 $541,324
Europe Latvia 3,108 227 54,360 $679,212 $49,692 $11,878,886 $384,590 $28,137 $6,726,178 $1,305,444 $95,508 $1,902,600 $2,174,400
Europe Lithuania 5,238 353 112,150 $1,134,463 $76,370 $24,290,745 $642,933 $43,281 $13,766,274 $2,199,876 $148,092 $3,925,250 $4,486,000
Europe Netherlands 7,189 3,850 1,836 $1,428,425 $765,011 $364,861 $816,799 $437,447 $208,634 $3,019,254 $1,617,000 $64,267 $73,448
Europe Norway 1,029 947 7,053 $156,170 $143,640 $1,070,022 $80,746 $74,267 $553,243 $432,180 $397,740 $246,855 $282,120
Europe Poland 37,501 13,493 583,532 $7,490,246 $2,695,071 $116,551,114 $4,280,674 $1,540,233 $66,608,948 $15,750,462 $5,667,186 $20,423,606 $23,341,264
Europe Portugal 9,353 2,071 0 $1,739,614 $385,110 $0 $1,002,069 $221,835 $0 $3,928,386 $869,652 $0 $0
Europe Republic of Moldova 4,458 118 16,302 $620,152 $16,414 $2,267,548 $370,987 $9,819 $1,356,489 $1,872,486 $49,560 $570,553 $652,060
Europe Romania 44,900 1,536 153,127 $7,869,272 $269,235 $26,837,204 $4,564,644 $156,172 $15,567,168 $18,858,168 $645,204 $5,359,459 $6,125,096
Europe Russian Federation 147,208 1,267 322,734 $25,638,954 $220,723 $56,210,003 $14,883,345 $128,129 $32,629,759 $61,827,360 $532,266 $11,295,690 $12,909,360
Europe Serbia and
Montenegro
23,636 0 3,461 $4,323,296 $0 $633,040 $2,495,129 $0 $365,350 $9,926,910 $0 $121,129 $138,433
Europe Slovakia 6,457 1,090 117,629 $1,242,109 $209,660 $22,627,814 $712,781 $120,313 $12,984,916 $2,711,940 $457,758 $4,117,008 $4,705,152
Europe Slovenia 836 89 2,690 $168,805 $18,040 $543,345 $96,355 $10,297 $310,145 $350,952 $37,506 $94,136 $107,584
Europe Spain 8,474 24,660 12,555 $1,086,725 $3,162,352 $1,610,024 $658,198 $1,915,347 $975,146 $3,559,122 $10,356,990 $439,415 $502,188
Europe Sweden 414 418 73,456 $69,549 $70,136 $12,328,141 $40,558 $40,900 $7,189,179 $174,048 $175,518 $2,570,960 $2,938,240
Europe Switzerland 1,081 658 17,308 $198,458 $120,816 $3,178,325 $114,485 $69,695 $1,833,488 $453,894 $276,318 $605,763 $692,300
Europe The former Yugoslav
Republic of
Macedonia
3,523 24 698 $423,947 $2,840 $84,029 $259,426 $1,738 $51,420 $1,479,492 $9,912 $24,437 $27,928
Europe Ukraine 74,930 1,770 427,170 $12,366,548 $292,123 $70,500,710 $7,226,820 $170,712 $41,199,531 $31,470,600 $743,400 $14,950,950 $17,086,800
Europe United Kingdom 11,089 17,212 541,245 $1,715,323 $2,662,488 $83,725,078 $1,010,923 $1,569,134 $49,343,266 $4,657,296 $7,228,956 $18,943,589 $21,649,816
North & Central
America
Belize 60 0 0 $11,500 $0 $0 $6,601 $0 $0 $25,158 $0 $0 $0
North & Central
America
Canada 8,647 2,312 5,116,870 $1,494,696 $399,699 $884,528,363 $868,459 $232,236 $513,935,089 $3,631,572 $971,124 $179,090,450 $204,674,800
1128 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 4
Appendix 1. Continued
Continent Country
Mean production
area (Ha) 2000Ð2009
Estimated costs (US$) based
on farmer practice (FP)
Estimated costs (US$) based
on IPM adoption
Estimated costs (US$)
based on weekly
application of
insecticide (FP)
Estimated costs based
of single application
of insecticide to canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli Canola
Cabbages
& other
brassicas
Caulißower
and broccoli FP IPM
North & Central
America
Costa Rica 2,997 0 0 $425,580 $0 $0 $253,821 $0 $0 $1,258,614 $0 $0 $0
North & Central
America
Cuba 8,302 0 0 $1,677,686 $0 $0 $957,607 $0 $0 $3,487,008 $0 $0 $0
North & Central
America
Dominican republic 362 0 0 $96,235 $0 $0 $53,535 $0 $0 $152,166 $0 $0 $0
North & Central
America
El salvador 89 0 0 $9,261 $0 $0 $5,815 $0 $0 $37,380 $0 $0 $0
North & Central
America
Guatemala 3,898 5,108 0 $818,173 $1,072,222 $0 $465,152 $609,585 $0 $1,636,950 $2,145,234 $0 $0
North & Central
America
Haiti 1,710 0 0 $401,120 $0 $0 $225,586 $0 $0 $718,116 $0 $0 $0
North & Central
America
Honduras 1,837 107 0 $365,766 $21,280 $0 $209,110 $12,166 $0 $771,708 $44,898 $0 $0
North & Central
America
Jamaica 1,288 119 0 $277,852 $25,604 $0 $157,531 $14,517 $0 $541,002 $49,854 $0 $0
North & Central
America
Mexico 6,456 23,581 3,018 $1,022,702 $3,735,260 $478,071 $600,831 $2,194,443 $280,864 $2,711,688 $9,904,020 $105,634 $120,724
North & Central
America
Nicaragua 8,981 0 0 $1,577,173 $0 $0 $914,638 $0 $0 $3,772,188 $0 $0 $0
North & Central
America
Panama 305 0 0 $50,850 $0 $0 $29,683 $0 $0 $128,268 $0 $0 $0
North & Central
America
Puerto Rico 50 0 0 $11,468 $0 $0 $6,463 $0 $0 $21,000 $0 $0 $0
North & Central
America
United States of
America
55,326 15,889 455,172 $10,820,332 $3,107,438 $89,019,773 $6,197,926 $1,779,952 $50,990,852 $23,236,920 $6,673,296 $15,931,006 $18,206,864
South America Argentina 0 0 12,183 $0 $0 $2,602,942 $0 $0 $1,477,191 $0 $0 $426,419 $487,336
South America Bolivia (Plurinational
State of)
802 359 0 $120,780 $54,017 $0 $71,437 $31,949 $0 $336,672 $150,570 $0 $0
South America Brazil 0 0 47,600 $0 $0 $8,127,678 $0 $0 $4,729,535 $0 $0 $1,666,000 $1,904,000
South America Chile 2,050 1,542 13,246 $224,588 $168,885 $1,450,992 $139,686 $105,040 $902,467 $861,084 $647,514 $463,600 $529,828
South America Colombia 3,413 621 0 $566,680 $103,158 $0 $330,908 $60,238 $0 $1,433,460 $260,946 $0 $0
South America Ecuador 1,546 51,958 0 $339,958 $11,424,507 $0 $192,377 $6,464,941 $0 $649,362 $21,822,234 $0 $0
South America French Guiana 329 0 0 $47,478 $0 $0 $28,256 $0 $0 $138,348 $0 $0 $0
South America Guyana 68 0 0 $10,213 $0 $0 $6,037 $0 $0 $28,350 $0 $0 $0
South America Paraguay 0 0 35,491 $0 $0 $7,965,426 $0 $0 $4,498,506 $0 $0 $1,242,189 $1,419,645
South America Peru 2,620 1,311 0 $428,189 $214,201 $0 $250,544 $125,334 $0 $1,100,526 $550,536 $0 $0
South America Suriname 31 0 0 $4,819 $0 $0 $2,843 $0 $0 $13,188 $0 $0 $0
South America Trinidad and Tobago 58 56 0 $9,922 $9,546 $0 $5,772 $5,553 $0 $24,360 $23,436 $0 $0
South America Uruguay 352 0 9,400 $109,013 $0 $2,910,308 $59,929 $0 $1,599,934 $147,882 $0 $329,000 $376,000
South America Venezuela (Bolivarian
Republic of)
2,169 480 0 $369,983 $81,936 $0 $215,319 $47,684 $0 $910,896 $201,726 $0 $0
Global totals 2,396,700 957,017 26,703,456 $408,327,232 $158,506,517 $4,503,965,422 $237,595,774 $92,566,401 $2,624,789,098 $1,006,614,070 $401,947,142 $934,620,957 $1,068,138,236
August 2012 ZALUCKI ET AL.: ECONOMIC COST OF P. xylostella 1129
... The economics of Brassicaceae cropping are significantly impacted by the diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae). It has been estimated that the worldwide cost of managing P. xylostella in vegetable crops is USD 4-5 billion annually [2,3]. China, for example, is the principal grower of cabbages (Brassica oleracea var. ...
... It is equipped with a genetic machinery that allows it to survive in significantly different environments, allowing it to be of pest status on all continents except Antarctica [5][6][7]. The most widely used management strategy in the last 50 years has been the application of insecticides [3,4,[7][8][9]. The short life cycle of DBM and a heavy reliance on insecticides has led to an expanding list of populations resistant to organochlorines, organophosphates, carbamates, pyrethroids, microbial-origin molecules and insect-growth regulators, as well as to novel mechanism insecticides [8,10,11]. ...
... Expenditure in DBM management is high due to the frequency of insecticide applications. An estimated USD 4-5 billion were spent worldwide in 2012 [3]. As previous and the present study show, in most locations, population levels often do not justify weekly insecticide sprays, much less three times within a week, as practiced in Nicaragua. ...
Article
Full-text available
The diamondback moth, Plutella xylostella (L.), is a worldwide pest of brassica crops, resistant to a large number of insecticides. As an alternative, the use of pheromone-baited traps has been proposed but farmers are yet to be convinced. In the present study, we aimed to validate the benefits of the use of pheromone-baited traps for monitoring and mass trapping in cabbage production in Central America as means of Integrated Pest Management (IPM) in comparison to calendarized insecticide sprays, which are the farmers’ current practices (FCP). Mass trapping was established in nine selected plots of cabbage in Costa Rica and Nicaragua. Average captures of males/trap/night, plant damage and net profits of these IPM plots were compared to simultaneously evaluated or historically reported FCP plots. The results indicate that in Costa Rica, trap captures did not justify the application of insecticides and average net profits increased by more than 11% when the trapping methods were implemented. In Nicaragua, IPM plots were able to reduce insecticide applications to one third of those in FCP plots. These results confirm the economic and environmental benefits of pheromone-based management of DBM in Central America.
... Chewing insects of the order Lepidoptera are among the most destructive global pests of agriculture. [1][2][3][4][5] Larvae cause damage by consuming leaf mass, cutting stems, boring into stems and stalks, mining leaves, piercing fruit, and feeding on fruit. 6 The cost of pest management can be extensive. ...
... For example, management of the most destructive global lepidopteran pest, the diamondback moth (Plutella xylostella), is estimated to cost as much as US$ 2.6-4.5 billion. 2 Lepidopteran pests continue to expand their geographic range, leading to increased injury to crops and increased management costs. [7][8][9] Moreover, lepidopteran populations continue to develop resistance to existing insecticides. ...
Article
Background: Insects of the order Lepidoptera are among the most destructive global pests causing billions of dollars in damage annually. A new class of N-arylpyrazole-4-methylpiperidines with potent activity on lepidopteran species has been discovered. Results: Compound 1 was identified in a high throughput insecticide screen to possess modest activity on the lepidopteran insect Plutella xylostella. Optimization of 1 to compound 42 resulted in a compound with excellent activity on Spodoptera exigua, Spodoptera frugiperda, and Helicoverpa zea with LC50 values of 2.8, 1.4, and 12.5 ppm respectively. While the mode of action remains unknown these compounds do not appear to work by many of the known biochemical mechanisms of insect control. Conclusion: The N-arylpyrazole-4-methylpiperidines represent a new class of insecticides with excellent activity on a broad spectrum of lepidopteran pests. Studies to date indicate the potential for a novel mode of action, however, the target site is at present unknown. This article is protected by copyright. All rights reserved.
... The diamondback moth, Plutella xylostella Linnaeus (Lepidoptera: Plutellidae), is a pest that devastates cruciferous vegetables such as pakchoi Brassica chinensis Linnaeus [1][2][3]. During the larval stage, especially the third and fourth instars, larvae gnaw on fresh leaves, severely damaging the leaves and causing significant yield losses in cruciferous vegetable production [4]. To effectively suppress the damage and keep it below the economic threshold, chemical spraying is still a crucial measure for managing the population dynamics of P. xylostella in agricultural production [5]. ...
Article
Full-text available
Changing electrical environments can influence the performance of herbivorous insects and adversely affect their control strategies. The diamondback moth, Plutella xylostella (L.), is a pest that devastates cruciferous vegetables. An age–stage, two-sex life table of P. xylostella over multiple generations was established to describe the effect of varying high-voltage electrostatic field (HVEF) exposure on their performance after the age-cohort eggs were exposed to HVEF at an intensity of 5.0 kV/cm for different durations. The results show that direct HVEF exposure adversely affected the population dynamics parameters of P. xylostella over multiple generations. In particular, the net reproduction rate, intrinsic natural increase rate, and finite increase rate of the P. xylostella population significantly decreased in the third and fifth generations under HVEF exposure for 10 min, while the mean generation time and doubling time significantly increased. Similarly, HVEF exposure for 10 min rapidly reduced the survival rate of adult P. xylostella in the first generation, and subsequently, it declined evenly and slowly. Meanwhile, the fecundity parameters of P. xylostella revealed that HVEF exposure for 10 min had the strongest inhibition effect on reproduction over five consecutive generations. In addition, HVEF exposure significantly increased the superoxide dismutase activity to produce extra hydrogen peroxide; however, increased catalase and peroxidase activity or reduced peroxidase activity triggered the accumulation of malondialdehyde in instar P. xylostella, especially after 10 min of treatment. The present findings provide experimental evidence and a theoretical basis for developing control strategies for P. xylostella under new HVEF environments.
... The damages by Plutella xylostella (Linnaus 1758) (Lepidoptera: Plutellidae) have been generating significant economic losses in the vegetables production (Barros et al. 1993;Haseeb et al. 2004;Zalucki et al. 2012). The agrotoxins is the most commonly used method for the immediate control of these insect actions, due to their practicality and quickness action with the plague population (Talekar & Shelton 1993;Valadares et al., 2020). ...
Article
Full-text available
Diamondback moth represents one of the major Brassicaceae plagues and the main current control method relies on the agrotoxins use. The search for alternative phytosanitary control methods demonstrates that the vegetal extracts have broadly studied and now represent a relevant option to control insects-plagues in small cultivation areas. Was evaluated the effect of the aqueous extract Tradescantia pallida 10% in oviposition and the feeding preference of Plutella xylostella, in laboratory conditions. That plant does not present herbivory reports, which raises the hypothesis of representing an efficient control alternative. P. xylostella couples introduced in experimentation cages for 10 days, to assess the activity of oviposition, being exposed to the botanic extract in the feeding and the oviposition substrate, with the eggs average number per day and fertility being assessed. To assess feeding, two tests developed: free choice and no choice of food source during 48 hours of evaluation. The results indicate that the aqueous T. pallida extract changes the oviposition activity of P. xylostella, reducing the average number of eggs per day and the fertility. It was also possible to observe the non-preference, regarding feeding, for substrates that were treated with the extract. The results observed in the study can contribute to amplify the small producers decision-making processes and the involved sectors regarding the choice of supplies that respect environmental and human health.
... Larvae are the damaging stage of the pest where they damage the crop by feeding on foliage parts of the crop and hinder the growth of the plant leading significant reduction in yield. DBM is known to cause yield loss from 31 percent (Abraham and Padmanabhan, 1968) to 100 percent (Cardleron and Hare, 1986) and the conservative estimate of total costs for managing this pest is estimated to be US$4 billion to US$5 billion (Zalucki et al., 2012). ...
Article
A leaf dip technique of bioassay for mortality of DBM larvae was conducted in laboratory condition with room temperature of 25±2°C, relative humidity of 80±3% and 13:11 ratio of Light: dark period at Department of Entomology, Agriculture and Forestry University, Rampur, Chitwan with three replication and eight treatments; i.e. i) Lipel (Bacillus thuriengiensis var. kursataki) 2gm/l, ii) Racer (Beauveria bassiana 1.15% WP) 2gm/l, iii) Derisom (Fractions of Derris indica) 2ml/l, iv) Anosom (Extracts of Annona spp. 1%) 2ml/l, v) Neemix (Neem oil 60% w/w, Azadiractin content less than 300 ppm) 2ml/l, vi) Anthsuper (Chloropyrifos 16% A.I. + Alphacypermethrin 1%EC (w/w) 2ml/l, vii) cow urine (1:5 with water) and viii) control (water spray) in Completely Randomized Design (CRD). The larval mortality was taken after 3, 9, 21, 33, 57 and 93 hours after the treatment application. The larval mortality was found to be significantly higher in Anthsuper treated with 100% mortality of larvae within 33 hours after treatment application followed by cow urine, botanicals (Neemix, Derisom and Anosom) and microbials (Racer and Lipel) where the larval mortality over control was found to ranging from 10% to 47.57% during the experimental period. The larval mortality was 47.57% for Cow urine and Neemix followed by 38.14% for Anosom, 33.29% for Racer, 28.57% for Derisom and 19% for Lipel.it is concluded that chemical pesticide Anthsuper is superior for immediate control of the pest but considering the safety of environment and human health; for long-term control of the pest botanicals and microbials would be more efficient.
... The diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), is a worldwide major insect pest of cruciferous vegetables, such as cabbage, cauliflower, and many other important economic food crops [20][21][22]. The total global economic cost of its destruction and management is estimated at USD 4-5 billion per year [23]. Due to the extensive use of chemical pesticides, all major kinds of insecticides have been ineffective against P. xylostella, making it challenging to control [20]. ...
Article
Full-text available
In insects, male accessory gland proteins (ACPs) are important reproductive proteins secreted by male accessory glands (MAGs) of the internal male reproductive system. During mating, ACPs are transferred along with sperms inside female bodies and have a significant impact on the post-mating physiology changes of the females. Under sexual selection pressures, the ACPs exhibit remarkably rapid and divergent evolution and vary from species to species. The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major insect pest of cruciferous vegetables worldwide. Mating has a profound impact on the females' behavior and physiology in this species. It is still unclear what the ACPs are in this species. In this study, two different proteomic methods were used to identify ACPs in P. xylostella. The proteins of MAGs were compared immediately before and after mating by using a tandem mass tags (TMT) quantitative proteomic analysis. The pro-teomes of copulatory bursas (CB) in mated females shortly after mating were also analyzed by the shotgun LC-MS/MS technique. In total, we identified 123 putative secreted ACPs. Comparing P. xylostella with other four insect ACPs, trypsins were the only ACPs detected in all insect species. We also identified some new insect ACPs, including proteins with chitin binding Peritrophin-A domain , PMP-22/ EMP/ MP20/ Claudin tight junction domain-containing protein, netrin-1, type II in-ositol 1,4,5-trisphosphate 5-phosphatase, two spaetzles, allatostatin-CC, and cuticular protein. This is the first time that ACPs have been identified and analyzed in P. xylostella. Our results have provided an important list of putative secreted ACPs, and have set the stage for further exploration of the functions of these putative proteins in P. xylostella reproduction.
... The larvae attack the leaves, decreasing the plant's photosynthetic area, growth, and productivity. Due to control failures and insecticide resistance, the cost of P. xylostella management is estimated at USD 4 to 5 billion annually [8]. Therefore, the extensive use of pesticides to control this pest represents a considerable risk to natural enemy populations [9]. ...
Article
Full-text available
We evaluated the efficacy and residual toxicity of nine commercial insecticides on Plutella xylostella and their selectivity to the predator ant Solenopsis saevissima under laboratory and field conditions. First, to test the insecticides' effectiveness and selectivity, we conducted concentration-response bioassays on both species, and the mortalities were recorded 48 h after exposure. Next, rapeseed plants were sprayed following label rate recommendations in the field. Finally, insecticide-treated leaves were removed from the field up to 20 days after application and both organisms were exposed to them as in the first experiment. Our concentration-response bioassay indicated that seven insecticides caused mortality ≥80% of P. xylostella: bifenthrin, chlorfenapyr, chlorantraniliprole, cyantraniliprole, indoxacarb, spinetoram, and spinosad. However, only chlorantraniliprole and cyantraniliprole caused mortality ≤30% of S. saevissima. The residual bioassay indicated that four insecticides had a long-lasting effect, causing mortality of 100% to P. xylostella 20 days after application: chlorantraniliprole, cyantraniliprole, spinetoram, and spinosad. For S. saevissima, bifenthrin caused mortality of 100% during the evaluated period. Additionally, mortality rates below 30% occurred four days after the application of spinetoram and spinosad. Thus, chlorantraniliprole and cyantraniliprole are safe options for P. xylostella management since their efficacy favor S. saevissima.
Article
Brassica growers rely on insecticides to control the diamondback moth (DBM) Plutella xylostella (L.), resulting in cases of insecticide resistance and control failure. The ring-legged earwig Euborellia annulipes (Lucas) is found in brassica fields and may prey upon DBM eggs, larvae, and pupae. Therefore, preservation of E. annulipes in brassica crops could enhance DBM control, and may help with DBM insecticide resistance management. The insecticides azadirachtin, chlorantraniliprole, cyantraniliprole, deltamethrin, indoxacarb, methomyl, spinosad, and teflubenzuron were evaluated to assess mortality of E. annulipes adults and DBM larvae when exposed to insecticide dry residues, and predation rate upon DBM larvae and pupae. Euborellia annulipes exhibited survival >98% to all tested insecticides when exposed to label rates used on brassica crops against DBM. The highest mortality of DBM larvae confined on insecticide dry residue was 61% after 24 h exposure. This mortality significantly increased up to 92% when E. annulipes was present in the same period. Female of E. annulipes showed a preference for DBM larvae over pupae irrespective of ratio availability and insecticide combinations. When only larvae or pupae were available, up to nine larvae or four DBM pupae were consumed within 24 h. At the label rate for spraying brassica crops, all tested insecticides were compatible with E. annulipes and the predator added significant mortality to DBM larvae in the presence of insecticide residue. The findings reveal opportunities for integrating E. annulipes as a biological control agent into management programmes for DBM that cannot effectively rely on insecticides alone.
Article
Elucidating the genetic basis of local adaption is one of the important tasks in evolutionary biology. The Qinghai-Tibet Plateau has the highest biodiversity for an extreme environment worldwide, and provides an ideal natural laboratory to study adaptive evolution. The diamondback moth (DBM), Plutella xylostella, is one of the most devastating pests of the global Brassica industry. A highly heterozygous genome of this pest has facilitated its adaptation to a variety of complex environments, and so provides an ideal model to study fast adaptation. We conducted a pilot study combining RNA-seq with an age-stage, two-sex life table to study the effects of oxygen deprivation on DBM. The developmental periods of all instars were significantly shorter in the hypoxic environment. We compared the transcriptomes of DBM from Fuzhou, Fujian (low-altitude) and Lhasa, Tibet (high-altitude) under hypoxia treatment in a hypoxic chamber. Some DEGs are enriched in pathways associated with DNA replication, such as DNA repair, nucleotide excision repair, base excision repair, mismatch repair and homologous recombination. The pathways with significant changes were associated with metabolism process and cell development. Thus, we assumed that insects could adapt to different environments by regulating their metabolism. Our findings indicated that although adaptive mechanisms to hypoxia in different DBM strains could be similar, DBM individuals from Tibet had superior tolerance to hypoxia compared with those of Fuzhou. Local adaptation of the Tibetan colony was assumed to be responsible for this difference. Our research suggests novel mechanisms of insect responses to hypoxia stress.
Article
The frequent and extensive use of insecticides leads to the evolution of insecticide resistance, which has become one of the constraints on global agricultural production. Avermectins are microbial-derived insecticides that target a wide number of insect pests, including the diamondback moth Plutella xylostella, an important global pest of brassicaceous vegetables. However, field populations of P. xylostella have evolved serious resistance to avermectins, including abamectin, thereby threatening the efficiency of these insecticides. In this study, a novel valine to isoleucine mutation (V263I) was identified in the glutamate-gated chloride channel (GluCl) of field P. xylostella populations, which showed different levels of resistance to abamectin. Electrophysiological analysis revealed that the V263I mutation significantly reduced the sensitivity of PxGluCl to abamectin by 6.9-fold. Genome-modified Drosophila melanogaster carrying the V263I mutation exhibited 27.1-fold resistance to abamectin. Then, a knockin strain (V263I-KI) of P. xylostella expressing the homozygous V263I mutation was successfully constructed using the CRISPR/Cas9. The V263I-KI had high resistance to abamectin (106.3-fold), but significantly reduced fecundity. In this study, the function of V263I mutation in PxGluCl was verified for the first time. These findings provide a more comprehensive understanding of abamectin resistance mechanisms and lay the foundation for providing a new molecular detection method for abamectin resistance monitoring.
Technical Report
Full-text available
Cabbage is one of the most important vegetable crops in Indonesia. Cabbage production improvement in Indonesia is constrained by various factors including crop damage by two main pests: diamondback moth (DBM), Plutella xylostella, and cabbage head caterpillar (CHC), Crocidolomia pavonana. Attacks by these two pests together can cause complete cabbage yield loss if appropriate control measures are not undertaken, especially during the dry season. This study updates that of Rauf et al. (1993) and was conducted to evaluate current pest control practices implemented by brassica growers in Indonesia to provide the necessary baseline for calculation of the possible role of Bt transgenic brassicas in the future. Work on the technical and environmental feasibility of Bt brassicas will take place under a Programme for Biosafety Systems project from 2005-2008. The main activity of the current study was a survey of pesticide use by cabbage growers in West Java. As supporting information, literatures on resistance of cabbage pests to insecticides, pesticide residues in cabbage, and IPM programmes for cabbage pests were also surveyed and discussed. The survey of pesticide use by cabbage farmers was conducted in cabbage producing areas in Cianjur/Sukabumi, Bandung, and Garut regencies, West Java during September-October 2004. Two sub-districts in each of the three districts were selected as survey areas and in each sub-district 20 farmers were selected. The respondents were randomly selected among cabbage farmers in study locations. The survey was carried out by one-to-one interviews using a structured questionnaire. Results of the survey show that, consistent with the general understanding, P. xylostella and C. pavonana were the most prevalent pest problems faced by respondents and insecticides were intensively used to control the pests (4 to 15 pesticide applications per crop season). Season-long IPM training through farmer field schools (FFS) had been undertaken by 2.5% to 25% of farmers depending on the district. Despite these IPM extension programmes, with c.2,500 vegetable farmers trained in IPM through FFS since 1989, about 90% of respondents still carry out pesticide spraying on a scheduled basis or on the simple presence of the pests and not on the use of economic threshold levels (ETLs). Most insecticides used by respondents are neurotoxicants which can harm human health and kill beneficial organisms. Very few farmers (only about 5%) used the sprayed microbial insecticide Bacillus thuringiensis (Bt) or implemented IPM components/ methods in cabbage pest control practices. Pesticide expenses mostly contributed 10%-30% of total cabbage production costs and for more than two-thirds of respondents spending on insecticides alone accounted for 80-100% of the total pesticide costs. Most farmers are aware of negative impacts of pesticides on human health and beneficial organisms but in practice not all farmers followed the rules of safe use and storage of pesticides and in some cases safety precautionary measures were not duly observed. Available literature in Indonesia indicates that P. xylostella is capable of developing resistance to some insecticides, including Bt LC50s of deltamethrin and profenofos to P. xylostella larvae from Lembang (West Java) were reported to increase 16.9- and 2570-fold, respectively, in 2001 compared with that in 1988, while LC50s of the Bt formulation Dipel WP in 1991, 1995 and 2001 were 1.6, 13.0 and 30.2 times higher than that in 1983. Despite intensive insecticide application against cabbage head caterpillar C. pavonana, published reports on resistance of this pest to insecticides are not available. Data on pesticide residues in cabbage are still very scarce. There is no routine government monitoring of residues, even for the c$US12 mill of cabbage exported annually. One study in Bogor (West Java) found that residues of the tested pesticides on cabbage were still below their maximum residue limits. The population of DBM in some major cabbage growing areas can be adequately curbed by its larval-pupal parasitoid Diadegama semiclausum Hellen (Hymenoptera: Ichneumonidae) when insecticides are not used intensively. In areas where CHC is also prevalent, farmers normally rely heavily on synthetic insecticides to control the pest because there are no effective biological control or other non-chemical measures readily available against CHC. Intensive use of insecticides against CHC will badly interfere with the activity of D. semiclausum which in turn may cause the collapse of cabbage IPM at farmer level. In the authors’ opinion, given the relatively poor uptake of knowledge-intensive IPM programmes and increasing problems with conventional insecticide resistance, effective Bt cabbages could play a very useful role in suppressing DBM and perhaps reducing the impact of CHC. The human health, residue and cost savings could be considerable. However, the efficacy of Bt transgenic plants against CHC needs be established. Given the propensity of DBM to develop resistance to insecticides, including to sprayed Bt formulations, in order to maximize the chances of sustainability of such an approach it would be important to ensure that more than one previously un-used and non-cross resisting toxins were used i.e. a stacked gene approach.
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Full-text available
This study investigated Cameron Highlands cabbage farmers' knowledge and practice of pest management, particularly the use of pesticides against Plutella xylostella. A survey of 99 cabbage farmers was conducted in five different zones in the Cameron Highlands. This survey and others conducted by previous researchers showed little change in farming systems over the past decade. P. xylostella remains the major pest in cabbage and more than 90% of farmers use pesticides for control. There are 11 types of insecticides used to control this pest and each farmer usually uses 3–4 types of insecticide to control the pest over a season. Both high and low toxicity pesticides are commonly used. There is a significant difference in pesticide spray frequency during wet and dry seasons, with more frequent sprays during the wet season. The study also revealed that more than 50% of farmers observe 10–14 day pre-harvest intervals, while 4% observe a pre-harvest interval of only 1–4 days. Wholesale markets still play an important role in marketing of fresh produce despite the increasing role of supermarkets in the food chain. Current regulations on pesticide residue monitoring were only applied at the farm gate and any penalties are directed at the growers. The origin of fresh produce could only be traced up to the wholesaler. Therefore, it is less effective to impose pesticide monitoring at the retailer level, as the origin of the produce could not be traced, nor could feedback to producers be achieved.
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Full-text available
Studies on Seasonal Abundance of Diamondback Moth Plutella Xylostella (Lepidoptera: Yponomeutidae) On Cauliflower Crop The studies on seasonal abundance of diamondback moth Plutella xylostella were conducted in two years 2004-2005 and 2005-2006. Survey data of three localities of Aligarh district showed that initial infestation by P. xylostella occurred when the farmers started transplantation of cauliflower seedlings, the density of P. xylostella ranged between 0.90 to 2.38 and 0.27 to 5.84 larvae and pupae/plant in I week of July, 2004 and 2005, respectively, and the rate of parasitization was quite low. Temperature and humidity recorded maximum and minimum i.e. 24.15° to 32.91°C and 68.60 to 91.30 percent, respectively. Population build up is usually observed in II to IV week of September. Cotesia plutellae was found to be a dominant larval parasitoid while, Oomyzus sokolowskii parasitized relatively few pupae of P. xylostella. 34.77°C significantly (p < 0.01) enhanced the population of DBM also on 8th September, 8th October, 2004 and 26th January, 2005. Rainfall negatively affected the DBM population in 2004-2005 and 2005-2006.
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Full-text available
Brassicas comprise a major group of vegetable crops in Zhejiang Province, China and south- east Queensland, Australia. In Zhejiang, heavy reliance on chemical control to manage insect pests in brassica vegetable production has resulted in insecticide resistance, increased costs of pest control and insecticide residues hazardous to human health. In southeast Queensland, reliance on chemical control has also resulted in increased cost of pest control, control fail- ures due to insect resistance and reduced profits. To improve sustainable production of bras- sica vegetables in the two regions, a group of Chinese and Australian scientists have under- taken a joint project to develop practical integrated pest management (IPM) strategies for these crops. In both regions, major efforts have been made to evaluate the complexes of endemic natural enemies under different pest management practices, and to conserve and enhance these natural enemies as the central elements of effective management programs. In Zhejiang, field trials were conducted across crops, seasons and localities to test and improve an IPM system that emphasized the use of proven action thresholds for different crop growth stages and strategic application of selective insecticides to promote the impact of natural enemies. Com- pared with conventional methods, IPM practices were associated with substantially higher natural enemy activity, a 20-70% reduction in input of insecticides, and no yield loss. The improved IPM system has been implemented to various degrees in major vegetable produc- tion areas in Zhejiang, and has improved the safety and profitability of production. In southeast Queensland, as an important part of the IPM development and implemen- tation effort, a three-year experimental field study was conducted to evaluate the impact of endemic natural enemies on independent farms practicing a range of pest management strate- gies. Natural enemy impact was greatest on farms adopting IPM and least on farms practicing insecticide intensive conventional pest control strategies. On IPM farms, the contribution of natural enemies to pest mortality permitted the cultivation of marketable crops with no yield loss but with an average of 70% less insecticide inputs compared to conventional farms.
Article
Traps baited with a sex pheromone lure were placed in two fields located in Pathum Thani Province in central Thailand to estimate the seasonal trend in population density of the diamondback moth, Plutella xylostella, over a two year periods. Although a large number of moths were captured all year round regardless of different climatic conditions such as dry and rainy seasons, the population density was clearly different between the two fields, indicating that the number of emerging moths varied form place to place even in the same season. The population density declined sharply with the harvest of cruciferous vegetables, and recovered several weeks after the harvest. Forewing length of male moths captured in Thailand were constantly short through the year and about the same size as those of males found only in mid-summer in Japan.
Article
1. We use an individual-based model describing the life of a monarch butterfly, which utilises milkweeds both aggregated in patches and scattered across the wider landscape as a substrate for laying eggs. The model simplifies the metapopulation of milkweed habitat patches by representing them as a proportion of the overall landscape, with the rest of the landscape considered matrix, which may contain some low density of milkweed plants. 2. The model simulates the number of eggs laid daily by a butterfly as it searches for hosts. The likelihood of finding hosts is related to the density of plants and the search ability of the butterfly. For an empty matrix, remaining in a habitat patch results in more eggs laid. However individuals that are good searchers have almost equivalent success without remaining in a habitat patch. These individuals are most affected by the presence of hosts in the matrix. 3. Given realistic values of habitat patch availability, our model shows that the presence of plants at a low density in the matrix has a substantial impact on the number of eggs laid; removing these plants can reduce lifetime potential fecundity by ca. 20%. These results have implications for monarch butterflies inhabiting agricultural landscapes, in which genetically modified soybean that is resistant to herbicides has resulted in the decimation of milkweeds over large areas.
Article
Diamondback moth, Plutella xylostella (L.), is the most destructive pest of crucifer crops in the Philippines. Life cycle, population dynamics and biological control with the larval parasitoid Diadegma semiclausum have been studied (1988-90) in the mountains of Northern Luzon. One generation of the diamondback moth requires 24.7 days, therefore about 15 generations of the pest may occur during 1 year. The average life expectancy of the females is 16.7 days, during which an average of 233 eggs (maximum 639) are deposited. The continuous monitoring of the diamondback moth field population with light and pheromone traps proved that during the rainy season (June- October) only 5-10 moths/week were found; during population peaks (January and February) almost 3000 moths/week were found. Only one natural enemy - Cotesia plutellae (Kurdjumov) has a certain importance in controlling the pest. The parasitism reaches 70% but its efficacy is reduced by hyperparasitism to 80% by a group of six hymenopterans. Starting in March 1989 D. semiclausum was imported from Taiwan. The performance of D. semiclausum was evaluated in field experiments with screen- covered cabbage plots. The parasitism reached 95%, and in two of three experiments the yield of cabbage was significantly higher than in the control. In an open-field experiment the parasitoid was established with rates of parasitism from 12 to 15% increasing to 64% at harvest time.
Article
Three major primary parasitoids of the diamondback moth, Plutella xylostella (L.), are found in the Cameron Highlands, Malaysia. Cotesia plutellae (Kurdjumov) was discovered in the early 1970s, Diadegma semiclausum (Hellén) and Diadromus collaris (Gravenhorst) were introduced in the mid 1970s from New Zealand and Australia. Field studies in the early 1980s showed that C. plutellae was the dominant parasitoid. This was contrary to laboratory studies which showed that D. semiclausum was an intrinsically superior parasitoid. In the Cameron Highlands, farmers sprayed insecticides frequently, often at concentrations far exceeding recommended dosages. In 1987, Singapore imposed restrictions on excessive levels of pesticide residues in crucifers. This together with high levels of insecticide resistance in the DBM resulted in farmers switching to the use of Bacillus thuringiensis, resulting in an unprecedented development for the management of diamondback moth. Even with reduced usage of chemical insecticides farmers were able to harvest good crops. Reduction in use of chemical insecticides allowed the primary parasitoids to realize their potential. The impact of biological control is manifested in: a) lower population of DBM despite less usage of insecticides; b) D. semiclausum became the dominant parasitoid; c) farmers realized that they need not be dependent on insecticides. Hence after more than 10 years, the impact of D. semiclausum, which was masked by excessive insecticide usage, was realized. Other parasitoids, predators and microbial agents probably act in consonance to suppress the DBM population. The experience in the Cameron Highlands emphasized the central role of parasitoids in managing diamondback moth, The strategy in managing this pest is to build up a core of effective parasitoids and supplement the action of parasitoids with use of B. thuringiensis when necessary.