). Incidence of red spider mite (Tetranychus urticae Koch) on okra (Abelmoschus esculentus (L.) Moench) and their sustainable management

Abstract

Okra (Abelmoschus esculentus L.) is an annual vegetable crop grown in the sub-Himalayan region of north east India throughout the year except winter. The crop is susceptible to various insect and mite pests of which red spider mite, Tetranychus urticae Koch. causes heavy damage. So, a study on its occurrence and sustainable management was carried out. The pest was active throughout the growing period with a peak population (6.18 mites/leaf) during 23 rd SMW (last week of May) in the pre-kharif crop. Highest population (7.56/leaf) was found on the 42 nd SMW (first week of October) in the post kharif crop. Sudden fall of population was found in last week of June because of heavy rains. The incidence of mite population always remained higher on the upper canopy of the plant. Weekly population counts on mites showed non-significant positive correlation (p=0.05) with temperature, maximum relative humidity, total rainfall and significant positive correlation with minimum and average relative humidity. Eight treatments viz., microbial insecticide (toxin), avermectin (Vertimec 1.9 EC) @ 1.0 ml/ L; botanical insecticide azadirachtin (neemactin 0.15 EC) @ 2.5 ml/L,; botanical extracts, Spilanthes paniculata flower extracted in methanol @ 1.0% and 5.0% and mixed formulation like neem and floral extract of Spilanthes 5% (@ 2.5 ml and 50 ml/L were evaluated and compared with the ability of Sulphur (Sulfex 80 WP) @ 5g/ L and Fenazaquin (Magister 10EC) @ 2ml/L for the management of the mite pest. Fenazaquin resulted in the best suppression of mite population (79.24 % suppression), closely followed by avermectin (76.40 % suppression). Among bio-pesticides, avermectin and combination of neem with Spilanthes gave better results recording more than 70 % suppression. Neem and Spilanthes individually did not produce good results but when used as a mixture they recorded better results (70.66 % suppression).

Full text

Current Biotica 7(1&2): 40-50, 2013 ISSN 0973-4031
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Incidence of red spider mite (Tetranychus urticae Koch) on okra (Abelmoschus
esculentus (L.) Moench) and their sustainable management
Sunil Kr. Ghosh
Department of Agricultural Entomology, Uttar Banga Krishi Viswavidyalaya (University),
Pundibari, Cooch Behar, West Bengal-736165, India
E-mail: sunil_ent69@yahoo.in
ABSTRACT
Okra (Abelmoschus esculentus L.) is an annual vegetable crop grown in the sub-
Himalayan region of north east India throughout the year except winter. The crop is susceptible
to various insect and mite pests of which red spider mite, Tetranychus urticae Koch. causes
heavy damage. So, a study on its occurrence and sustainable management was carried out. The
pest was active throughout the growing period with a peak population (6.18 mites/leaf) during
23rd SMW (last week of May) in the pre-kharif crop. Highest population (7.56/leaf) was found
on the 42nd SMW (first week of October) in the post kharif crop. Sudden fall of population was
found in last week of June because of heavy rains. The incidence of mite population always
remained higher on the upper canopy of the plant. Weekly population counts on mites showed
non-significant positive correlation (p=0.05) with temperature, maximum relative humidity, total
rainfall and significant positive correlation with minimum and average relative humidity. Eight
treatments viz., microbial insecticide (toxin), avermectin (Vertimec 1.9 EC) @ 1.0 ml/ L;
botanical insecticide azadirachtin (neemactin 0.15 EC) @ 2.5 ml/L,; botanical extracts,
Spilanthes paniculata flower extracted in methanol @ 1.0% and 5.0% and mixed formulation
like neem and floral extract of Spilanthes 5% (@ 2.5 ml and 50 ml/L were evaluated and
compared with the ability of Sulphur (Sulfex 80 WP) @ 5g/ L and Fenazaquin (Magister 10EC)
@ 2ml/L for the management of the mite pest. Fenazaquin resulted in the best suppression of
mite population (79.24 % suppression), closely followed by avermectin (76.40 % suppression).
Among bio-pesticides, avermectin and combination of neem with Spilanthes gave better results
recording more than 70 % suppression. Neem and Spilanthes individually did not produce good
results but when used as a mixture they recorded better results (70.66 % suppression).
KEY WORDS: Avermectin, bio-pesticides, okra, organic farming, Spilanthes, Tetranychus
urticae
INTRODUCTION
Okra (Abelmoschus esculentus L.) is
an annual crop that belongs to the family
Malvaceae and one of the most important
vegetable crops grown in various parts of
tropical and sub-tropical areas of the globe.
Though okra finds its origin in South Africa,
India stands top in area and production, with
3.58 lakh ha area,35.24 lakh tones
production and a productivity of 9.8 t/ha
(Anon., 2005). In the sub-Himalayan region
of north east India, okra is cultivated on a

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commercial scale but insect and mite pest
damage constitutes a limiting factor in
successful production (Ghosh et al., 1999).
The crop is susceptible to various insect and
mite pests of which red spider mite,
Tetranychus urticae Koch. formerly known
as Tetranychus cinnabarinus Boisd.
(Tetranychidae : Acarina) is most
predominant. Pillai and Palaniswani (1983)
worked out cassava and found that a
complex of four species of mite viz.,
Eutetranychus orientalis, Oligonychus
biharensis, Tetranychus cinnabarinus and T.
neocaladonicus caused significant yield
reduction of 17.33 %. The outbreak of this
pest is assumed to be the consequences of
frequent and indiscriminate use of toxic
chemicals, especially pyrethroid insecticides
by the vegetable growers (Dobson et al.,
2002). Moreover, warm and dry weather is
favourable for the multiplication and spread
of this pest (Jeppson et al., 1975).
In India, it has been reported as one
of the important pests of vegetable crops
(Gupta, 1985; Singh et al., 1987) Anitha and
Nandihali (2008) reported that incidence of
mite on summer crop commenced from 16th
standard week (2.12 mites/3leaves) and peak
infestation was on 2nd week of May (14.61
mites/3leaves) and on kharif crop peaked
during 4th week of October (29.25
mites/3leaves). Puttaswamy and Channa
Basavanna (1980) reported that population
of mite attained peak during May-June. The
first sight of infestation by red spider mite is
usually chlorotic, stippled appearance on the
leaves. As the mites feed on the underside
of the leaves, they remove leaf cell contents,
including the chlorophyll. Without the
chlorophyll, those empty cells appear
whitish or bronze. Heavily infested leaves
turn completely pale, dry up, and fall off.
Large populations can severely defoliate
plants. Yield may be greatly reduced as the
plants become weak and photosynthetic
activity is seriously hampered.
The use of conventional insecticides
and synthetic pyrethroids based on crop
stage has proved to be the most effective
pest control in okra (Krishnakumar and
Srinivasan, 1987). Kumar et al., (2007)
reported that methanolic extract of neem and
karanj at 1% concentration proved 78.6 and
71.9 % control of Tetranychus sp.,
respectively at laboratory conditions.
Avermectin are natural compounds
produced by soil Actinomycetes,
Streptomyces avermitilis that used as
acaricide. It provided excellent initial and
residual control of immature and adult mites
on a number of crops (Muraleedharan,
1993). Several workers reported the
excellent efficacy of abamectin in mite
control. It is widely used in the control of
Polyphagotarsonemus latus, Tetranychus
cinnabarinus, Acephylla theae, Calacarus
carinatus, Eriophyes discoridis, Aculops
lycopersici on castor, cotton, chilli, tea
tomato and cucumber crops in different parts
of the world (Huengens and Degheele, 1986;
Donatoni et al., 1988; Zie et al., 1992;
Muraleedharan, 1993). The control of this
pest through synthetic pesticides particularly
during the fruit bearing stage is rather
difficult as the fruits are harvested at
frequent intervals and this result in the
possibility to retain toxic residues in the
fruits which may cause health hazards.

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Various tests were carried out with
pesticides from different origins for
developing a safe management strategy for
this notorious mite pest.
Acharya et al., (2002) studied the
efficacy of new insecticides imidacloprid,
abamectin and reported the new molecules
evaluated were safer to lady bird beetles. In
many cases, our farmers are misguided by
spraying synthetic insecticides to combat
this pest which are harmful to our health and
environment. Documentation of the
population abundance and spatial
distribution of this pest in vegetables and
selection of newer acaricides would open up
new scope for our farmers to combat spider
mites in vegetable cultivation. Under the
present investigation an attempt has been
made to formulate suitable control measure
with the use of microbial toxin Streptomyces
avermitilis, botanical extracts of Spilanthes
paniculata Wall. ex DC. and neem based
formulation.
MATERIALS AND METHODS
Studies were conducted in the
Instructional Farm of Uttar Banga Krishi
Viswavidyalaya (State Agricultural
University) at Pundibari, Coochbehar, West
Bengal, India for two years during 2010-11.
The experimental area is situated in the sub-
Himalayan region of north-east India. This
so called terai zone is situated between
25057’ and 270 N latitude and 88025’ and
89054’ E longitude. The soil of the
experimental field was sandy loam with pH
value 6.9. The climate of this zone is
subtropical humid with a short winter spell
during December to February.
Seasonal incidence of red spider mite:
The okra variety ‘Nirmal-101’ was
grown round the year except winter when
okra cultivation is not possible in this area,
during 2010-2011 in both years under
recommended fertilizer levels (120:60:60 kg
NPK/ha ) and cultural practices in 4.8 m x
4.5m plots at a spacing of 75 cm x 35 cm.
The treatments were replicated five times in
a Randomized Block Design (RBD). The
total mite population per leaf from top,
middle and bottom leaves from five
randomly selected plants per replication was
recorded with the help of a magnifying glass
at seven days (Standard Meteorological
Week) interval during okra growing seasons
in both the years. Data obtained over two
years were presented graphically with
important weather parameters viz.
temperature, relative humidity. Correlation
co-efficient (r) was worked out between
incidence of mite and important weather
parameters during the period to find out
influence of weather on population
fluctuation.
Control of red spider mite:
This two year (2010-2011) study was
conducted at the instructional farm of Uttar
Banga Krishi Viswavidyalaya (State
Agricultural University) at Pundibari,
Coochbehar, West Bengal, India.The okra
variety ‘Nirmal-101’ was grown during the
post-kharif (mid August) season in both
years under recommended fertilizer levels
(120:60:60 kg NPK/ha) and cultural
practices in 4 m x 5m plots at a spacing of
75 cm x 35 cm. The treatments were

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replicated three times in a Randomized
Block Design (RBD).
One microbial insecticide (toxin),
avermectin (Vertimec 1.9 EC) @ 1.0 ml/ L;
one botanical insecticide azadirachtin i.e.
neem (neemactin 0.15 EC) @ 2.5 ml/L; one
botanical extracts, Spilanthes paniculata
flower extract @ 1.0% and 5.0% and one
treatment containing mixture of neem and
floral extract of Spilanthes 5% (@2.5 ml and
50 ml/L were evaluated against mite pest
These were compared with the ability of
Sulphur (Sulfex 80 WP) @ 5g/ L and
Fenazaquin (Magister 10EC) @ 2ml/L to
control the mite pest, Tetranychus urticae
Koch. These acaricides are recommended
for use against this mite pest.
The Spilanthes paniculata floral
parts were extracted in methanol as follows.
After washing with water, the plant parts
were powdered in a grinder. The powder (50
g) samples of each tested plant were
transferred separately to a conical flask (500
ml) and dipped in 250 ml methanol. The
material was allowed to stand for 72 hours at
room temperature with occasional stirring.
After 72 hours the extract was filtered
through Whatman 42 filter paper and
residues were washed twice with methanol.
Four sprays at 10 day intervals were
made, starting with the initiation of
infestation. Mite population densities were
recorded 3, 6, and 9 days after each
spraying. The total mite population per leaf
from top, middle and bottom leaves from
five randomly selected plants per replication
was recorded. The results were expressed as
mite population suppression (%) compared
to densities recorded on the control
treatment. Percent reduction of mite
population over control was calculated by
the following formula (Abbott, 1925):
Po − Pc
Pt = ----------------------- ×
100
100 − Pc
Where, Pt = Corrected mortality, Po =
Observed mortality and Pc = Control
mortality. Data were analyzed by using
INDO-STAT- software for analysis of
variance following randomized block design
(RBD) treatment means were separated by
applying CD Test (critical difference) at 5 %
level of significance.
The fruits were harvested at frequent
intervals when they attained marketable size.
The yield of marketable produce was
calculated in different years separately on
the basis of fruit yield per plot and converted
to tons per hectare.
RESULTS AND DISCUSSION
Seasonal incidence of red spider mite
Analysis of pooled mean data for the
two years during the okra growing period (9
SMW to 45 SMW) of the year on mite
infestation revealed that the pest was active
throughout the growing period except 9-12
SMW i.e., last week of February to second
week of March (Fig 1 and Fig. 2). However,
population appeared during middle of March
and remained very low up to middle of April
and thereafter increased gradually with the
rise of temperature. Pest population reached
high (6.18 mites/leaf) during 23rd SMW (last
week of May) and thereafter started decline
with the onset of monsoon and heavy
rainfall, and this tendency was continued up
to 36 SMW (last week of August). After
rainy season, again pest population
increased and reached highest population

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(7.56/leaf) on the 42nd SMW (first week of
October) when the average temperature,
average relative humidity and weekly total
rainfall were 28.650c, 76.55% and 23.80
mm. respectively. However, mite was most
active during May i.e., 22-24 SMW and
September-October i.e., 40-43 SMW. There
was a sudden fall of population was found
with the heavy rains (weekly total 201.95
mm) during monsoon in 25th SMW (last
week of June) and continued up to end of
August.
Fig. 2 represents the incidence of
mite population on upper, middle and lower
canopy within the okra plant. The incidence
of mite population always remained higher
on the upper canopy of the plant as
compared with the middle and lower
canopy. During 23 SMW (end of May) and
42 SMW (early October) the mite
population on the upper canopy of the plant
reached very high as 8.33 mites/L and11.89
mites/L respectively as compared with the
middle canopy 5.33mites/L and 5.67mites/L
and with the lower canopy 3.67 mites/L and
5.12 mites/L respectively. The lower canopy
always contained low mite incidence and
only similar trend of incidence with the
middle canopy was found during 16-17
SMW (late April month) and 32-33
SMW(early August) month.
Fig. 3 revealed that the mites were
most densely populated in the upper canopy
(54.32% population) followed by middle
canopy (28.79% population) and lower
canopy (16.89% population). This result
implies that mites were most densely
populated in the young and new leaves of
okra plant. In a study on the spatial
distribution of mites in brinjal plants, Dutta
et.al., (2011) reported that mites were most
densely populated in the upper canopy
(44.24%) followed by middle (30.57%) and
lower canopy (25.19%). Howerever,
Fitzgerald et. al.,(2008) observed reverse
results while studying spatial distribution on
different mite species in strawberry plants
and reported that T. urticae was most
abundant on older leaves i.e., lower canopy.
This variation in result can be explained by
the fact that mite population usually moves
from lower canopy towards upper canopy
and when food reserve in the lower canopy
becomes scanty the population moves
towards upper.
Correlation between mite
infestations with important weather
parameters (Table 1) showed that population
had non-significant positive correlation with
temperature (maximum, minimum and
average), maximum relative humidity and
weekly total rainfall where as significant
positive correlation with minimum and
average relative humidity. The population
had a non-significant negative correlation
with temperature gradient. The mite
population showed a tendency to increase
with the increase of high temperature and
relative humidity.
Management of red spider mite
Variation in relative efficacy of
different treatments and their persistency at
different days after treatment (DAT) on
suppression of mite (Tetranychus urticae)
population was significant. The results were
presented in table 2. Among the seven
pesticides evaluated (Table 2) under the

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present investigation fenazaquin treatment
resulted in the best suppression of mite
population (79.24 % suppression), closely
followed by microbial toxin, avermectin
(76.40 % suppression). However among the
bio-pesticides including plant extracts,
avermectin was found most effective closely
followed by mixed formulation of Neem
(Azadiractin) and Spilanthes (70.66 %
suppression). From overall observation it
was revealed that bio-pesticides like
microbial tixin avermectin and combination
of neem with Spilanthes floral part extracts
gave better results recording more than 70 %
suppression of mite population. Neem and
Spilanthes individually did not produce
good results (only 43.72 and 38.65 %
suppression respectively) but when used as a
mixture they recorded better results (70.66
% suppression).
Three days after spraying,
Fenazaquin was found most effective
(86.35% suppression) very closely followed
by avermectin (85.39% suppression) against
mite. There is no significant difference
between these two treatments but they are
significantly different from all other
treatments. Among the botanical insecticides
and plant extracts, neem and Spilanthes
floral part extracts (5% concentration)
individually are moderately effective against
mite providing 48.15% and 44.93%
suppression respectively but combination of
neem with Spilanthes (5% concentration)
gave better results recording 73.42 %
suppression of mite population. Six days
after spraying, Fenazaquin was found to be
the superior pesticide (79.97% suppression)
against mite and significantly different from
all other treatments. Among the bio-
pesticides, avermectin (72.62% suppression)
provided better results closely followed by
botanicals, mixture of neem and Spilanthes
(70.10% suppression). Six days after
spraying in case of neem and Spilanthes
extracts the results followed the findings of
three days after spraying. Nine days after
spraying Fenazaquin, avermectin and mixed
formlation of neem and Spilanthes were
found very active against mite pest (71.41%,
71.19% and 68.47% suppression
respectively) and there were no significant
difference in efficacy among these three
treatments.
Yield is directly related to the
efficacy of insecticides. Better yield was
obtained from plots treated with mixture of
neem and Spilanthes treatment (34.58 q/ha)
closely followed by avermectin (32.45 q/ha),
sulphur (31.55 q/ha) and fenazaquin (31.23
q/ha). There was no significant difference in
yield among these treatments. From overall
observations it was revealed that mixture of
neem and Spilanthes as well as microbial
toxin avermectin gave higher mite
suppression (more than 70% suppression)
and higher fruit yield. Considering the
moderate to higher efficacy as well as its
low toxicity to natural enemies and
minimum impact on human health, coupled
with higher yield potentially botanical and
microbial insecticides can be incorporated in
future IPM programme and organic farming
in vegetable cultivation.
CONCLUSION
Mite incidence showed non-
significant positive correlation with
temperature (maximum, minimum and

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average), maximum relative humidity and
total rainfall where as significant positive
correlation with minimum and average
relative humidity. The incidence of mite
population was higher on the upper canopy
of the plant i.e., mites were most densely
populated in the young and new leaves of
okra plant. So to suppress the population
upper canopy should be treated properly.
Peak population was recorded during
May in the pre-kharif crop and during
October in the post kharif crop. During these
periods of the year drastic control measure
should be adopted in the sub-Himalayan
region of North-East India. Bio-pesticides
like microbial toxin avermectin and
combination of neem with Spilanthes floral
part extracts gave better results. Neem and
Spilanthes individually did not produce
good results but when used as a mixture they
recorded better results. Based on their
moderate to high efficacy levels, as well as
low toxicity to natural enemies and
minimum impact on human health, and
higher yield potentiality, we conclude that
bio-pesticides can be incorporated in future
IPM programme and organic farming in
vegetable cultivation.
ACKNOWLEDGEMENTS
I thank the support rendered by the
Department of Agricultural Entomology,
UBKV by providing laboratory and field to
carry out the study. Also thanks are due to
all those who have contributed to it.

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Table 1: Correlation co-efficients between mite (T. urticae) and weather parameters
Environmental parameter Correlation co-efficient (r)
Temperature
0
C Maximum 0.226
Minimum 0.226
Difference (-)0.147
Average 0.263
Relative Humidity
(%) Maximum 0.228
Minimum 0.384*
Average 0.355*
Rainfall (mm) Total 0.057
*Significant at 5% level of significance
Table 2: Efficacy of pesticides against red spider mite (T. urticae) and the yield of okra
Treatments
Dose
ml or
g/L(%)
Pretreatment
observation
(mites/Leaf)
Overall efficacy ( % reduction)
Days after treatment
Fruit
yield
(q/h)
3
6
9
Mean
T
1
=Avermectin (Vertimec 1.9
EC)
1 ml/L
3.89
85.39
(67.62)
72.62
(58.52)
71.19
(57.54)
76.40
(61.23)
32.45
T
2
=Neem (Nemactin 0.15 EC)
2.5 ml/L
4.33
48.15
(43.94)
45.94
(42.65)
37.08
(37.51)
43.72
(41.37)
27.44
T
3
=
Spilanthes
flower extract
(1%)
10 ml/L
4.21
33.93
(35.61)
34.56
(36.01)
27.33
(31.52)
31.94
(34.38)
23.47
T
4
=
Spilanthes
flower extract
(5%)
50 ml/L
3.89
44.93
(35.61)
34.56
(36.01)
36.47
(37.13)
38.65
(36.25)
26.11
T
5
=
Neem+
Spilanthes
ext
ract
(5%)
2.5
ml/L+ 50
ml/L
4.56
73.42
(57.95)
70.10
(56.79)
68.47
(55.89)
70.66
(56.88)
34.58
T
6
= Sulphur (Sulfex 80 WP)
5 g/L
3.78
80.16
(63.38)
59.01
(51.49)
64.59
(53.50)
67.92
(56.12)
31.55
T
7
= Fenazaquin(Magister 10EC)
2ml/L
4.33
86.35
(68.40)
79.9
7
(64.36)
71.41
(57.37)
79.24
(63.38)
31.23
T
8
=Untreated check(control)
-
4.21
0.00
(4.05)
0.00
(4.05)
0.00
(4.05)
0.00
(4.05)
21.72
SEm(±)
-
-
1.94
2.41
2.03
-
1.71
CD(p=0.05)
-
NS
5.77
7.18
6.03
-
5.08
Figures in parentheses are angular transformed values, NS = Not significant

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REFERENCES
Abott, W.S. 1925. A method of computing
the effectiveness of an insecticide. J.
Econ. Ent. 18: 265-267.
Acharya, S., Mishra, H.P. and Dash, D.
2002. Efficacy of insecticides against
okra jassid (Amrasca biguttula
biguttula Ishida). Annals of Plant
prot. Sci. 10 (2): 230-232.
Anitha, K.R. and Nandihalli, B.S. 2008.
Seasonal incidence of sucking pests
in okra ecosystem. Karnataka J.
Agric. Sci. 21 (1): 137-138.
Anonymous, 2005. The Hindu Surv. Indian
Agric., Chennai, pp 51-56.
Dobson, H., Copper, J., Manyangarirwa, W.,
Karuma, J. and Chiimba, W. 2002.
Integrated vegetable pest
management: Safe and sustainable
protection of small-scale brassicas
and tomatoes-A hand book for
extension staff and trainers in
Zimbabwe. Published by NRI,
University of Greenwich, UK.P.179.
Donatoni, J.L., Bindo,C.J., Clari, A.L. and
Mariconi, F.A.M. 1988. Chemical
acaricides for the control of the
broad mite. P. latus on cotton crop.
Analis da Sociedate Entomologica de
Brasis. 17 (2): 283-92.
Dutta, N.K., Alam, S.N., Uddin, M. K.,
Mahumudunnabi, M. and Khatun,
M.F. 2011. Incidence and spatial
distribution of red spider mite,
Tetranychus Urticae in brinjal and
its chemical control. Bangladesh J.
Entomol. 21(1):45-52.
Fitzgerald, J., Xu, X., Pepper, N.,
Easterbrook, M. and Solomon, M.
2008. The spatial and temporal
distribution of predatory and
phytophagous mites in field-grown
strawberry in the UK. Exp. Appl.
Acarol. 44(4):293-306.
Ghosh, J., Ghosh, S.K., Chatterjee, H. and
Senapati, S.K. 1999. Pest constraints
of okra under terai region of West
Bengal. Indian Journal of
Entomology. 61 (1): 362-71.
Gupta, S.K. 1985. Hand Book of plant
mites in India. Zoological Survey of
India. Calcatta, 520.
Heungens, A. and Degheele, D. 1986.
Control of the broad mite
Polyphagotarsonemus latus (Bank.)
with acaricide on Psophocarpus
tetragonalobus and Ricinus
communis. Parasitica. 42 (1): 3-10.
Jeppson, L.R., Keifer, H.H. and Baker,
E.W. 1975. Mite injurious to
economic plants. University of
California Press, Berkeley,
California. Pp 614.
Krishnakumar, N.K. and Srinivasan, K.
1987. Efficacy and economics of
pest control in okra with
conventional and synthetic

Current Biotica 7(1&2): 40-50, 2013 ISSN 0973-4031
_____________________________________________________________________________________
www.currentbiotica.com 50
pyrethriod insecticides. Indian J.
Plant Prot. 15: 81-83.
Kumar, V., Chandraskekar, K. and Sidhu,
O.P. 2007. Synergistic action of
neem and karanj to aphid and mite.
Journal of Entomological research.
31 (2): 86 (Users online).
Muraleedharan, N. 1993. Avermectin, a
new group of pesticides. The
Planters Crinicle. Pp. 315-316.
Pillai, K.S. and Palanoswami, M.S. 1983.
Economics on the control of spider
mites on cassava. Entomon, 8: 373-
375.
Puttaswami, M. and Channabasavanna, G.P.
1980. Influence of host plantson the
development, fecundity and
longevityof Tetranychus ludeni
Zacher (Acari: Tetranychidae).
Indian J. Acarol. 5: 80-84.
Sarkar, A and Mukherjee, P.K. 2005.
Ecology of Polygonum: a
predominant weed in terai agro
climatic region of West Bengal. Ann.
Agric. Res. 26 (3): 462-463.
Singh, R.N., Mukherji, I.N., Singh, R.K, and
Singh, J. 1987. Evaluation of some
pesticides against red spider mite
Tetranichus ludeni Zacher on
Cowpea. In. Proceeding 2. First Asia
Pacific conference of Entomology,
Thailand. 556-559.
Ziu H., Cheng, H.K. and Zhao, J.H. 1992.
Use of Liuyangmycin to control yellow
mite. P. latus infesting green pepper.
Chinese J. Biol. Cont. 8 (1): 29-32.
[MS received 05 September 2013;
MS accepted 29 September 2013]
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