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Efficacy of plant-soil exposure to electric current against Agrotis ipsilon, Bemisia tabaci and Meloidogyne sp

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EurAsian Journal of BioSciences
Eurasia J Biosci 14, 4439-4444 (2020)
Efficacy of plant-soil exposure to electric current against
Agrotis ipsilon, Bemisia tabaci and Meloidogyne sp
Asmaa Mansour Al-Hakeem 1*, Mohammed Yousuf S.Ghani 2, Nabil Mustafa AlMallah 2
1 AL-Karkh University of Science, College of Science, Department of Microbiology, IRAQ
2 University of Mosul, College of Agriculture and Forestry, Department of Plant Protection, IRAQ
*Corresponding author: asmaa.mansoor@kus.edu.iq
Abstract
A series of experiments were conducted during the years 2014 and 2016 to evaluate the effect of
exposing plant soil to electric current for different periods 2 and 5 min on the black cutworm larvae
on tomato, 4 and 8 min on whitefly nymphs on cucumbers and for 5, 10 and 15 min against the
second stage juvenile J2 of root-knot nematodes Meloidogyne spp. on olive trees. Normal electric
current 220V was used directly after irrigation with or without nitrogen fertilization in the case of
tomato and cucumber. The results showed that the electric current regardless of the exposure period
was highly effective and led to a significant (𝑃 ≤ 0.05) increase in mortality of black cutworm larvae
of tomato and white-fly nymphs. The highest numbers of dead larvae were in the fertilization
treatment and exposure period of 5 min. No live larvae were recorded in this treatment, which did not
differ from the 2 min exposure, but did significantly differ from the control (not exposed to electric
current). As for whitefly on cucumber, the highest mean of dead nymphs (48,00 nymphs/leaf) and the
lowest number of live ones (13,66) were in the fertilization treatment and 8min exposure to electric
current, which differed significantly (𝑃 ≤ 0.05) from all the other treatments. The same treatment
resulted in the highest value of dry shoot weight and total leaf area of the cucumber plant compared
to other treatments. The results of the laboratory experiment showed that incubation of RKN eggs
and J2s in electrified water led to stopping egg hatching and to the death of most J2s for all periods
of exposure (5, 10 or 15 min) compared to the high rate of hatching and vitality of most J2s in
untreated water. Similarly, the treatment of olive trees with electric current resulted in a significant
decrease (P≤0.05) in some RKN live males and J2s/100 g soil and a significant increase in the
number of dead individuals. Whereas, the highest numbers of active RKN J2s and males and lowest
numbers of dead individuals were recorded in the control treatment where the soil of the olive tree
was not treated with electrical current.
Keywords: Electrical Shock, black cutworm, whitefly, RKN
Al-Hakeem AM, S.Ghani MY, AlMallah NM (2020) Efficacy of plant-soil exposure to electric current
against Agrotis ipsilon, Bemisia tabaci and Meloidogyne sp. Eurasia J Biosci 14: 4439-4444.
© 2020 Al-Hakeem et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution License.
INTRODUCTION
Among the globally spreading insect pests, Agrotis
ipsilon (Hufn.) its one of the most important worms
spread in the Nineveh Governorate (Al-Jalal, 2005).
Bemisia tabaci is other pests of widespread economic
importance (McKenzie et al., 2009). The two insects are
characterized by a multiplicity of their food hosts and
great harm to.
crops due to the high food binge (Capinera, 2008).
The damage of the black cutworm is serious, especially
at later ages, unable to climb, which disappears during
the day and goes out for feeding at night, cutting the
stem of the plant in the area near the surface of the soil
(Binning et al., 2015). As for the white-fly insect, its
damage comes primarily from its transmission of viral
diseases (David, 2014) during its continuous feeding by
absorbing the succulents of the host plant even during
mating and laying eggs. Studies indicate that the white
fly transmits at least nine important viral diseases in the
Arab region (Al-Mallah and Nabeel, 2018).
The plant nematode is also an important settlement
in the soil that attacks the roots of plants and causes
economic losses on various crops all over the world
(Agrios, 2005). Olive trees are affected by plant
nematodes, especially the root-worms Meloidogyne,
which has been found to cause high losses in affected
trees in Iraq (Ismail et al., 2019).
For environmental and health reasons related to the
use of pesticides in general (Nayana and Ritu, 2017).
physical control methods, including electrocution, may
provide a suitable alternative to the possibility of their
inclusion in the integrated control program. In addition to
Received: Augut 2019
Accepted: April 2020
Printed: October 2020
EurAsian Journal of BioSciences 14: 4439-4444 (2020) Al-Hakeem et al.
4440
being able to be used as an alternative to chemical
pesticides, physical methods are characterized by their
limited or little impact on the environment and insects
inability to form resistant strains. as is the case with
pesticides (Weintraub and Berlinger, 2004).
The effect of the electric current has been studied in
various fields of plant sciences where it was found that
electro-shock can be used to stimulate plant growth,
increase productivity and improve its quality (Leo, 2013)
as well as in protecting plants from insects and diseases
(Niamouris and Psirofonia, 2014). This is done by
treating seeds, plants, soil, water, and nutrient solutions
with the electric field (Al-Kargooli and Alwan, 2016).
Although electrical current applications were introduced
in the field of pest management, they were often limited
to protecting plants from attacking insects inside
greenhouses (Matsuda et al, 2011) especially to prevent
the entry of whitefly (Takikawa et al, 2015), mosquito
control or wood treatment against termite infestation.
(Lewis and Haverly, 2001; Ebeling, 1983).
Electrocution against the plant nematode was used
for the first time (Daulton and Stokes, 1952) to kill root-
knot nematodes in water. An electric current of 200-
700Hz was used. The current- voltage, exposure time,
or temperature was not mentioned during the
experiment. In another study by Lear and Jacob, (1955),
it was found that all attempts were unsuccessful in killing
J2s and eggs of roots knot nematode Meloidogyne
incognita acrita.
Stockes and Martin (1954) also mentioned that
electrocution does not affect Meloidogyne javanica
nematodes when exposing a small amount of soil
containing nematodes to electrical current. In 1970
Fields and Caveness showed that electrocution of 5v /
mm for larvae and 10v / mm for adults resulted in the
death of larvae and adults of Panagrellus redivivus,
juvenile stages of the Meloidogyne incognita acrita,
while a voltage of 20-60 vdc / mm for 2 seconds
stimulated Meloidogyne eggs hatching.
Therefore, the current study, which is the first of its
kind in the Arab region, aims to evaluate the possibility
of using different methods of electric stun and for
different exposures in the control of cutworms on
tomato, white fly on cucumbers and roots knot
nematodes on olive trees in field conditions.
MATERIALS AND METHODS
All experiments were carried out during the years
2014 at the College of Agriculture and Forestry,
University of Mosul and 2016 at the College of
Agriculture, University of Diyala. The study included
laboratory and field tests to evaluate the use of electrical
current in controlling three different pests.
The effect of electric current on black cutworm
Agrotis ipsilon on tomato:
A field infested with Agrotis ipsilon was used where
tomato seedlings were planted in lines with drip irrigation
system in 1/3/2016. A metal wire was buried at a depth
of 5 cm below and along the drip tube. After 25 days of
planting and confirming the occurrence of plants
infection, random plants from affected lines were chosen
for electrocution treatments for 2 or 5 minute exposure
period with 3 replications per treatment. Electrocution
was done immediately after watering after adding
nitrogen fertilizer, or not adding fertilizer while plants not
exposed to electrical current served as control
treatment. The results were taken after 24 hours of
treatment for 5 infected random plants from each
repeater and the number of live and dead larvae was
calculated.
The effect of electrocution in Bemesia tabaci on
cucumber plants:
Cucumber seeds were planted on 1/3/2016 in the
same way with tomato plants. After the plants reached
the branching stage (height 15-20 cm) and making sure
that the pest of the white fly insect was present on the
leaves, the electrocution was carried out in the same
previous method, but the exposure periods 4 and 8
minutes for each treatment. Data were taken on the
basis of the effect of preparing nymphs on five infected
plants for each line (repeated) and five infected leaves
from each plant after 24 hours of treatment. Samples
were brought in polyethylene bags to the laboratory. The
number of living and dead nymphs was calculated by
direct examination of the leaf using the dissection
microscope.
At the end of the season, before harvesting, five
random option plants were sampled for each treatment
from each experimental unit to calculate the dry weight
and leafy area of the plant (Al-Habar et al. 2013; Al-
Sahhaf et al. 2011).
The effect of electrocution in controlling root-knot
nematodes on olive trees:
The laboratory part included testing the effect of
electrocution on egg hatching and the vitality of second-
stage juveniles (J2s) of Meloidogyne spp.
Samples were collected from the roots of the olive
trees infected with root complications, they were washed
thoroughly with running water and eggs were collected
under the dissection microscope. The egg suspension
was prepared from collecting egg masses in 50 ml
beaker containing sodium hypochlorite 0.5%
concentration with constant stirring for 3 minutes after
pouring the suspension in a 20 micron sieve, wash with
a slight stream of water for two minutes then collect in
50 ml beaker using distilled water (Stetine et al. 1997).
A quantity of egg sprouts was taken to incubate the
newly hatched juvenile suspension after placing it in the
incubator at a temperature of 30 ± 2 ° C (Bird and
Wallace, 1965). After completing the hatching, the
suspension was prepared to contain 35 ± 5.
EurAsian Journal of BioSciences 14: 4439-4444 (2020) Al-Hakeem et al.
4441
RESULTS AND DISCUSSION
The results showed that exposing tomato plants to
electric current for different periods led to a variation in
the numbers of dead and live larvae of the black
cutworm, according to the different fertilization factors
and periods of electric shock exposure (Table 1). The
highest number of dead larvae was recorded in the
presence of nitrogen fertilizer and a 5-minute exposure
period, which was 6.33 larvae, with a significant
difference from the number of dead larvae 3.66 larvae in
the absence of fertilization and for the same period of
exposure to electric current. Whereas, the lowest
number of dead larvae was (1,667 larvae) recorded in
non-fertilized plants after 2 min exposure period.
Generally, the number of live larvae was significantly
higher in the control treatment, which was not exposed
to electric current regardless of fertilization.
Similarly, the results of the exposure test of
cucumber plants against the whitefly insect (Table 2).
Fertilization resulted in an increase in the effect of the
electric current on the number of dead nymphs, which
differed significantly in the presence of fertilization and
the exposure period 4 minutes, compared with no
fertilization and in the same exposure period. Generally,
the highest rates of the number of dead nymphs were
recorded in plants exposed to electrical current for 8
minutes in the presence of nitrogen fertilizer with a
significant difference from that of non-fertilizing.
The same treatment resulted in reducing the number
of live nymphs to 13.6 compared to 97.6 nymphs on
leaves of plants not exposed to electric current (Table
2). The mortality of the black cutworm larvae on tomato
and white fly nymphs on cucumber plants is mostly due
to the direct effect of electric current which leads to
dryness of insect bodies and death as results of stopping
feeding. These findings were similar to the results of
previous studies were using the electric current was
effective in controlling insect pests on different crops
(Niamouris and Psirofonia, 2014; Takikawa et al., 2015).
The nitrogen fertilization on the other hand, increased
the effectiveness of electric current against different
stages of insects. This is undoubtedly due to the
properties of these fertilizers, which are known to
increase the electrical conductivity of EC for the soils
added to (Naseem et al., 2019) especially when
maintaining high humidity resulting in higher electrical
conductivity and consequently much higher effect on the
effect on insect pests.
The results (Table 2) also indicate that the treatment
with electric current, regardless of the presence of
fertilizer, indicates a significant increase in the average
leafy area and dry weight of the cucumber plant
compared to the treatment exposed to the electric
current. Whereas, the highest increase in leaf area and
shoot DW were recorded in the combined treatment of
nitrogen fertilization and 8min exposure to electrical
current. The results of the study agreed with Hussein
(2009), which indicated the possibility of increasing the
leafy area of chrysanthemum plants by introducing them
to electric current. This is consistent with previous
studies where exposing plants to electrical current for
certain times and periods leading to improved growth
characteristics (Leo, 2013; Al-Kargooli and Alwan,
2016).
The results of the laboratory experiment indicated
that the exposure of water to electric current had an
effect on egg hatching and the vitality of young worms of
complexity (Table 3). The highest number of live J2s
was recorded in the control treatment of non-electrified
water regardless of the incubation period. Whereas, the
lowest number of active J2s, ranging from 0 to 2, was
recorded in dishes containing electrified water. The
duration of the current exposure did not differ among
each other in the number of active J2s. The reason for
the death of the juveniles is due to their presence in the
aqueous medium, which is highly conductive to the
Table 1. Effect of electric current exposure period and fertilization on number of black cutworm larvae on tomato 24 hours
post treatment
Mortality of Black cutworm
Electricity exposing period (min)
No. of dead larvae
No. of live larvae
0
0.0 d
8.33 a
2
4.00 ab
0.66 b
5
6.33 a
0.00 b
0
0.0 d
9.00 a
2
1.66 cd
1.00 b
5
3.66 bc
0.33 b
Table 2. Effect of electric current exposure period and fertilization on number of white fly nymphs on cucumber and some
growth parameters
Whitefly viability
Plant growth parameters
Treatment
Electricity exposing
period (min)
No. of dead nymph
No. of live nymph
Leaf area
Cm2
Shoot dry weight
g/plant
Fertilized
0
0.00 d
97.6 a
832 d
64.33 c
4
31.33 b
32.0 c
1224.0 b
91.66 a
8
48.0 a
13.6 d
1277.0 a
94.66 a
Unfertilized
0
0.00 d
92.3 a
861.3 d
67.33 c
4
16.3 c
41.66 b
1177.0 c
83.00 b
8
31.0 b
27.66 c
1202 b
90.00 a
EurAsian Journal of BioSciences 14: 4439-4444 (2020) Al-Hakeem et al.
4442
electric current. This electrical environment affected the
vital activities of the nematode, leading to paralyzing
their movement and thus death.
The effects of exposure to the electric current on the
number of hatching eggs of root nematode complexes
(Table 3). The results showed that all periods of
exposure 5, 10 and 15 minutes of electric current did not
differ between them and often resulted in a complete
cessation of hatching. Whereas, the control treatment
for the eggs of complex worms in non-electrified water
had a high hatching rate with an increase in the
incubation period, especially on the fourth day (25.6)
and the sixth day is (43) and with a significant difference
from the rest of the treatments. It appears from the
results that the increased exposure period led to the
killing of larvae inside the eggs or contributed to stopping
their vital activities towards hatching (Fields and
Caveness, 1970) In case of the field experiment, the
results also showed that electric current affected the
viability of RKN J2s and males associated with the roots
of olive trees (Table 3). The highest number of J2s and
males (130/100gm soil) was recorded in the soil of olive
trees not treated by electrical current (control). While
exposing the trees to the electric current for a period of
5 and 10 minutes resulted in a significant decrease in
the number of juveniles and live males/100g soil which
was 49 and 42.6 respectively. The 15 minutes exposure
to electric current significantly resulted in the lowest
number (27.6 J2 and male/100g soil) and the highest
number of dead J2 and male (81.6).
The low efficacy of the electric current against J2s of
RKN in previous studies (Stockes and Martin, 1954) may
often be attributed to the field conditions upon treatment
(Naseem et al., 2019). In this study, the irrigation of the
orchard was by the drip method, which provided a high
moisture level and consequently a high-intensity
electrical conduction, which led to the killing of large
numbers of juveniles and males in the soil.
Exposing plants to electrical current in an accurate
and thoughtful way generally helps to improve plant
growth and productivity. Also, reducing plant parasitic
nematodes population that associated with plants roots
will inevitably reduce the severity of infection and
improve plant health (Timper et al, 2006; Ewaid; et.al
2019).
CONCLUSION
This study showed the efficiency of using electric
current against insect pests black cutworm Agrotis
ipsilon in Lepidoptera, whitefly Bemisia tabaci in
Hemiptera and Root-knot nematodes Meloidogyne spp.
which are among the important non-insect animal pests
that attack the roots of many plants of economic
importance. The results showed that the effect of electric
current against pests under study increased in the
presence of nitrogen fertilizer and high moisture content.
Using an electric current as soil application in the
rhizosphare zone of the plant did not affect plant vitality,
but rather increased the growth indicators in the treated
plants. The method used in our study is a very promising
method in the field of using electric current to control
pests and exceeded that negative impact on the plant in
previous studies as for examples:
1-In a preliminary study of the effect of electric
current in controlling the various stages of the red palm
weevil Rhynchophorus ferrugineus, Niamouris &
Psirofonia (2014) was mentioned this is the first time
electric current is tested in date palms as a method to
control an insect. But at the same time it pointed out
several negative aspects or problems that must be
solved in the future, including:
a-The death of half of the treated palm trees by
electrocution due to adding water to the trees.
b-The very weak effect of the electrocution on insect
adults compared to other incomplete stages, which are
due to a cutical insect adult.
c-The necessity of conducting other studies using the
forces and frequencies of the electrical current to
determine the most appropriate ones, as well as the
method itself, i.e. tree perforation and the method used
2- Four patented methods of controlling insects with
electricity
a. US3826035
b. ΚR20100138535
c. JP2004141127
d. JPS53127173 .
All of the above have major differences with the
method described earlier in the paper and to our
knowledge have not yielded any fruitful results.
ACKNOWLEDGEMENT
Wed like to express our thanks and appreciations to
the Department of Plant Protection/ Faculty of
Table 3. Effect of exposure period to electric current on RKN in vitro J2s viability and eggs hatchability and in vivo number
of active J2s and males in soil of olive trees roots
Exposure period to electric current (min)
Laboratory experiment
Field experiment (Olive orchard)
No. of active J2/35±5
No. of hatched eggs/50±7
No. of J2 and males/100g soil
30 min
60 min
24 h
Day 1
Day 2
Day 4
Day6
Live
Dead
0
30 a
30 a
28 a
0
3 c
25.6b
43 a
130 a
1.3 d
5
2b
0 b
0 b
0
0 c
2 c
1 c
49 d
56.3 c
10
0 b
0 b
0 b
0
0 c
0 c
0 c
42.6 d
70 b
15
0 b
0 b
0 b
0
0 c
0 c
0 c
27.6 e
81.6 a
EurAsian Journal of BioSciences 14: 4439-4444 (2020) Al-Hakeem et al.
4443
Agriculture and Forestry/University of Mosul and to the
Microbiology Department /college of Science/AL-Karkh University of Science for the support and cooperation in
completing this work.
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