Evaluation of some pesticides against the tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under laboratory conditions

Abstract

The tomato borer, Tuta absoluta (Meyrick) is considered a devastating pest, particularly to the tomato Lycopersicon esculentum. The present study was carried out to determine the efficacy of five pesticides namely, indoxacarb, (abamectin+ thiamethoxam), emamectin benzoate, fipronil and imidacloprid against the 3 rd larval instar of T. absoluta under laboratory conditions using the Leaf-dip method. The tested pesticides could be descendingly arranged as follows: emamectin benzoate, fipronil, (abamectin + thiamethoxam), indoxacarb and imidacloprid. The corresponding LC 50 values after 72 h. were 0.07, 0.22, 0.28, 0.59 and 2.67 ppm, while LC 90 values were 0.56, 3.25, 1.99, 4.69 and 30.29 ppm, respectively. It is clear that emamectin benzoate was the most toxic compound, whereas imidacloprid was the least toxic one. Results indicated that emamectin benzoate can be used as a good element in integrated management program to this pest.

Full text

SVU-International Journal of Agricultural Science
Volume 2 Issue (1) pp.:13-21. 2020
Print ISSN 2636-381X | Online ISSN 2636-3801
RESEARCH ARTICLE
13
Evaluation of some pesticides against the tomato borer, Tuta absoluta (Meyrick)
(Lepidoptera: Gelechiidae) under laboratory conditions
Mohanny K.M., G.S. Mohamed, R.O.H. Allam, and R.A. Ahmed*
Plant Protection Department, Faculty of Agriculture, South Valley University, Qena 83523, Egypt
Abstract: The tomato borer, Tuta absoluta (Meyrick) is considered a devastating pest, particularly
to the tomato Lycopersicon esculentum. The present study was carried out to determine the
efficacy of five pesticides namely, indoxacarb, (abamectin+ thiamethoxam), emamectin benzoate,
fipronil and imidacloprid against the 3rd larval instar of T. absoluta under laboratory conditions
using the Leaf-dip method. The tested pesticides could be descendingly arranged as follows:
emamectin benzoate, fipronil, (abamectin + thiamethoxam), indoxacarb and imidacloprid. The
corresponding LC50 values after 72 h. were 0.07, 0.22, 0.28, 0.59 and 2.67 ppm, while LC90 values
were 0.56, 3.25, 1.99, 4.69 and 30.29 ppm, respectively. It is clear that emamectin benzoate was
the most toxic compound, whereas imidacloprid was the least toxic one. Results indicated that
emamectin benzoate can be used as a good element in integrated management program to this
pest.
Key words: Abamectin, Fipronil, Emamectin benzoate, Indoxacarb, Tomato, Tuta absoluta
1. Introduction
The tomato borer, Tuta absoluta (Meyrick) is
a Lepidopteran species of the family
Gelechiidae it has assumed the status of the
most important pest in Egypt. It has been
reported in Egypt since 2009, quickly
becoming one of the major pests of the
tomato crop. T. absoluta is a multivoltine
species that mines leaves, fruits, flowers,
buds and stems. The damage is produced
when the larvae feed on the leaf mesophyll
expanding mines, thus affecting the
photosynthetic capacity of the crop with
subsequent reduction of yield. Moreover,
injury made directly to the fruits causes
severe losses (Colomo and Berta, 2006).
*Corresponding author: R.A. Ahmed
Email: raniaatefahmed75@gmail.com
Received: December 17, 2019;
Accepted: January 2, 2020;
Published: January 6, 2020.
Larvae do not enter diapause when food is
available and depending on the
environmental conditions, so up to 12
generations per year may be able to develop
(EPPO, 2005). Even though T. absoluta is an
oligophagous pest with a strong preference
for tomato (Notz, 1992) it can also attack
other cultivated Solanaceae plants such as
eggplant (Solanum melongena L.), potato
(Solanum tuberosum), pepper (Capsicum
annuum), sweet pepper (Solanum muricatum
L.), tobacco (Nicotiana tabacum). Also, it
infests Phaseolus vulgaris L. (bean) and
Physalis peruviana L. (Cape gooseberry)
(Desneux et al., 2010). Chemical Pesticides
are one of the most common and widely used
methods for controlling T. absoluta around
the world because they have rapid action and
strong toxicity against the target pest. Many
researches has been done on using chemical
pesticides for controlling T. absoluta

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
14
(Braham et al., 2012b.; Hafsi et al., 2012.;
Deleva and Harizanova, 2014) with a great
diversity of pesticide classes commonly used,
such as carbamates, neonicotinoids,
pyrethroids, avermectins, spinosyns, diamide
and insect growth regulators (MAPA, 2017).
The aim of this work was to evaluate
different pestiticides against T. absoluta
under laboratory conditions and to determine
the effective dose for field application to
succeed in controlling this pest under Upper
Egypt conditions.
2. Materials and Methods
2.1. Vegetable crop investigated
Tomato plants Lycopersicon esculentum Mill
Varity Super strain B Hybrid was cultivated
in the farm of Faculty of Agriculture at South
Valley University during (2017-2018)
season.
2.2. Insects
Tuta absoluta larvae were collected from
infested tomato plants from the farm of
Faculty of Agriculture at South Valley
University.
2.3. Bioassey experiment
Laboratory experiment was carried out to
determine the effect of different pesticides
under laboratory conditions using the Leaf-
dip method. Five pesticides: indoxacarb,
(abamectin + thiamethoxam), emamectin
benzoate, fipronil and imidacloprid. Five
concentrations of each tested pesticides were
prepared. Fresh tomato leaflets were dipped
in each prepared concentration of the tested
pesticides for 10 seconds, control leaflets
were dipped in water only (three replicates
were used for each concentration), then the
leaflets were left to dry. The dried leaflets
were placed on a slightly moistened filter
paper covering the bottom of petri dishes (8
cm diameter × 1.5 cm height). Ten 3rd instar
larvae of T. absoluta were carefully placed
using a fine soft brush in each petri dishes
and kept under laboratory conditions (IRAC,
2010). Mortality was counted after 24, 48
and 72 hours. Larvae were considered as
dead when they were not able to move back
to the ventral position after being placed on
their dorsum.
Table 1. Pesticides used in the study
No
Common name
Trade name
Type of
Formulation
Conc.%
Rate/Fd
Chemical group
1
Abamectin +
Thiamethoxam
Gate Fast
SC
12
200 ml
Avermectin +
Neonicotinoid
2
Fipronil
Coach
SC

50 ml
Pyrazole
3
Imidacloprid
Avenue
WG

 gm
Neonicotinoid
4
Emamectin benzoate
Minoclem
WG

60

gm
Avermectin
5
Indoxacarb
Flax
SC

50 ml
Oxadiazine
2.4. Statistical analysis
Data were considered acceptable if the
mortalities observed in controls were less

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
15
than 20%. If there were mortalities in
controls, data were adjusted using Abbot's
formula (1925). Concentration-mortality
regression lines were analyzed using a
computer program modified from the method
of Finney (1971) to estimate the LC50, the
confidence limits and the slopes of LdP lines.
3. Results
3.1. Toxicity of the tested pesticides against
the 3rd instar larvae of the tomato borer, T.
absoluta under laboratory conditions
Data in Table (2) and Fig. (1) represented the
relative toxicity of the toxic action of
indoxacarb, (abamectin + thiamethoxam),
emamectin benzoate, fipronil and
imidacloprid against 3rd instars larvae of T.
absoluta by leaf dipping method at 24 h. post
treatment. Data clearly indicate that the
tested pesticides could be descendingly
arranged as follows: emamectin benzoate,
fipronil, (abamectin + thiamethoxam),
indoxacarb and imidacloprid. The
corresponding LC50 values were 0.13, 0.36,
0.59, 0.94 and 3.93 ppm, while the LC90
values were 2.75, 5.85, 3.36, 6.38 and 40.82
ppm. On the other hand, χ2 values were 0.04,
0.18, 0.87, 0.26 and 0.53 respectively. Data
in Table (2) show Toxicity of tested
pesticides against the 3rd instar larvae of T.
absoluta after 24 hours it was observed that
the toxicity index of emamectin benzoate,
fipronil, (abamectin + thiamethoxam),
indoxacarb and imidacloprid were 100,
36.11, 22.03, 13.82, and 3.31 % at the LC50
level, respectively.
Table 2. Toxicity of tested pesticides against the 3rd instar larvae of T. absoluta after 24 h.
Pesticides
χ2
LC50
ppm
confidence
limits of LC50
ppm
LC90
ppm
Slope ±SE
T.I.
Lower
Upper
Emamectin benzoate
0.04
0.13
0.03
0.22
2.75
0.96±0.29
100
Fipronil
0.18
0.36
0.21
0.65
5.85
1.05±0.32
36.11
Abamectin+Thiamethoxam
0.87
0.59
0.39
0.8
3.36
1.69±0.29
22.03
Indoxacarb
0.26
0.94
0.63
2.38
6.38
1.54±0.38
13.82
Imidacloprid
0.53
3.93
2.08
22.68
40.82
1.26±0.33
3.31
χ2 = Chi-square T. I. = Toxicity Index (compared with Emamectin benzoate)

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
16
Figure 1. Toxicity of tested pesticides against the 3rd instar larvae of T. absoluta after 24 h.
Data in Table (3) and Fig. (2) represented the
relative toxicity of the pesticides at 48 h.
after treatment. Data clearly indicate that the
tested pesticides could be descendingly
arranged as follows: emamectin benzoate,
fipronil, (abamectin + thiamethoxam),
indoxacarb and imidacloprid. The
corresponding LC50 values were 0.09, 0.30,
0.43, 0.74 and 3.62 ppm, while the LC90
values were 1.22, 5.13, 3.32, 6.60 and 38.6
ppm. On the other hand, χ2 values were 0.01,
0.38, 2.09, 0.17 and 0.95 respectively. The
toxicity index of emamectin benzoate,
fipronil, (abamectin + thiamethoxam),
indoxacarband imidacloprid were 100, 30,
20.93, 12.16 and 2.48 % at the LC50 level,
respectively. As shown in Table (3)
emamectin benzoate was the most toxic
compound against larvae of T. absoluta the
difference between the values of LC50 was
significant. Data in Table (4) and Fig. (3)
Represented the relative toxicity of the toxic
action of the pesticides at 72 h. after
treatment. Data clearly indicate that the
tested pesticides could be descendingly
arranged as follows: emamectin benzoate,
fipronil, (abamectin + thiamethoxam),
indoxacarb and imidacloprid.
The corresponding LC50 values were 0.07, 0.22,
0.28, 0.59 and 2.67 ppm, while the LC90 values
were 0.56, 3.25, 1.99, 4.69 and 30.29 ppm. On
the other hand, χ2 values were 0.13, 0.32, 0.27,
0.52 and 0.37 respectively. Data in Table (4)
show that the toxicity index of emamectin
benzoate, fipronil, (abamectin + thiamethoxam),
indoxacarb and imidacloprid were 100, 31.82,
25, 11.86 and 2.62 % at the LC50 level,
respectively. As shown in Table (4) emamectin
benzoate was the most toxic compound against
larvae of T. absoluta the difference between the
values of LC50 was significant.

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
17
Table 3. Toxicity of tested pesticides against the 3rd instar larvae of T. absoluta after 48 h.
Pesticides
χ2
LC50
ppm
confidence
limits of LC50
ppm
LC90
ppm
Slope ±SE
T.I.
Lower
Upper
Emamectin benzoate
0.01
0.09
0.02
0.16
1.21
1.13±0.32
100
Fipronil
0.38
0.30
0.16
0.51
5.13
1.04±0.32
30
Abamectin+Thiamethoxam
2.09
0.43
0.24
0.63
3.32
1.45±0.29
20.93
Indoxacarb
0.17
0.74
0.49
1.81
6.60
1.35±0.35
12.16
Imidacloprid
0.95
3.62
1.95
18.92
38.6
1.25±0.33
2.48
χ2 = Chi-square T. I. = Toxicity Index (compared with Emamectin benzoate)
Figure 2. Toxicity of tested pesticides against the 3rd instar larvae of T. absoluta after 48 h.

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
18
Table 4. Toxicity of tested pesticides against the 3rd instar larvae of T. absoluta after 72 h.
Pesticides
χ2
LC50
ppm
confidence
limits of LC50
ppm
LC90
ppm
Slope ±SE
T.I.
Lower
Upper
Emamectin benzoate
0.13
0.07
0.02
0.12
0.56
1.44±0.37
100
Fipronil
0.32
0.22
0.09
0.34
3.25
1.09±0.33
31.82
Abamectin+Thiamethoxam
1.27
0.28
0.13
0.43
1.99
1.51±0.32
25
Indoxacarb
0.52
0.59
0.42
1.13
4.69
1.43±0.35
11.86
Imidacloprid
0.37
2.67
1.54
10.08
30.29
1.21±0.31
2.62
χ2 = Chi-square T. I. = Toxicity Index (compared with Emamectin benzoate)
Figure 3. Toxicity of tested pesticides against the 3rd instar larvae of T. absoluta after 72 h.

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
19
4. Discussion
The effect of all five pesticides has increased
and reached the highest after 72 h. after the
bioassay. It is obvious, as shown in Tables
(2), (3), (4) and Fig. (1), (2), (3) that
emamectin benzoate had the steepest toxicity
line and imidacloprid had the flattest,
however fipronil, (abamectin +
thiamethoxam), indoxacarblie in between;
this reflects the superiority of emamectin
benzoate and inferiority of imidacloprid.
These results were in agreement with those
of Braham and Hajji (2012a) who showed
that emamectin benzoate confirmed its
effectiveness in populations of T. absoluta in
laboratory. Bala et al. (2019) found that the
highest susceptibility was observed from
abamectin with mortality of 86% and LD50 of
0.034 ppm. Roditakis et al. (2013) estimated
the toxicity of some insecticides registered
for T. absoluta control namely,
flubendiamide, chlorantraniliprole,
emamectin benzoate, spinosad,
metaflumizone, indoxacarb, chlorpyriphos
and cypermethrin. The results showed that
Low heterogeneity was detected in the
populations tested with most insecticides.
The LC50 values ranged from 0.31 to 1.31 mg
/ L for flubendiamide, from 0.12 to 0.53 mg /
L for chlorantraniliprole, from 0.03 to 0.12
mg / L for emamectin benzoate, from 0.08 to
0.26 mg / L for spinosad, from 31.8 to 159.5
mg / L for metaflumizone, from 1.73 to 17.5
mg / L for indoxacarb, from 530 to 2038 mg
/ L for chlorpyriphos and finally from 475 to
794 mg / L for cypermethrin. Shalaby et al.
(2012) showed that cyfluthrin, profenofos
chlorpyriphos-methyl lufenuron, and
indoxacarb were the most toxic insecticides
as compared to other chemicals against
tomato leaf miner, T. absoluta under the
laboratory conditions. Gacemi et al. (2016)
studied the effectiveness of two biopesticide,
emamectin benzoate and spinosad against
larval stages of T. absoluta under laboratory
conditions. Their results showed that the
emamectin benzoate and spinosad were very
effective on larvae of T.absoluta. The
emamectin benzoate caused complete
mortality of treated larvae. Gacemi and
Guenaoui (2012) conducted greenhouse
experiments to demonstrate the effect of
emamectin benzoate on T. absoluta; the
results showed very significant effect of
emamectin benzoate against larvae of this
pest. Abdel-Baky et al. (2019) evaluated the
efficacy of emamectin benzoate insecticide
against T. absoluta under laboratory
conditions its results indicated that
emamectin benzoate was effective against
larval stages of T. absoluta under laboratory
conditions and caused a significant
percentage mortality after 24 hours of
treatment and the percentage of mortality
increased gradually with time. Abdelgaleil et
al. (2015) determined the effectiveness of
four insecticides, abamectin + thiamethoxam,
chlorpyrifos, spinosad and imidacloprid in
controlling T. absoluta and he found that
imidacloprid was the least effective one.
5. Conclusion
The evaluation of tested pesticides showed
that emamectin benzoate was the most toxic
compound, whereas imidacloprid was the
least toxic one against Tuta absoluta
(Meyrick). Therefore, it was recommended
that emamectin benzoate can be used as an
element in integrated pest management of
Tuta absoluta (Meyrick) under Upper Egypt
conditions.
Acknowledgements
This study was kindly sponsored by the Plant
Protection Department, Faculty of

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
20
agriculture, South Valley University, Qena,
Egypt.
Conflict of interest
The authors hereby declare that no
competing and conflict of interests exist.
References
Abbott, W.S. (1925) 'A method of computing
the effectiveness of an insecticide', J.
econ. Entomol, 18(2), pp. 265-267. doi:
10.1093/jee/18.2.265a
Abdel-Baky, N.F., Alhewairini, S.S., Bakry,
M. (2019) 'Emamectin-benzoate against
Tuta absoluta Meyrick and Spodoptera
littoralis Boisduval larvae', Pakistan
Journal of Agricultural Sciences, 56(3),
pp.801-808. doi:
10.21162/PAKJAS/19.8082
Abdelgaleil, S. A., El-Bakary, A. S., Shawir,
M. S., Ramadan, G. R. (2015) 'Efficacy
of various insecticides against tomato
leaf miner, Tuta absoluta, in Egypt',
Applied Biological Research, 17(3), pp.
297-301. doi:10.5958/0974-
4517.2015.00042.7
Bala, I., Mukhtar, M., Saka, H., Abdullahi,
N., Ibrahim, S. (2019) 'Determination of
Insecticide Susceptibility of Field
Populations of Tomato Leaf Miner (Tuta
absoluta) in Northern Nigeria',
Agriculture, 9(7), pp.1-13. doi:
10.3390/agriculture9010007
Braham, M., Glida-Gnidez, H., Hajji, L.
(2012b) 'Management of the tomato
borer, Tuta absoluta in Tunisia with
novel insecticides and plant extracts',
EPPO bulletin, 42(2), pp. 291-296. doi:
10.1111/epp.2572
Braham, M., Hajji, L. (February 15th 2012a)
'Management of Tuta absoluta
(Lepidoptera, Gelechiidae) with
insecticides on tomatoes', in Farzana
Perveen (Ed.). Insecticides-Pest
Engineering. IntechOpen, pp. 333-354.
doi: 10.5772/27812
Colomo, M.V., Berta, D.C. (2006) 'First
record of a member of the Exoristini
(Diptera, Tachinidae) in Tuta absoluta
(Lepidoptera, Gelechiidae)', Acta
Zoologica Lilloanna, 50(1/2), pp. 123-
124.
Deleva, E.A., Harizanova, V.B. (2014)
'Efficacy evaluation of insecticides on
larvae of the tomato borer Tuta absoluta,
Meyrick (Lepidoptera: Gelechiidae)
under laboratory conditions', Agriculture
and Food, 2(1), pp. 158-164.
Desneux, N., Wajnberg, E., Wyckhuys, K.
A., Burgio, G., Arpaia, S., Narváez-
Vasquez, C.A., Pizzol, J. (2010)
'Biological invasion of European tomato
crops by Tuta absoluta: ecology,
geographic expansion and prospects for
biological control', Journal of pest
science, 83(3), pp. 197-215. doi:
10.1007/s10340-010-0321-6
EPPO. (2005) 'European and Mediterranean
Plant Protection Organization. Tuta
absoluta. Data sheets on quarantine
pests', EPPO Bulletin, 35, pp. 434-435.
doi: 10.1111/j.1365-2338.2005.00852.x
Finney, D. J. (1971) 'Probit analysis',
Cambridge University Press. Cambridge,
UK.
Gacemi, A., Bensaad, R., Guenaoui, Y.
(2016) 'Effect of Biopesticides Spinosad
and Emamectin on Developmental
Stages of the Tomato Leafminer Tuta
absoluta Meyrick (Lepidoptera:

Mohanny et al., : SVU-International Journal of Agricultural Sciences, 2 (1): 13-21, 2020
______________________________________________________________________________________
21
Gelechiidae)', Academic Journal of
Entomology, 9(1), pp. 08-13.
doi:10.5829/idosi.aje.2016.9.1.10253
Gacemi, A., Guenaoui, Y. (2012) 'Efficacy of
emamectin benzoate on Tuta absoluta
Meyrick (Lepidoptera: Gelechiidae)
infesting a protected tomato crop in
Algeria', Academic Journal of
Entomology, 5(1), pp. 37-40 doi:
10.5829/idosi.aje.2012.5.1.6315
Hafsi, A., Abbes, K., Chermiti, B., Nasraoui,
B. (2012) 'Response of the tomato miner
Tuta absoluta (Lepidoptera:
Gelechiidae) to thirteen insecticides in
semi‐natural conditions in Tunisia',
EPPO bulletin, 42(2), pp. 312-316. doi:
10.1111/epp.2575
IRAC. (2010) 'Insecticide Resistance Action
Committee', Susceptibility test methods
series.
MAPA. (2017) 'Ministério da Agricultura,
Pecuáriae Abastecimento. Brazil',
http://agrofit.agricultura.gov.br/agrofit_c
ons/principal_agrofit_cons (Accessed:
23 September).
Notz, A.P. (1992) 'Distribution of eggs and
larvae of Scrobipalpula absoluta in
potato plants', Revista de la Facultad de
Agronomía (Maracay), 18, pp. 425- 432.
Roditakis, E., Skarmoutsou, C., Staurakaki,
M. (2013) 'Toxicity of insecticides to
populations of tomato borer Tuta
absoluta (Meyrick) from Greece', Pest
Management Science, 69(7), pp. 834-84.
doi: 10.1002/ps.3442
Shalaby, S. E., Soliman, M. M., Ei-Mageed,
A. E. M. A. (2012) 'Evaluation of some
insecticides against tomato leaf minor
(Tuta absoluta) and determination of
their residues in tomato fruits', Applied
Biological Research, 14(2), pp. 113-119.