Adeel Rehan

7/30/2019 Adeel Rehan

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Baseline susceptibility and stability of insecticide

resistance in Spodoptera litura(F.)

Adeel Rehan, Mushtaq A. Saleem, Sarfraz A. Shad, Ghulam M. Cheema andUmair Faheem

University College of Agriculture, B. Z. University, Multan


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Introduction

Polyphagous defoliating insect pest found in Asia andOceania

Important crops which are attacked in Pakistan arecotton, berseem, maize, tobacco, groundnut, summer

legumes, and vegetables such as cucurbits, brinjal,potato, sweet potato, and brassica

May cause 26100% yield loss in the field

High resistance against conventional insecticides

Low to medium resistance against new chemistryinsecticides


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Life stages ofSpodoptera litura

Larva Eggs

PupaeMoths


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Main Objectives

To generate the baseline susceptibility data ofS. lituraagainst four different insecticides i.e. spinosad, emamectinbenzoate, imidacloprid and profenofos

To observe the susceptibility of succeeding generations ofS. liturato different insecticides under laboratoryconditions

To check the stability of insecticide resistance in S. litura


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Materials and Methods

Larvae ofS. liturawere collected from dunyapur

The larvae were reared on improved artificial diet at27C2 temperature and 70-80% humidity

Toxicological studies Insecticides

Spinosademamectin benzoateprofenofosimidacloprid

Bioassay methodDiet incorporation method

Data analysis


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7.77

4.57 4.72

3.95

2.53

1.66

1.140.79

0

1

2

34

5

6

7

8

910

LC50v

alue(ppm)

1 4 5 7 8 9 10 11Generations

Toxicity of spinosad against Spodoptera lituraunder laboratoryconditions

Results


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3.85

1.371.14 1.19 1.13

0.70.4 0.33

0

1

2

3

4

5

6

LC50

va

lue(ppm)

1 4 5 7 8 9 10 11

Generations

Toxicity of emamectin benzoate against Spodoptera lituraunderlaboratory conditions


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258.75

136.5

52.07 49.840.71

24.6219.61 18.71

0

50

100

150

200

2503

00

LC50value(ppm)

1 4 5 7 8 9 10 11Generations

Toxicity of profenofos against Spodoptera lituraunder laboratoryconditions


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686.5

359.3

314.7

134.6 131.896.1

75.14 73.5

0

10020030040

0500600700800

LC50

value(ppm)

1 4 5 7 8 9 10 11

Generations

Toxicity of imidacloprid against Spodoptera lituraunder laboratoryconditions


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Insecticides Susceptibility Index Resistance Decline

Initial LC50

(ppm)

Final LC50

(ppm)

RF R G

imidacloprid 686.5 73.5 9.34 -0.088 11.36

spinosad 7.77 0.79 9.83 -0.090 11.11

emamectin

benzoate 3.85 0.33 11.7 -0.096 10.41

profenofos 258.75 18.71 13.8 -0.104 9.61


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Conclusion

This baseline susceptibility data can be used for futureinsecticide monitoring ofS. litura

S. liturahas resistance against non-target insecticide

(imidacloprid) that may cause cross resistance problems.


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Adeel Rehan