Insecticide Sequences on Lambda-Cyhalothrin Resistance in Whitefly Bemisia tabaci (Genn.)

Transcription

1 Academic Journal of Entomology 6 (1): 37-41, 2013 ISSN IDOSI Publications, 2013 DOI: /idosi.aje Insecticide Sequences on Lambda-Cyhalothrin Resistance in Whitefly Bemisia tabaci (Genn.) Sayeda F. Farghly Central Agricultural Pesticides Laboratory, Agricultural Research Center (ARC), Dokki, Giza, Egypt Abstract: A lab-strain of whitefly Bemisia tabaci (Genn) was selected for lambda-cyhalothrin and build-up resistance in the laboratory. Resistance was ( fold) after 10 generations. These strain showed there was no cross-resistance with different insecticides such as thiocyclam, buprofegin, acetamiprid, pymetrozin, pirimiphos-methyl, methomyl, carbosulfan. Proposal sequences of insecticides applications as strategy for resistance management showed that, the program with sequence of thiocyclam buprofezin, acetamiprid and pymetrozin was the best program. Key words: Bemisia tabaci Resistance Cross-resistance Sequence of insecticides INTRODUCTION seasons 2000 and 2001, particularly pyrethroids and organophosphates, resistance factors to the pyrethroid The whitefly Bemisia tabaci (Genn.) (Hemiptra: lambda-cyhalothrin was up to fold [5]. Alyrodidae) is one of the most damaging pests of In the present study, the level of resistance to numerous crops worldwide as well as Egypt. The abilityof lambda-cyhalothrin was estimated in population of B. tabaci to develop resistance to insecticides after only B. tabaci subsequent insecticide selection was carried a few applications makes its control problematic in the out to build up resistance and proposal sequences of long term [1]. The chemical control program followed insecticides application a strategy for resistance against different cotton pests led to the increase in management. infestation of cotton with whitefly, this status has been attributed for various factors. The wide-scale use of MATERIALS AND METHODS insecticides which disrupted the parasite and predator populations has enhanced whitefly fertility [2] and has led Bemsia tabaci Strains: Field strain of B. tabaci was to the development of resistance to most of insecticides used in conventional programmes [3,4]. Prolonged exposure of B. tabaci population to high dosages and collected from Beheira Governorate during the year of 2000 and maintained without insecticide selection pressure for more than 10 years in the Central frequent applications of insecticides is well known to Agricultural Pesticides Laboratory, Department of select for insecticide resistance. Monitoring high resistance levels to several insecticide classes in field B. tabaci populations from different governorates in Rearing Standard Insects. Resistant-strain derived from the lab-strain was selected with lambda-cyhalothrin as shown in Table 1. Table 1: Development of resistance in whitefly B. tabaci to lambda-cyhalothrin. Strain tested LC 50 (ppm) Slope ± SE Resistance ratio (RR 1) Lab-strain ± ± G ± G ± G ± G ± G ± RR1-LC 50 of resistant strain/lc 50 of the lab-strain Corresponding Author: Sayeda F. Farghly, Central Agricultural Pesticides Laboratory, Agricultural Research Center (ARC), Dokki, Giza, Egypt. 37

2 Insecticides Used: allowed to dry. The treated leaves were laid on a thin layer of 2% agar in small cage and then twenty adults were Pyrethroids: Lambda-Cyhalothrin (Karat, 20% EC). transferred into the cage by an aspirator. Mortality was Deltamethrin (Decis, 2.5% EC). recorded 24 and 48hr after treatment. Six concentrations at least were tested for each insecticide; each test was Neonicotinoids: replicated five different times. Results were expressed as percentage mortalities, corrected using [7]. Dinotefuran (MTI, 4% SG). Imidacloprid (Best, 25% WP). Selection Pressure: The population of the Acetamiprid (Mospilan, 20% SP). resistant-strain which consisted of many thousands was subjected to laboratory selection pressure with Miscellaneous: insecticide, at a level producing 30% mortality to the adult stage, developing resistance was determined for Thiocyclam (Evisect, 50% WP). generations 3, 6, 9 and 13. Resistance ratio (RR 1) was Pymetrozin (Chess, 25% WP). determined by dividing the LC 50 of the R-strain by the LC 50 of lab-strain. Cross-resistance to all different groups Insect Growth Regulators: of insecticides was investigated in the lambda-cyhalothrin whitefly resistance strains after reaching a Buprofegin (Apploud, 25% SC). significantly high level of resistance to both insecticides. Pyriproxyfen (Admiral, 10% EC). Testing technique (Bioassay) was the same as described before. Relative resistance (RR 2) was determined by Mineral Oil: dividing the LC 50's of the R-strain by the LC 50's of the field-strain. Kz Oil 95% EC Influence of Sequence Application of Strategy for Organophosphorus:- Insecticides on the Development of Resistance Insecticides Used: The highly efficient insecticides Profenofos (Selecron, 72% EC). were selected to apply in rotational manner and the Pirimiphos-methyl (Actellic, 50% EC). level of resistance to these chemicals was observed. These compounds represent all the main groups of Carbamates: insecticides. The used insecticides were thiocyclam (Evisect, 50% WP), buprofegin (Applaud, 25% SC), Methomyl (Lannate, 90% WP). Acetamiprid (Mospilan, 20% SP), pymetrozine Carbosulfan (Marshal, 25% WP). (Chess, 25% WP). Bioassay: The bioassay method for obtaining Bioassay Procedure: The R-strain was divided into four concentration-response regressions lines was described groups; each group was constituted of chemical control by Prabhaker et al. [6] with some modification; agent with different sequence system. The proposed attached cotton leaves were dipped for 5 sec. in 100 ml of programme of alternative use of the four insecticides is the desired concentration of each insecticide and presented in Table 2. Table 2: Proposed sequences of the tested insecticides The tested insecticides programs The different generations Program A Program B Program C Program D G1 Thioyclam Buprofezin Acetamiprid Pymetrozine G2 Buprofezin Acetamiprid Pymetrozine Thioyclam G3 Acetamiprid Pymetrozine Thioyclam Buprofezin G4 Pymetrozine Thioyclam Buprofezin Acetamiprid At the end of each program, the LC 50's were determined to calculate the level of resistance. 38

3 RESULTS AND DISCUSSION these data are in harmony with the results of Wang et al. [9], who found that, after resistance selection of Development and Cross-Resistance: Resistance ratio Aphis gossypii to imidacloprid for 12 consecutive for whitefly lambda-cyhalothrin strain as presented in generations on Cotton, resistance ratio 8.1-fold, on Table 1 (RR 1= fold) after selection for ten cucumber resistance to imidacloprid was 3.6-fold. generations. From these results, it is clear that selection R-imidacloprid strain exhibit Cross-resistance to pressure of laboratory population of whitefly with the fenvalerate, with a resistance ratio of fold on pyrethroid. Lambda-cyhalothrin resulted in the cotton and 33.5 fold on cucumber. Negative crossdevelopment of resistance to this insecticide, this may be resistance for R-strain was recorded in thiocycalm, explained by the fact that genes responsible for resistance pymetrozine, buprofezin and acetamipirid. These results to pyrethroids still exist within the population and the are of special interest indicating a possible alteration whitefly would be expected to have a head start in between these insecticides and lambda-cyhalothrin in developing resistance to pyrethroids. The results of insecticide-resistance management programs aiming cross-resistance are presented in Table 3. There is no at delaying resistance development to the novel groups cross-resistance between R-strain and deltamethrin; these of insecticides. results may be due to the difference in chemical structure in the ester-bonded. Yang et al. [8] reported that Proposal Sequences of Insecticide Application as resistance to fluchytrinate, fenvalerate and esfenalerate Strategy for Resistance Management: Adults of whitefly was higher than to permethrin, deltamethrin, bifenthrin in each group (from 10 generation of R-strain) were and cypermethrin against pyrethroid-resistant strain and exposed in consecutive application to the four selected they suggested that the acid moiety of pyrethroid insecticides in which each insecticide used once on the structure could be the key to selectivity in the esterase- consecutive four generations. The same cycle for each mediated pyrethroid resistance of Helicoverpa armigera. group was repeated and the level of resistance after each On the other hand, R-resistance has a highly cross- cycle was calculated, the results of each program as resistance to the neonicotinoids expect acetamiprid, presented in Tables 4, 5, 6 and 7. Table 3: Cross-resistance spectrum of lambada-cyhalothrin strain of the whitefly, Bemisia tabaci adults to certain insecticides. Insecticides Lab-strain LC 50 (ppm) Slope ± S.E R-strain LC 50 (ppm) Slope ± S.E RR1 Pyrethroids: Deltamethrin ± ± Neonicotinoids Dinotefuran ± ± Imidacloprid ± ± Acetamiprid ± ± Miscellaneous: Thiocyclam ± ± Pymetrozine ± ± Insect Growth Regulators: Buprofezin ± ± Pyriproxyfen ± ± Mineral oil: KZ oil ± ± Organophosphorus: Profenofos ± ± Pirimiphos-methyl ± ± Carbamates: Methomyl ± ± Carbosulfan ± ± RR 1: Resistance ratio. 39

4 Table 4: Program (A) Thiocyclam ± ± Buprofezin ± ± Acetamiprid ± ± Pymetrozine ± ± Table 5: Program (B) Buprofezin ± ± Acetamiprid ± ± Pymetrozine ± ± Thiocyclam ± ± Table 6: Program (C) Acetamiprid ± ± Pymetrozine ± ± Thiocyclam ± ± Buprofezin ± ± Table 7: Program (D) Pymetrozine ± ± Thiocyclam ± ± Buprofezin ± ± Acetamiprid ± ± Table 8: Effect of alternative application of-certain insecticides on the susceptibility of B. tabaci Program (A) Program (B) Program Program (D) Insecticides RR RR RR RR RR RR RR RR Thiocyclam Bubrofezin Acetamiprid Pymetrozin

5 In this connection data in Table 8 showed that, the 3. Watve, C.M., D.F. Clower and J.B. Graves, best program was in sequence of thiocyclam, buprofezin, Resistance to methyl parathion and monocorotophos acetampirid, pymetrozin (program A). Farghaly [5] in the banded-wing whitefly in Louisiana. J. Econ. showed that, the best treatment was in a sequence of Entmol., 70(2): lambada-cyhalothrin, profenofos, imidacloprid and 4. Elhag, E.A. and D.J. Horn, Resistance of buprofezin where the values of RR 1, were , 26.22, greenhouse whitefly (Homoptera: Aleyrodidae) to and fold, respectively, while RR 2 values insecticides in selected Ohio greenhouse. J. Econ. were 14.37, 4.60, 1.37 and fold, respectively. Entomol., 76: As insecticides are still needed in crop protection 5. Farghaly, S.F., Studies on profenofos and because of lack of alternative control methods in many thiamethoxam resistance in whitefly Bemisia cases, it is important to preserve their long-term tabaci. PhD Thesis. Agricultural Sciences. effectiveness, this can be done through insecticide Pesticides, Faculty of Agriculture, Cairo University. resistance management (IRM) programs, which are based 6. Prabhaker, N., D.L. Coudriet and D.E. Meyerdirk, on reduced reliance of pesticides, resistance monitoring Insecticide resistance in the sweet potato and rational insecticide use of existing compounds and whitefly. Bemisia tabaci (Hemiptera: Aleyrodidae). optimal use of new insecticides. J. Econ. Entomol., 78: REFERENCES 7. Abbott, W.S., A method of computing the effectiveness of an insecticide. J. Econ. Entomol., 18: Denholm, L., M. Cahill, T.J. Dennehy and 8. Yang, E., Y. Yang, S. Wu and Y. Wu, Relative A.R. Horowitz, Challenges with managing contribution of detoxifying enzymes to pyrethroid insecticide resistance in agricultural pests, resistance in a resistant strain of Helicoverpa exemplified by the whitefly Bemisia tabaci. Phil Trans armigera. J. Appl. Entomol., 129(9/10): Ray. Soc. London Ser. B-Biol. Sci., 353: Wang, K.Y., I.X. Liu, C.H. Yu. X.Y. Jiang and M.Q.. 2. Dittrich, V., S.O. Hassan and G.H. Ernst, Yi Resistance of Aphis gossypii (Homoptera: Sudanese cotton and the whitefly: a case study of Aphididae) to fenvalerate and imidacloprid and the emergence of a new primary pest. Crop. Prot., activities of detoxification enzymes on cotton and 4: cucumber. J. Econ. Entomol., 95(2):