Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.1639.1649Helicoverpa armigera to Spore-δ-endotoxin of Various Bacillus thuringiensis (Berliner)]]>AhmedKhalique KongmingW. U.LiangGemie GuoYuyuan 9200699The present study elaborates on the results of cross-resistance of Cry1Ac resistant Helicoverpa armigera (Hübner) to spore-δ-endotoxin complex of Bt strains (HD-1, HD-4, HD-8, HD-57, HD-133, HD-234, HD-263, HD-282, HD-551, HD-744 and Bt-based biopesticide. In this study, all the bioassays were done on larvae of 55 th, 0 th and 61st Cry1Ac selected generations of H. armigera. The resistance ratios (RR) among Cry1Ac selected generations varied from 172 to 417 fold in different generations. Cry1Ac selection exhibited low resistance ratios (2.722, .756) against HD-1 and HD-8 among all the HD strains tested and the slopes for HD-1 and HD-8 were highly significant (1.49 and 1.31, respectively). The test insect also showed low resistance ratios 3.959 and 4.385 for HD-551 and HD-57 respectively with significant slopes 1.18 and 2.36 accordingly. The spore-crystal toxins of strains of HD-1, HD-8, HD-263 and Bt-based biopesticide caused significant reduction in larval weight (%) with regressions y = 0.011x+93.912, R2 = 0.7269, df = 4, p<0.05 and y = 0.03x+85.332, R2 = 0.6982, df = 4, p<0.05, y = 0.0458x+79.58, R2 = 0.7271, df = 4, p<0.05 and y = 0.0776x+59.169, R2 = 0.8273, df = 4, p<0.05, respectively against Cry1Ac selection. Significant slopes 1.49, .31, .36, .67, .18, .12 and 2.09 for HD-1, HD-8, HD-57, HD-263, HD-551, HD-744 and Bt-based biopesticide, respectively indicated fast interaction between spore-crystal toxins of Bt strains and the Cry1Ac resistant insect. Similarly for susceptible H. armigera, significant regression trends in term of percent larval weight reduction were observed for HD-263 (equation y = 0.0374x+82.173, df = 4, p<0.05, R2 = 0.7098), HD-1 (y = 0.0501x+76.35, df = 4 p<0.05), HD-8 (y = 0.0584x+68.508, df = 4, p<0.05) and Bt-based biopesticide (y = 0.0968x+57.063, df = 4, p<0.05). Previous studies conducted by other workers indicated synergistic impact between spores and crystals of Bt strains against resistant insects. Present results suggest that the spore-crystal complex (perhaps due to synergistic interaction between or among the spore and crystal components) may have caused synergism due to which a Cry1Ac selection was knocked down. Thus, spore-crystal complex-based formulations of Bts can be developed for use as an effective tool to manage insect populations that have development resistance to single toxin (Cry1Ac) produced in transgenic crops (e.g., Bt-Cotton).]]>Abida, B.,2002Bacillus thuringiensis Berliner against chickpea pod borer, Helicoverpa armigera.]]>2002Ahmed, K., F. Khalique, B.A. Malik and D. Riley,1994Helicoverpa (Heliothis) armigera (Hubner).]]>463844Ahmed, K., F. Khalique and B.A. Malik,1998Bacillus thuringiensis and malic acid against chickpea pod borer, Helicoverpa armigera (Hubn.) Lepidoptera: Noctuidae.]]>111051115Ahmed, K.,1999Helicoverpa armigera, using pheromone traps and Bacillus thuringiensis Berliner.]]>1999Akhurst, R.J., W. James., L.J. Bird and C. Beard,2003Bacillus thuringiensis in the cotton boll worm, Helicoverpa armigera (Lepidoptera: Noctuidae).]]>9612901299Bolin, P.C., W.D. Hutchison and D.A. Andow,1999Bacillus thuringiensis Cry1Ac endotoxin in a Minnesota population of European corn borer (Lepidoptera: Crambidae).]]>9210211030Glenn, D.C., A.A. Hoffmann and G. McDonald,1994Helicoverpa armigera (Lepidoptera: Noctuidae) from corn: Adult resistance, larval resistance and fitness effects.]]>8711651171Gould, F., A. Anderson, A. Reynolds, L. Bumgarner and W. Moar,1995Heliothis virescens (Lepidoptera: Noctuidae) strain with high level of resistance to Bacillus thuringiensis toxins.]]>8815451559Gould, F. and B.E. Tabashnik,19981998pp: 76-105.pp: 76-105.Liang, G.M., W.J. Tan and Y. Guo,1999251517Liang, G., W.J. Tan and Y. Guo,2000Bacillus thuringiensis (Berliner).]]>334653Liang, G. and Y. Guo,20022002Liao, C., S.C. Trowell and R.J. Akhurst,1996Bacillus thuringiensis insecticidal crystal proteins to the cotton bollworm, Helicoverpa armigera.]]>1996pp: 180192Liao, C., D.G. Heckel and R.J. Akhurst,2002Bacillus thuringeinsis insecticidal proteins for Helicoverpa armigera and Helicoverpa puntigera (Lepidoptera: Noctuidae), major pests of cotton.]]>805563Liu, Y.B., B.E. Tabashnik, W.J. Moar and R.A. Smith,1998Bacillus thuringiensis spores and toxins against resistant and susceptible diamondback moth (Plutella xylostella).]]>6413851389Liu, Y.B., B.E. Tabashnik, T.J. Dennehy, A.L. Patin, M.A. Sims, S.K. Meyer and Y. Carriere,20019412371242Luttrell, R.G., L. Wan and K. Knighten,1999Bacills thuringeinsis.]]>922132McGaughey, W.H. and D.E. Johnson,1987Bacillus thuringiernsis to resistant and susceptible Indianmeal moth (Lepidoptera: Noctuidae).]]>812833Miyasono, M., S. Inagaki, M. Yamamoto, K. Ohba, T. Ishiguro, R. Takeda and Y. Hayashi,1994Bacillus thuringiensis against the diamondback moth, Plutella xylostella.]]>63111112Muller-Cohn, J., J. Chaufaux, C. Buisson, N. Glois, V. Sanchis and D. Lereclus,1996Spodoptera litoralis (Lepidoptera: Noctuidea) resistance to Cry1C and cross-resistance to other Bacillus thuringiensis crystal toxins.]]>89791797Padidam, M.,1992Bacillus thuringiensis is highly toxic for Heliothis armigera.]]>59109111Qu, X., Y. Jiang and R. Zhang,2001213739Tabashnik, B.E.,1992Bacillus thuringiensis toxins.]]>5833433346Tabashnik, B.E.,1994Bacillus thuringiensis.]]>394779Tabashnik, B.E., Y.B. Liu, T. Malvar, D.G. Heckel, L. Masson and J. Ferre,1998Bacillus thuringiensis: Uniform or diverse?]]>35317511756Tang, J.D., A.M. Shelton, J. van Ric, S. De Roeck, W.J. Moar, R.T. Roush and M. Peferoen,1996Bacillus thuringiensis spore and crystal protein to resistant diamondback moth (Plutella xylostella).]]>62564569Tariq, M.,2001Bacillus thuringiensis berliner.]]>2001Wu, K. and Y. Guo,1997Helicoverpa armigera.]]>403034Wu, K., G. Liang and Y. Guo,1997Helicoverpa armigera (Lepidoptera: Noctuidea), in China.]]>90868872Wu, K., Y. Guo, N. LV, J.T. Greenplate and R. Deaton,2002Helicoverpa armigera (Lepidoptera: Noctuidae) to Bacillus thuringeinsis insecticidal protein in China.]]>95826831Wu, K., Y. Guo and W. Wang,2000Helicoverpa armigera.]]>27317321Ahmed, K.,1995Bacillus thuringiensis and Heliothis Nuclear Polyhedrosis Virus (HNPV).]]>1st Edn.,pp: 1-6pp: 1-6Ahmed, K., F. Khalique, B.A. Malik and D.N. Ferro,1996Helicoverpa (Heliothis) armigera (Hubn.) to HD-1-S-1980 and relative toxicities of commercial Bacillus thuringiensis.]]>1996pp: 579594Ahmed, K., F. Khalique and B.A. Malik,1997Helicoverpa armigera on chickpea in Northern Pakistan.]]>1997Anonymous,19871st Edn.,Mrakwick, N.P., R.M. Simpson, D.M. Sucking, C.M. Frater, P.J. Wigley and L.C. Docherty,2002Bacillus thuringiensis) in leaf-roller Epiphyas postvittana (Walker).]]>2002pp: 6971