Search

Abstract: Spodoptera cosmioides (Walker), Spodoptera eridania (Stoll) and Spodoptera frugiperda (J. E. Smith) have caused significant damage on soybean Glycine max (L.) Merrill in Brazil. Genetically-modified MON 87701 × MON 89788 soybean that expresses the Cry1Ac protein is potentially an alternative tool for the management of these species. Purified protein bioassays were done to evaluate the susceptibility of S. cosmioides, S. eridania and S. frugiperda to Cry1Ac protein. The level of efficacy of the Bt soybean plants in controlling these species was measured through laboratory and greenhouse trials under high artificial insect infestations. The biology of these insects was evaluated over their development cycles to understand their life history when fed on Bt soybean. Purified Cry1Ac protein at the maximum concentration tested (100 μg Cry1Ac mL−1 diet) resulted in low mortality of S. cosmioides and S. eridania (<13%) and intermediate mortality of S. frugiperda (50%). No significant effects of the Bt soybean plants were observed in the life table parameters of S. cosmioides and S. eridania. However, S. frugiperda fed on Bt soybean plants had a prolonged larval stage (by 5 days), reduced larvae viability, increased mean generation time (by 8 days) and reduced intrinsic rate of increase. In general, the Bt soybean plants showed poor control of Spodoptera species when evaluated by leaf-disc bioassay and greenhouse trials. Consequently, other control tactics must be used in combination with MON 87701 × MON 89788 soybean in the field for the efficient management of S. cosmioides, S. eridania and S. frugiperda. [Copyright &y& Elsevier]

Background Genetically modified MON 87701 × MON 89788 soybean ( Glycine max) that expresses the Cry1Ac and EPSP-synthase proteins is a new Integrated Pest Management ( IPM) tool for controlling Heliothis virescens in Brazil. To Support Insect Resistance Management ( IRM) programs and understand the value of this event for IPM, we conducted laboratory and field studies to assess the biological activity of Cry1Ac protein expressed on Bt soybean against this insect pest. Results Heliothis virescens was highly susceptible to purified Cry1Ac protein [ LC50 ( FL 95%) = 0.026 (0.021-0.033) µg Cry1Ac mL-1 diet]. In bioassays with freeze-dried MON 87701 × MON 89788 soybean tissue diluted 25 times in an artificial diet, there was 100% mortality of H. virescens. In bioassays with leaf disc, young trifoliate, flower buds, pods and high artificial infestation under greenhouse condition, MON 87701 × MON 89788 soybean showed a high level of control against H. virescens. Moreover, larvae from first through fifth instar were highly susceptible to MON 87701 × MON 89788 soybean. Conclusions The MON 87701 × MON 89788 soybean provides an effective alternative in controlling Heliothis virescens and complies with the concept of high-dose for IRM programs. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Genetically modified MON 87701 × MON 89788 soybean ( Glycine max), which expresses the Cry1Ac and EPSP-synthase proteins, has been registered for commercial use in Brazil. To develop an Insect Resistance Management (IRM) program for this event, laboratory and field studies were conducted to assess the high-dose concept and level of control it provides against Anticarsia gemmatalis and Pseudoplusia includens. RESULTS: The purified Cry1Ac protein was more active against A. gemmatalis [LC50 (FL 95%) = 0.23 (0.15-0.34) µg Cry1Ac mL−1 diet] than P. includens [LC50 (FL 95%) = 3.72 (2.65-4.86) µg Cry1Ac mL−1 diet]. In bioassays with freeze-dried MON 87701 × MON 89788 soybean tissue diluted 25 times in an artificial diet, there was 100% mortality of A. gemmatalis and up to 95.79% mortality for P. includens. In leaf-disc bioassays and under conditions of high artificial infestation in the greenhouse and natural infestation in the field, MON 87701 × MON 89788 soybean showed a high level of efficacy against both target pests. CONCLUSIONS: The MON 87701 × MON 89788 soybean provides a high level of control against A. gemmatalis and P. includes, but a high-dose event only to A. gemmatalis. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Copyright of Revista de Economia e Sociologia Rural is the property of Sociedade Brasileira de Economia e Sociologia Rural and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)