Evaluation of Attribute II Bt Sweet Corn Resistance and Reduced Risk Insecticide Applications for Control of Corn Earworm (original) (raw)
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Crop Protection, 2001
Twenty-eight transgenic maize hybrids containing the Bacillus thuringiensis (Bt) endotoxin and several of their non-Bt isolines were evaluated for control of the southwestern corn borer, Diatraea grandiosella Dyar, the European corn borer, Ostrinia nubilalis (HuK bner), and the corn earworm (CEW), Heliocoverpa zea (Boddie) in the shank and ear. The Bt hybrids represented four events (Mon810, Bt11, 176, and CBH354) from seven seed companies. The maize hybrids were grown in four locations that ranged from the northern to southern length of the Texas Panhandle. A semi-arid environment with hot days-cool nights and (220 mm of rain characterize this region. Maize in this region is irrigated with furrow or moving truss application systems. Maize was infested with each species of corn borer at the tasseling growth stage using the Davis applicator. Natural infestations of corn earworm were allowed to develop. Hybrids of events Mon810, Bt11, and CBH354 provided good control of corn borers in shanks and ears. Event 176 hybrids did not provide good control in the shanks and ears because Bt is not expressed in reproductive tissue in this event. No Bt transgenic maize hybrid provided consistent control of CEW larvae on kernels. Feeding gallery length on ears from CEW feeding was sometimes shorter in Mon810 and Bt11 hybrids than in the non-Bt hybrids.
Genetically Modified Maize Resistant to Corn Earworm (Lepidoptera: Noctuidae) in Sinaloa, Mexico
Florida Entomologist, 2015
Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), the corn earworm, is a key pest causing damage to corn Zea mays L. (Poales: Poaceae). The development of hybrids expressing Cry1Ab, Vip3Aa20, and mCry3A protein of Bacillus thuringiensis Berliner (Bt) (Bacillales: Bacillaceae) is an option to control this insect. Corn hybrids Agrisure TM 3000 GT, Agrisure® Viptera TM 3110, and Agrisure® Viptera TM 3111 were tested for corn earworm suppression in the agricultural region of Sinaloa during the 2011, 2012, and 2013 autumn-winter growing seasons, and compared with their respective isolines. Gallery length on the ear and the number of damaged ears were evaluated. The genetically modified hybrids demonstrated the effectiveness of inserted proteins to confer resistance to the corn earworm by killing the pest or reducing its growth and damage to the ear. Based on the results, Agrisure TM 3000 GT, Agrisure® Viptera TM 3110, and Agrisure® Viptera TM 3111 are useful elements for an integrated pest management program on corn in Sinaloa, Mexico.
Field-Evolved Resistance in Corn Earworm to Cry Proteins Expressed by Transgenic Sweet Corn
PloS one, 2016
Transgenic corn engineered with genes expressing insecticidal toxins from the bacterium Bacillus thuringiensis (Berliner) (Bt) are now a major tool in insect pest management. With its widespread use, insect resistance is a major threat to the sustainability of the Bt transgenic technology. For all Bt corn expressing Cry toxins, the high dose requirement for resistance management is not achieved for corn earworm, Helicoverpa zea (Boddie), which is more tolerant to the Bt toxins. We present field monitoring data using Cry1Ab (1996-2016) and Cry1A.105+Cry2Ab2 (2010-2016) expressing sweet corn hybrids as in-field screens to measure changes in field efficacy and Cry toxin susceptibility to H. zea. Larvae successfully damaged an increasing proportion of ears, consumed more kernel area, and reached later developmental stages (4th - 6th instars) in both types of Bt hybrids (Cry1Ab-event Bt11, and Cry1A.105+Cry2Ab2-event MON89034) since their commercial introduction. Yearly patterns of H. ze...
Journal of Insect Science, 2009
Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn.
Sustainability of insect resistance management strategies for transgenic Bt corn
Biotechnology Advances, 2003
Increasing interest in the responsible management of technology in the industrial and agricultural sectors of the economy has been met thorough the development of broadly applicable tools to assess the ''sustainability'' of new technologies. An arena ripe for application of such analysis is the deployment of transgenic crops. The new transgenic pesticidal or plant-incorporated protectant (PIP) crops have seen widespread application in the United States based on the features of higher yield, lower applications of insecticides, and control of mycotoxin content. However, open rejection of these new crops in Europe and in other countries has been a surprising message and has limited their worldwide acceptance. The US Environmental Protection Agency's (USEPA) Office of Pesticide Programs (OPP) has worked on the development and analysis of insect resistance management (IRM) strategies and has mandated specific IRM requirements for Bacillus thuringiensis (Bt) crops since 1995 under the Food, Fungicide, Insecticide, and Rodenticide Act. Improvement of data quality and sustainability of IRM strategies have been targeted in an ongoing partnership between the USEPA Office of Research and Development and the Office of Pesticide Programs that will further enhance the agency's ability to develop sustainable insect resistance management strategies for transgenic field corn (Bt corn) producing B. thuringiensis (Bt) insecticidal proteins.
Journal of Entomological Science, 2001
In 1998 and 1999, field studies were conducted near Rosemount, MN to assess the potential impact of transgenic sweet corn, transformed to express the Cry1Ab toxin from Bacillus thuringiensis Berliner var kurstaki (i.e., Bt corn), on several beneficial insects, including predatory coccinellids, chrysopids and anthocorids. Beneficial insects in both Bt and in non-Bt sweet corn were also monitored in field cages in 1999. Plants were visually sampled for beneficial insects by arbitrarily selecting 3 consecutive plants from each plot or 6 plants/cage. Rank transformed data were analyzed using the Kruskal-Wallis test, which indicated no significant within-year differences in the overall density of beneficial insect populations between Bt and non-Bt sweet corn. Coleomegilla maculata (DeGeer) was the dominant predator species detected in 1998 and 1999. A significant trend (P < 0.05) was found for C. maculata larvae in open plots, with non-Bt treatments having higher C. maculata levels th...
GM crops
Sweet corn, Zea mays L., transformed to express a novel vegetative insecticidal protein, Vip3A (event MIR162, Syngenta Seeds, Inc..), produced by the bacterium, Bacillus thuringiensis (Bt), was evaluated over four field seasons in Maryland and two field seasons in Minnesota for efficacy against the corn earworm, Helicoverpa zea (Boddie). Hybrids expressing the Vip3A protein and pyramided in hybrids also expressing the Cry1Ab Bt protein (event Bt11, ATTRIBUTE(®), Syngenta Seeds, Inc.) were compared to hybrids expressing only Cry1Ab or to genetically similar non-Bt hybrids each year. In addition to H. zea efficacy, results for Ostrinia nubilalis (Hübner) and Spodoptera frugiperda (J.E. Smith) are presented. Over all years and locations, the non-Bt hybrids, without insecticide protection, averaged between 43 and 100% ears infested with a range of 0.24 to 1.74 H. zea larvae per ear. By comparison, in the pyramided Vip3A x Cry1Ab hybrids, no larvae were found and only minimal kernel dama...