Baseline susceptibility to the Cry1Ab delta-endotoxin from Bacillus thuringiensis (Berliner) was determined for four populations of Sesamia nonagrioides (Lefebvre) and two populations of Ostrinia nubilalis (Hübner) from Spain. This study shows that S. nonagrioides is at least as susceptible as O. nubilalis to B. thuringiensis Cry1Ab protein. We found small differences in susceptibility among th...

BACKGROUND Bacillus thuringiensis Cry toxins are used worldwide in the control of different insect pests important in agriculture or in human health. The Cry proteins are pore-forming toxins that affect the midgut cell of target insects. It was shown that non-toxic Cry1Ab helix α-4 mutants had a dominant negative (DN) phenotype inhibiting the toxicity of wildtype Cry1Ab when used in equimolar o...

Tomanage insect resistance to transgenic crops that express insecticidal proteins from Bacillus thuringiensis (Bt) Berliner, the U.S. Environmental Protection Agency recommends a refugebased insect resistance management strategy where a percentage of non-Bt (refuge) crop is grown in proximity to a Bt-expressing crop. An important requirement for this strategy is that the toxin exists at a high ...

A 6-year field monitoring study was designed to compare the presence of fall armyworm Spodoptera frugiperda (J. E. Smith), leaf injury, its parasitoids, 100 seed weight, and yield Bt maize hybrids approved for commercialization in Brazilian market. Field trials were planted two municipalities, divided into periods, from 2011 2014 (period I), due approval different hybrids, 2015 2016 II). Treatm...

through an application of genetic engineering, genes from a soil bacterium bacillus thuringiensis (bt) which confer resistance to pests were transferred into rice. successful employment of genetic engineering in traditional breeding programs is dependent upon stable transmission of transgene in transgenic varieties. three different segregating f2 populations were developed from a cross between ...

Sesamia nonagrioides is one of the most damaging pests of corn in Spain and other Mediterranean countries. Bt corn expressing the Bacillus thuringiensis Cry1Ab toxin is being grown on about 58,000 ha in Spain. Here we studied the mode of action of this Cry protein on S. nonagrioides (binding to specific receptors, stability of binding, and pore formation) and the modes of action of other Cry pr...

We quantiÞed variation in performance under greenhouse conditions among seven populations of Scirpophaga incertulas (Walker) from Luzon Island, Philippines, on three rice varieties: ÔIR58Õ transformed with the cry1Ab gene from Bacillus thuringiensis Berliner, and nontransgenic IR58 and IR62. On IR62, S. incertulas performance did not differ among provinces for any of the 10 parameters measured,...

Lessons from organophosphorus pesticides, which could be bioaccumulated in non-target organisms at different trophic levels and caused unexpected negative impacts, necessitate a study of the possibility of biotransfer and bioaccumulation of Bacillus thuringiensis (Bt) insecticidal toxin(s) expressed in Bt plants. Using ELISA, we evaluated the transfer of Cry1Ab toxin in a food chain of Bt rice ...

The potential of Bacillus thuringiensis Cry proteins to control the grape pest Lobesia botrana was explored by testing first-instar larvae with Cry proteins belonging to the Cry1, Cry2, and Cry9 groups selected for their documented activities against Lepidoptera. Cry9Ca, a toxin from B. thuringiensis, was the protein most toxic to L. botrana larvae, followed in decreasing order by Cry2Ab, Cry1A...