Mutational disruption of the ABCC2 gene in fall armyworm, Spodoptera frugiperda, confers resistance to the Cry1Fa and Cry1A.105 insecticidal proteins.

The use of Bt proteins in crops has revolutionized insect pest management by offering effective season-long control. However, field-evolved resistance to Bt proteins threatens their utility and durability. A recent example is field-evolved resistance to Cry1Fa and Cry1A.

Characterization of the Activity Spectrum of MON 88702 and the Plant-Incorporated Protectant Cry51Aa2.834_16.

The spectrum of insecticidal activity of Cry51Aa2.834_16 protein targeting hemipteran and thysanopteran insect pests in cotton was characterized by selecting and screening multiple pest and non-pest species, based on representation of ecological functional groups, taxonomic relatedness (e.g.

Field-evolved resistance: assessing the problem and ways to move forward.

"Field-evolved resistance" is defined as a "genetically based decrease in susceptibility of a population to a toxin caused by exposure to the toxin in the field." The key component of "field-evolved" resistance is that it does confer decreased susceptibility to an insecticide in the field. Another key component is that the decrease in susceptibility to the insecticide is because of previous exposure of the target insect to the toxin in the field.

The design and implementation of insect resistance management programs for Bt crops.

Cotton and corn plants with insect resistance traits introduced through biotechnological methods and derived from the bacterium Bacillus thuringiensis (Bt) have been widely adopted since they were first introduced in 1996. Because of concerns about resistance evolving to these Bt crops, they have been released with associated IRM programs that employ multiple components and reflect the input of academic, industrial and regulatory experts. This paper summarizes the current status of Bt crop technologies in cotton and corn, the principles of IRM for Bt crops and what they mean for the design of IRM programs.

Efficacy of transgenic cotton containing a cry1Ac gene from Bacillus thuringiensis against Helicoverpa armigera (Lepidoptera: Noctuidae) in northern China.

NuCOTN 33B, a Bt transgenic variety of upland cotton (Gossypium hirsutum L.) expressing the insecticidal protein Cry1Ac from Bacillus thuringiensis Berliner sp. kurstaki, was evaluated for resistance to Helicoverpa armigera (Hübner) during 1998-2000 in northern China.

Resistance monitoring of Helicoverpa armigera (Lepidoptera Noctuidae) to Bacillus thuringiensis insecticidal protein in China.

Sensitivities of Helicoverpa armigera (Hübner) field populations to Bacillus thuringiensis (Bt) insecticidal protein CrylAc were monitored during 1998-2000 in China. A total of 41 strains was sampled, and most of them were collected from Bt cotton planting regions. The range of IC50 values (concentration producing 50% inhibition of larval development to third instar) among different populations in 1998,1999, and 2000 were 0.