Orientation, feeding, and ovipositional behavior of diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), on transgenic cabbage expressing Cry1Ab toxin of Bacillus thuringiensis (Berliner)

Abstract

In the past few years, a number of transgenic plants expressing Bacillus thuringiensis (Bt) proteins have been commercialized throughout the world, particularly in the developed countries. In developing countries, the process of commercializing insect-resistant transgenic crops has begun and is likely to gain momentum in the near future. Resource-poor farmers who are unable to afford the cost of genetically modified (GM) seed fear that the pests will avoid GM fields and instead attack their non-GM fields. A study was conducted in India to elucidate whether pests will avoid the transgenic Bt crop and congregate in the fields with non-GM crops. Transgenic Bt cabbage and nontransgenic cabbage were compared for their suitability for oviposition, larval feeding, and orientation by the diamondback moth, Plutella xylostella, in the laboratory. Data presented in this study show that adult P. xylostella were equally attracted to transgenic and nontransgenic cabbage plants. Larval attraction to both types of plants was also equally high. After hatching on the transgenic cabbage plants, first instar larvae suffered 100% mortality and, therefore, did not move to nearby nontransgenic plants. However, the larvae released on the nontransgenic plant were attracted to transgenic plant placed in its vicinity and suffered heavy mortality.