Efficacy of helicoverpa armigera (hubner) on conventional and genetically modified cotton from Jalna district

Abstract

The present study deals with efficacy of cotton bollworms, Helicoverpa armigera (Hubner), on conventional, and Genetically Modified (GM) cottons plants, (Gossypium hirsutum L.) from Jalna District. This study was carried out both in field as well as laboratory experiments. The neonate larvae of Helicoverpa armigera were placed on the selected components of cotton squares and flowers of conventional, and Genetically Modified (GM) cotton varieties, we found that the survival of Helicoverpa armigera was greater on flower anthers and square anthers than on other floral parts for each cotton cultivar. The survival of Helicoverpa armigera was found lowest on all Bollgard® floral structures. On Bollgard® cotton plants, more larvae were recovered from white flowers and bolls. To quantify injury from bollworms on Bollgard® and Bollgard® II cottons plants, I instar larvae were placed in white flowers of conventional, Bollgard®, and Bollgard® II cottons plants. Bollworms damaged proximately two and three times more fruiting forms on conventional cotton plants than on Bollgard® and Bollgard® II cotton plants, respectively. To evaluate the influence of alternate hosts on bollworm sensitivity to conventional and Bollgard® cottons plants, host colonies were established on field grain sorghum, corn, Zea mays L.; soybean, Glycine max (Merrill); Sorghum bicolor (Moench); conventional cotton plants; and meridic diet. For the evaluation of larval behavior on Bollgard® cotton plant, first instar of Helicoverpa armigera were placed on terminals of non-flowering and flowering cotton plants. Larvae were recovered lower on Bollgard® cotton plants than on conventional cotton plants. Larvae remained near the terminals of conventional cotton plants feeding on terminal foliage and squares. In this study, we found that the field corn and grain sorghum was the best hosts for Helicoverpa armigera larvae than the cotton plants. Neonate larvae of Helicoverpa armigera, from each colony were placed on terminal foliage from conventional