Pink Borer Sesamia Inferens Research Articles

Effect of host plant on growth, tissue proteins and gut enzymes of pink borer Sesamia inferens

In this study, pink borer Sesamia inferens (Walker), a polyphagous insect and a major pest on millets is explored for analysing the influence of host plants on the growth, tissue proteins and midgut digestive enzymes of their larvae. The impact of feeding on different food plants on the activity of amylase, trehalase, and invertase in the midgut of the final instar larvae were assayed in vitro. The results showed that the larval feeding on the five millet hosts had significant effect on body mass, with maximum body mass being achieved when larvae fed on sorghum (0.214 g). Significantly more enzyme activity of amylase was observed in the larvae fed on finger millet. The activity of amylase, invertase and trehalase fed on pearl millet was relatively low. The results indicated that the larvae of S. inferens had more capability to utilize sorghum, finger millet and barnyard millet, suggesting that these plants could become their host plants

Baseline sensitivity of lepidopteran corn pests in India to Cry1Ab insecticidal protein of Bacillus thuringiensis

Genetically engineered corn (Bt corn) expressing Bacillus thuringiensis Berliner insecticidal protein Cry1Ab is a biotechnological option being considered for management of lepidopteran corn pests in India. As a resistance management practice it was essential to determine the sensitivity of multiple populations of the stalk borer Chilo partellus (Swinhoe), pink borer Sesamia inferens (Walker) and the cob borer Helicoverpa armigera (Hübner) to Cry1Ab protein through bioassays. The insect populations were collected during growing seasons of Rabi 2005 (October 2005 to February 2006) and Kharif 2006 (May to September 2006). Multiple populations of the three lepidopteran corn pests were found to be susceptible to Cry1Ab. Median lethal concentrations (LC(50)) ranged between 0.008 and 0.068 microg Cry1Ab mL(-1) diet for 18 populations of C. partellus (across two seasons), between 0.12 and 1.99 microg mL(-1) for seven populations of H. armigera and between 0.46 and 0.56 microg mL(-1) for two populations of S. inferens. Dose-response concentrations for lethality and growth inhibition have been determined to mark baseline sensitivity of multiple populations of key lepidopteran corn pests in India to Cry1Ab protein. These benchmark values will be referenced while monitoring resistance to Cry1Ab should Bt corn hybrids expressing Cry1Ab be approved for commercial cultivation in India.