Interaction between Host Plant Resistance and Biological Activity of Bt in Managing the Pod Borer in Chickpea

Reports have shown that the legume pod borer (Helicoverpa ermigera) has developed high resistance to commercial insecticides. Thus, various efforts on producing chickpea producing toxin from Bacillus thuringiensis (Bt) are currently on going. However, scientists worry that the acid exudates in chickpea might interfere with the biological activity of Bt.

To clarify this apprehension, V. Surekha Dev from International Crops Research Institute for the Semi-Arid Tropics and two other scientists studied the biological activity of Bt on four chickpea genotypes with varied levels of resistance to H. armigera under field conditions. They also added freezed-dried leaf and pod tissues into the artificial diet with and without Bt. The predominant acids in the exudates were malic and oxalic acids. There was lower biological activity of Bt in diets containing chickpea leaf/pod powder than in the control. This may be attributed to the biological components of chickpea. Host plant resistance to H. ermigera in chickpea did not affect the biological activity of Bt. The findings suggest that the development of Bt chickpea could possibly be used to control the spread of legume pod borer.

Read the abstract at http://dx.doi.org/10.1016/j.cropro.2011.03.018.