Efficacy of crude extracts of Andrographis paniculata nees. on Callosobruchus chinensis L. during post harvest storage of cowpea.

Bioefficacy of different solvent fractions of A. paniculata was tested against the cowpea weevil, C. chinensis in terms of its effect on adult mortality, total egg output and emergence of F1 adults. All the extracts were effective against the weevil, the efficacy was however more significant with respect to methanol and ethyl acetate extracts at the highest concentrations (1,000 ppm) which lead to 72.01 and 67.69% adult mortality respectively. The efficacy was dose dependent. Total egg and percent emergence of Fl adults were lowest for methanol followed by ethyl acetate fractions. Possible role of the principal chemical constituents of this plant in bringing about mortality of the pest, reduction in egg laying and adult emergence are discussed.