Do green lacewings ('Mallada signata') add mortality of 'Helicoverpa armigera' on transgenic Bt cotton?

Abstract

Experiments were done to study the compatibility of a general predator, a green lacewing, to control 'Helicoverpa armigera' eggs and larvae with transgenic Bt cotton. Bt cotton did not affect green lacewing performance. Green lacewings consumed statistically identical numbers of 'Helicoverpa' eggs and larvae on both Bt and conventional cotton plants. On Bt cotton plants 83% of the 'H. armigera' larvae died within 72 hours. Mortality increased to 98% when lacewing larvae were present. This 'mopping-up' of surviving 'Helicoverpa' on Bt cotton by lacewing larvae has the potential to reduce immediate pest damage but perhaps more importantly remove potentially Bt-resistant genotypes.