Deterrence of oviposition of adult Ostrinia nubilalis Hubner (Lepidoptera: Pyralidae) by a natural enemy food supplement Envirofeast® on maize in France.

Oviposition deterrent activity of a natural enemy food supplement, Envirofeast, against Ostrinia nubilalis Hubner females was studied in choice and no-choice tests under laboratory conditions. Maize plants treated with Envirofeast at 25-40 g a.i./l had significantly fewer egg masses per leaf and eggs per egg mass laid on them compared with the untreated control plants in both choice and no-choice tests. However, maize plants treated with Envirofeast concentrations of 10-20 g a.i./l did not significantly deter the insect's oviposition. The optimum rate at which Envirofeast could deter oviposition was 25 g a.i./l. Increasing the rate of Envirofeast application from 25 g to 40 g a.i./l did not significantly increase its oviposition deterrent activity against O. nubilalis. However, reducing the rate from 25 to 20 g a.i./l resulted in a significant reduction in the oviposition deterrent activity of Envirofeast. The egg masses laid by O. nubilalis on Envirofeast treated plants were essentially (80%) located on ...