NATURAL CONTROL OF Helicoverpa armigera (LEPIDOPTERA: NOCTUIDAE) PUPAE IN ORGANIC AND CONVENTIONAL MAIZE CROPS

Abstract

The natural biological control of soil pests is poorly studied. Notably, the control of Helicoverpa armigera in the pupae stage is unknown. To increase knowledge about the control of this pest in organic and conventional maize crop, tests were conducted to verify if the duration of pupae availability in days, the type of crop treatment (organic and conventional), the stage of crop development, and the depth of the soil significantly affect predation by natural enemies. The pupae availability time (days) in the soil did not affect their removal by natural enemies. However, in the fallow stage, on the surface and in the reproductive phase, the predation was higher. In organic maize, predation was 15% higher when compared to conventional maize. The rupture of the soil and the possible losses associated with beneficial fauna were the main factors responsible for higher predation during fallow, so conservationist practices usually used in organic treatment are the main reason for higher predation in this type of crop. There is a significant decrease in the control of H. armigera pests by natural enemies when maize is grown using conventional practices, what reinforces the importance of the conservation techniques used in maize crops.