BIOLOGICAL CONTROL OF PEST INSECTS IN ORGANIC SOYBEANS IN THE DISTRITO FEDERAL

Abstract

The expansion of soybeans in organic systems, to supply the rising worldwide demand of these products, depends on development of pest management methods in accordance of rules established for certification organisms. An evaluation of the pest insect populations and biocontrol methods were done in an organic soybean field of Distrito Federal, in order to help local farmers and extension technicians. Bioinsecticides of Bacillus thuringiensis and Baculovirus anticarsia were sprayed to hold the outbreak of velvet bean caterpillar, Anticarsia gemmatalis, and to avoid economic damage for the crop. Both bioinsecticides were able to controll the pest producing mortality rates of 86 and 76% respectively. The stinkbugs are the main pest during the reproductive stage of soybean and the main species present in the area were Euschistus heros, Piezodorus guildinii e Nezara viridula. The stinkbugs control was provide through the preventive release of egg parasite wasps, Telenomus podisi. The population of stinkbugs in the soybean field was kept bellow the average 0,5 stinkbugs per sampling coat until the harvest. As a result no other control measure was required. The economic analysis showed that the pest biocontrol methods proposed in this study presented costs compatible with the total cost of the crop and its profitability.