Principais pragas e inimigos naturais nas culturas do milho, Zea mays L., e feijão, Phaseolus vulgaris L., em monocultivo e consorciadas, em Lavras-Minas Gerais

Abstract

The present work was carried out in an experimental area on the campus of the Escola Superior de Agricultura de Lavras-MG, from December 1987 to May 1988. The objective of this work was to investigate the occurrence of pests and natural ene mies in crops of maize and beans in monocultural and intercrop systems. A randomized blocks design was used, with six replicates. The treatments consisted of 1 - maize monoculture; 2 - beans and maize consortium in the same row; 3 - beans and maize consortium in alternate rows (1 row of bean to 1 row of maize); 4 - beans in monoculture. The occurrence of pests and natural enemies in maize was not affected significantly by the cropping systems tested, except for Maecolaspis joliveti (Coleoptera-Chrysomelidae), whose population density was the lowest in monoculture, and of Hélio this zea (Lepidoptera-Noctuidae), whose population density was the lowest in treatment (3). In beans, the occurrence of Empoasca kraemeri (Homopte ra-Cicadellidae) was lower in intercrops systems in comparison with the monocultural system, however in the criticai period of the occurrence from this pest, there were no differences between planting systems. Other pests and natural enemies in beans showed occurrence analagous between the cropping systems analysed, ex cept the occurrence of the predator Cycloneda sanquinea (Coleoptera-Coccinellidae) which was higher in the intercrop system withthe crops in the same row.