This work was carried out in Coimbra, MG,Brazil, during the agricultural year of 1996/97 and it had the objective of evaluating the phytophagous insects and predators occurrence in maize and bean cultivated in exclusive and policultive systems. One cultivation of maize (from 10/25/1996 to 03/24/1997) and two cultivation of bean were conducted [the first one from 10/25/1996 to 01/20/1997 (rainy period cultivation) and the second one from 03/25/1997 a 07/21/1997 (drought period cultivation)]. The population of phytophagous insects and predators incident in the cultures were counted directly. Lower herbivores population density, which attacks preferentially maize [Dalbulus maidis (Delong & Wolcott) (Homoptera: Cicadellidae) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)] and bean [Diabrotica speciosa (Germ.), Cerotoma arcuata (Oliv.) (Coleoptera: Chrysomelidae) and Empoasca kraemeri (Ross & Moore) (Homoptera: Cicadellidae)] were associated to the intercropped system. The generalists-insect densities as Thrips tabaci Lind. (Thysanoptera: Thripidae) and Pseudoplusia includens (Walk.) (Lepidoptera: Noctuidae) were higher in the bean intercropped with maize. The phytophagous-insect total number was higher in the bean intercropped with maize in the rainy period cultivation than in the bean cultivated exclusively. The opposite happened in the drought period cultivation. The predators Anthicus sp. (Coleoptera: Anthicidae) and Hymenoptera: Formicidae were more abundant in the maize and bean cultivated exclusively than when the cultures were cultivated intercropped.
Insecta; Zea mays; Phaseolus vulgaris; herbivores; natural enemies
