SUMMARY The influence of soil and crop management systems on underground insects was evaluated, in Cruz Alta, Brazil, from February 1987 to August 1990. Soil samples were collected monthly and insects were separated and indentified. A greater number of insects was observed in no-till sowing system (MT), with 62.0% of the total. Larvae of elaterids, Acrolophus sp., Diloboderus abderus and Pantomorus Sp., as well as adults of Ataenius sp., Blapstinus punctulatus and Cyrtomenus mirabilis, showed a higher ocurrence frequency in the NT, while larvae of Diabrotica speciosa and Elasmopalpus lignosellus was more frequent in the conventional-tillage system (CT). A greater number of insects was found in the soybean-soybean-corn crop management, with 58.7% of the total, when compared to soybean grown continuously, and wheat-oat-vetch crop management, with 35.9%, when compared to wheat grown continuously and in wheat-oat, due to the high frequency of Diabrotica speciosa larvae in these systems.
tillage systems; crop systems; soil insects
