Fluctuation and vertical distribution of population of the brown root stink bug, Scaptocoris castanea Perty (Hemiptera: Cydnidae), within soil profile, in soybean fields in Mid Western and Southeastern Brazil

The temporal and spatial distribution patterns and annual population variation of the brown root stink bug, Scaptocoris castanea Perty, in the soil profile in different soybean regions in Brazil, were studied. Periodic samplings of bugs population were taken from December/98 to May/2000. In Sapezal, Mato Grosso state (12degrees59'W, 58degrees45'S), the highest adult population occurred from November to January, with peak on December, during the rainy season. The number of adults was higher than the number of nymphs from December to April; last instar nymphs were more abundant from June to October. Adults and all nymph stages were found until 1.2 m depth. However, during all year, 77% of the population was found above 60 cm. From May to October, more than 60% of the population was concentrated below 30 cm in the soil profile. In Candido Mota, Sao Paulo state (22degrees44'W, 50degrees23'S) from July to September, bugs were observed only until 70 cm depth, and, in average, 60% of the population was concentrated from 30 cm to 60 cm depth. In this region, adults were more abundant than nymphs only during May.