Biological aspects of Sternechus subsignatus Boheman (Coleoptera: Curculionidae) were investigated in commercial fields cultivated to soybean (Glycine max L.) under no-tillage system, in Rio Grande do Sul State, from November 1989 to December 1991. S. subsignatus showed one generation a year, with the stages occurring in well defined dates: adults were found form December to March, eggs and larvae in the plants from December to April, larvae in the soil from February to November and pupae and adults in the soil from September to December. The larval stage, in the soil, was the longest period of the life cycle. The duration stage of adults females and males in the plants was 112.5 and 62.9 days, respectivelly. The average number of eggs per female was 158.4 and egg viability was the 89.9%.
Sternechus subsignatus; evolutive cycle; tillage system
