Biology, Behavior, and Pest Detection on Stored Grain

In the tropics, insect pests account for large losses of food grains and other commodities. The knowledge of the biological parameters to establish suitable models of growth becomes necessary for programs of integrated pest management. Some insect pests of stored products can attack the grains in the field and in the wharehouse, as it happens with the Cathartus quadricollis (Guerin-Meneville). In Brazil, surveys showed the presence of this insect in the field. However, surveys evidencing the presence of this species in grains during the storage are lacking. Due to the occurrence of C. quadricollis in stored grains, the determination of their biological parameters such as the population growth becomes necessary. We determined the instantaneous rate of population increase (ri) of C. quadricollis, natural mortality and grain loss in three different stored grains. The experiment on population growth and grain loss was carried out using Petri dishes with 40 g of broken maize, wheat and sorghum grains (13 % moisture content). Ten Petri dishes were infested with 20 non-sexed adults (2-4 weeks old) at 25 ºC and 70 % RH. The number of alive and dead insects was counted after 60 days. Insects on broken maize showed a higher ri. Insects on wheat and sorghum showed the smallest ri. The wheat and sorghum grains showed the higher weight loss among the three feeding substrate. The insect natural mortality was higher on wheat grains