Thermal energy obtained from either infrared or microwave radiation or from heat by convection can be used to control insects infesting stored products. The time required to obtain temperatures that are lethal to insects depends not only on the insect species but also on the moisture content and heat-retention characteristics of the grain or other commodities. An infrared heater with a surface temperature of 926 degrees C was tested; approximately 75% of its output was in the middle section of the infrared region; and peak emissions occurred at 2.5 microns. The eggs and young larvae of lesser grain borers, Rhyzopertha dominica (F.), and Angoumois grain moths, Sitotroga cerealella (Olivier), infesting wheat were more resistant to infrared radiation than were the eggs and young larvae of rice weevils, Sitophilus oryzae (L.). Microwave tests were conducted in an oven with a frequency of 2,450 MHz. The mature larvae and pupae of Angoumois grain moths, rice weevils, or lesser grain borers were more resistant to microwave energy than either the young larvae or eggs. Convected heat was tested using elevated temperatures obtained with a chamber maintained at a constant temperature and RH. Air temperatures of 39 degrees C with 60% RH gave 99% or more control of rice weevils, but a temperature of 43 degrees C and 50% RH were required for control of lesser grain borers. Wheat quality appeared unaffected by storage temperatures of 49 degrees C for either 1 or 2 months. However, the flour from this wheat did change color especially when the wheat samples were stored for 2 months.