Detection of Lesser Grain Borer Larvae in Internally Infested Kernels of Brown Rice and Wheat Using an Electrically Conductive Roller Mill

Abstract

Modifications were made to a small laboratory mill to enable the detection of rice kernels internally infested by immature grain insects. The mill, which was originally designed for wheat, monitors electrical conductance through the grain and detects kernels that are infested with live insects based on abrupt changes in electrical conductance as the insects inside the kernels are crushed between the mill rolls. The mill was adapted to detect rice infested by immature lesser grain borers (LGB) by altering the gearing and reducing the gap between the two mill rolls to produce shear between the rolls. Samples of LGB infested long, medium, and short grain (dehulled) brown rice and hard red winter wheat were tested in both the modified and original mills. The detection rates for long grain brown rice kernels infested with large, medium, and small LGB larvae were 97, 83, and 42%, respectively, with the modified mill and 61, 22, and 4%, respectively, with the original mill. Similar detection rates were observed ...