U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Document Type


Date of this Version



Insect Science (2008) 15, 455-460


© 2008 The Authors

This document is a U.S. government work and is not subject to copyright in the United States.

DOI 10.1111/j.1744-7917.2008.00233.x


Adults of Rhyzopertha dominica (F.), the lesser grain borer, were exposed on four varieties of rough rice with Dobie indices of susceptibility of 1.1 to 1.1 (low), and four varieties with Dobie indices of susceptibility of 3.4 to 3.8 (high). The varieties with low and high Dobie indices were classified as resistant and susceptible, respectively, to R. dominica. The purpose of the study was to evaluate control of R. dominica through the use of diatomaceous earth (DE) in combination with rice varieties that were either susceptible or resistant to R. dominica. The rice was treated with varying rates of the commercial DE Insecto®, up to a maximum of 1 000 mg DE/kg of rice. Adult mortality at each application rate of DE was generally greater on three of four resistant varieties compared to three of four susceptible varieties. Progeny production from the parental generation exposed on the rice was also greater in 3 of the 4 resistant varieties compared to 3 of the 4 susceptible varieties at DE rates of 500 mg/kg or more. Progeny production in rice treated with a maximum rate of 1000 mg/kg DE ranged from 7-44 adults on the resistant varieties compared to 75-155 adults on the susceptible varieties. At DE rates of 500, 750, and 1000 mg/kg, the percentage of insect-damaged kernels (IDK) was also greater in 3/4 resistant varieties than in the susceptible varieties. Results show combining the use of DE with varietal resistance of rough rice to R. dominica could be used to limit populations of this insect in stored rice and help prevent economic damage.