ARS | Publication request: Methodology for determining susceptibility of rough rice to Rhyzopertha dominica (L.) and Sitotroga cerealella (Olivier)

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 26, 2013
Publication Date: N/A

Interpretive Summary: There are few recent test that evaluate susceptibility of stored rice to stored-product insects. We evaluated different long grain rice varieties for susceptibility to two major insect pests, the lesser grain borer and the Angoumois grain moth, using different methods. Adult lesser grain borers were first exposed on the rice varieties, then removed. Adult feeding caused the varieties to become more susceptible to larval feeding, which in turn increased progeny production. Some varieties were more susceptible than others to the lesser grain borer. Since adult Angoumois grain moths do not feed, we exposed mating pairs of adults to produce larvae that would infest the rice. All varieties were susceptible to damage caused by larval Angoumois grain moth, including those that did not support lesser grain borer growth and development. Results show that varietal susceptibility to stored-product insects may differ with insect species.

Technical Abstract: Varieties of rough rice, Oryzae sativa (L)., were obtained from different sources in the south-central United States and evaluated for susceptibility to the lesser grain borer, Rhyzopertha dominica (Fab.), and the Angoumois grain moth, Sitotroga cerealella (Olivier), in laboratory studies. Adult R. dominica were fed on the rice varieties for 2 weeks, removed, and assessed for progeny production after an additional 6 weeks. S. cerealella susceptibility was evaluated by exposing two mating pairs of moths on a particular variety until the adults died. R. dominica parental survival, progeny production, and feeding damage by parental and progeny adults were variable, with survival ranging from 19.4% to 95%. R. dominica parental feeding damage, progeny production, and progeny feeding damage were all correlated (r = 0.35 to 0.97, P < 0.001). Parental feeding of R. dominica provided access for neonates to infest the rice hull. All rice varieties supported development of S. cerealella, and the variety Vista, which did not support growth of R. dominica, was one of the most susceptible varieties to S. cerealella. Progeny production of both species was generally correlated, but we observed only two instances of specific correlation for any rice variety.