LAUSR

Simple Summary To improve the control of stored-grain pests and protect the environment, the use of natural enemies is attracting increasing attention. Cheyletus malaccensis and Cheyletus eruditus are effective natural enemies of common stored-grain pests, such as Liposcelis bostrychophila Badonnel. To evaluate the predation potential of these two types of predatory mites, this study was conducted by comparing the life histories of two predatory mites and the functional responses on Liposcelis bostrychophila. The results indicate that compared to C. eruditus, C. malaccensis had a shorter development time and longer adult survival time at 28 °C and 75% RH and showed higher predation ability against Liposcelis bostrychophila eggs. It has been proven from both its life history of artificial breeding and the predation ability that C. malaccensis has much greater biocontrol potential than C. eruditus against stored-grain pests. Abstract Cheyletus malaccensis Oudemans and Cheyletus eruditus (Schrank) are predators of stored-grain pests in China. The psocid Liposcelis bostrychophila Badonnel is prone to outbreaks in depots. To assess the potential of large-scale breeding with Acarus siro Linnaeus and the biological control potential of C. malaccensis and C. eruditus against L. bostrychophila, we determined the development times of different stages at 16, 20, 24, and 28 °C and 75% relative humidity (RH) while feeding on A. siro, as well as the functional responses of both species’ protonymphs and females to L. bostrychophila eggs at 28 °C and 75% RH. Cheyletus malaccensis had a shorter development time and longer adult survival time than C. eruditus at 28 °C and 75% RH and could establish populations faster than C. eruditus while preying on A. siro. The protonymphs of both species showed a type II functional response, while the females showed a type III functional response. Cheyletus malaccensis showed a higher predation ability than C. eruditus, and the females of both species had a higher predation ability than the protonymphs. Based on the observed development times, adult survival times, and predation efficiency, Cheyletus malaccensis has much greater biocontrol potential than C. eruditus.