Functional responses of predatory mites, Cheyletus eruditus (Schrank) and Cheyletus malaccensis Oudemans (Trombidiformes: Cheyletidae) to Liposcelis decolor (Pearman) (Psocodea: Liposcelididae)

Psocids (Psocodea: Liposcelididae) are stored-product pests that are not easily managed by standard management tools and practices, such as insecticides. Biological control can be an effective alternative or complement to pesticides in the management of psocids in some scenarios. This study was carried out to evaluate the efficiency of two predatory mite species, Cheyletus eruditus (Schrank) and Cheyletus malaccensis Oudemans (Trombidiformes: Cheyletidae) to manage Liposcelis decolor (Pearman) (Psocodea: Liposcelididae), a key stored product psocid pest species that is phosphine tolerant. The functional responses of these two cheyletid mites to nymphs, adult males and females of L. decolor was determined under laboratory conditions at 24 ± 1 °C and 0: 24 (L: D) photoperiod. Based on the results of maximum likelihood estimates (MLE) of a logistic regression analysis, the functional responses of both the predatory mites to nymphs and adult males or females of L. decolor were Holling Type II. Subsequent estimations of attack rate (a), handling time (Th), maximum predation (K), and predation efficiency (η) per day (d) using a linearly transformed Hollings Type II model for predators against prey life stages revealed that C. eruditus performance was preferable compared to that of C. malaccensis. Similarly, the per capita consumption rate and searching efficiency of C. eruditus were considerably higher compared to C. malaccensis for all life stages of L. decolor. Nevertheless, further studies are required to validate the efficiency of C. eruditus and C. malaccensis based on other evaluation criteria including field trials, and their compatibility with other management strategies targeted at stored product pests in order to facilitate the incorporation of these mite species into existing IPM systems for managing psocids.