Potential of Acarophenax lacunatus (Prostigmata: Acarophenacidae) as a biological control agent of Rhyzopertha dominica (Coleoptera: Bostrichidae)

A recent report of the parasitic mite species Acarophenax lacunatus (Cross and Krantz) (Prostigmata: Acarophenacidae) attacking populations of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) led to the present investigation. Maximum female size and average number of progeny per female mite were assessed at eight different temperatures (ranging from 20 to 41 degrees C) and 60% r.h. using R. dominica as the host. The ability of the mite species to suppress eggs, first instar larvae, and adults of R. dominica was assessed at 30 degrees C and 60% r.h. The largest female sizes of the mite and progeny numbers were obtained around 30 degrees C (259 mu m and 17 offspring/female respectively) with minimum values obtained at the most extreme temperatures used in this study. Mite densities of at least four individuals per 500 mi jar containing 50 adults of R. dominica, resulted in almost complete suppression of eggs, first instar larvae, and adults of the host species after 45 days. This same range of mite densities led to reductions of wheat weight losses of 15 and 25% after 45 and 60 days after infestation respectively. Acarophenax lacunatus shows good potential as a biological control agent of R. dominica. (C) 2000 Elsevier Science Ltd. All rights reserved.