Powdery mildew (Ascomycotina: Erysiphales) - an alternative food for the predatory mite Typhlodromus pyri Scheuten (Acari: Phytoseiidae)

The ability of Typhlodromus pyri Scheuten to feed on powdery mildew was investigated. Adult females of T. pyri which had previously been fed on the pollen of Pinus sylvestris L. were offered three powdery mildew species and their feeding behaviour was observed. The females fed readily on the conidia of Erysiphe orontii Cast. from tobacco and Oidium fragariae Han. from strawberry while no feeding was observed on Erysiphe polygoni DC. from red clover, even after the mites were starved for 2 days. Erysiphe orontii was tested for its effect on the survival, oviposition and development of T. pyri. The results showed that the conidia of E. orontii can supply mites with the water and nutrients necessary for their normal development. Mature females successfully mated and reproduced, although their oviposition rate was low.