Phytoseiid Mites (Acarina: Phytoseiidae)

This supplement accompanies volume 91 of the Memoirs of the Entomological Society of Canada.

Part 1. Bionimic of Seven Species in Southeastern England:
For 50 years mites of the family Phytoseiidae have been recognized as predators of phytophagous orchard-inhabiting mites, though our knowledge concerning them is slight. This paper is a study of phytoseiids in southeastern England. Phytoseiids are widely distributed in the study area. None exhibits plant-specificity, though they may show a preference for certain habitats. Each species overwinters as adult females, some on evergreen plants, others in bark crevices. Winter mortality is severe.

Though Typhlodromus pyri (Scheuten) is predacious on Panonychus ulmi (Koch) and other small acarines, plant food such as fungi and pollen is acceptable and allows both development and reproduction. These activities do not occur when only apple leaves are provided as food, though a small number of P. ulmi larvae initially eaten is sufficient to permit the phytoseiids to complete development with no other food than leaves. In the absence of plant material, approximately 25 P. ulmi larvae are required for development.

Insectary rearings estabhshed the developmental times of four common species. A field population of T. pyri Scheuten was studied in 1954 and 1955 and in 1955 several other species were also studied. Various aspects of the ecology of T. pyri were studied and related to those of its prey, P. ulmi, showing that the predator is inefficient and partially ineffective. These results were substantiated by field experimentation.

Part 2 is a taxonimic review of the family and describes 38 new species.