THE DIETARY-EFFECT OF WINDBREAK POLLENS ON LONGEVITY AND FECUNDITY OF A PREDACIOUS MITE EUSEIUS-ADDOENSIS-ADDOENSIS (ACARI, PHYTOSEIIDAE) FOUND IN CITRUS ORCHARDS IN SOUTH-AFRICA

The predacious mite Euseius addoensis addoensis (McMurtry) is an important predator of citrus thrips, Scirtothrips aurantii Faure, and Tetranychid mites on citrus in the eastern Cape Province of South Africa. It can also survive and reproduce on certain pollens. In this study, pollen collected from windbreaks commonly used around citrus orchards, was compared with that from Carpobrotus muirii (Mesembryanthemaceae) as a food source for predacious mites. Bioassays were conducted in the laboratory using a leaf-disk technique and both mite mortality and fecundity were recorded through one generation. Casuarina cunninghamiana (Casuarinaceae) was the only windbreak tested that produced pollen capable of sustaining E. a. addoensis for a generation with fecundity similar to that obtained with Carpobrotus muirii. Pollens collected from Pinus radiata (Pinaceae), Cupressus arizonica, C. goveniana and C. torulosa (Cupressaceae) were unsuitable. Casuarina spp. windbreaks may therefore help to maintain predacious mite populations during autumn when natural sources of prey are diminishing.