The predator fauna on windbreaks composed of longleaf podocarpe (Podocarpus macrophyllus D. DON.) and sugi (Cryptomeria japonica (L. fil.) D. DON.) around satsuma mandarine (Citrus sulcata hort. ex TANAKA) groves was investigated at Akitsu, Hiroshima Prefecture over a six year period from 1978 to 1983. The fauna of predaceous mites was also studied on various windbreaks around the citrus groves in western Japan. In longleaf podocarpe, eight species of Coccinellidae; Coccinella septempunctata LINNAEUS, Harmonia axyridis (PALLAS), Propylea japonica (THUNBERG), Scymnus posticalis SICARD, Menochilus sexmaculatus (FABRICIUS), Hyperaspis japonica (CROTCH), Telsimia nigra (WEISE), Chilocorus kuwanae SILVESTRI, and Cybocephalus nipponicus ENDRODY-YOUNGA, two species of Staphylinidae; Oligota kashmirica benefica NAOMI and O. yasumatsui KISTNER, Chrysopa sp., three species of Phytoseiidae; Amblyseius eharai AMITAI et SWIRSKI, A. longispinosus (EVANS), A. sp., Agistemus terminalis (QUAYLE), Anystis sp. and some spiders are found. In sugi, three species of Coccinellidae (T. nigra, C. kuwanae, and Stethorus japonicus H. KAMIYA) and two species of Phytoseiidae (A. longispinosus and A. sp.) were found, but the numbers of these species were fewer than those found in longleaf podocarpe. In other families, there was no difference between the windbreaks. The population density of A. terminalis in both trees was the highest with a ratio of 60-70% in total populations. The density of spiders was the next highest. In longleaf podocarpe, the ratio of population densities of A. eharai and A. longispinosus was about 5% in total populations. The ratio of Coccinellidae was about 3%. In sugi, the ratio of population densities of the two species of Staphylinidae was 6%. The fauna of predaceous mites on various windbreaks was different among different species of trees. Variance of predaceous mites was especially high on longleaf podocarpe, A. eharai and A. terminalis were the dominant species.
