Host plant specificity in several species of generalist mite predators

1. Species in the genus Neoseiulus are considered to be generalist predator s. with some species used in biological control programmes against phytopha gous mites and insects. 2. A general survey of Neoseiulus species in inland Australia indicated tha t different species are associated with particular tree species. This patte rn of host plant use was investigated for four Neoseiulus species (N. buxeu s, N. cappari, N. brigarinus, N. eremitus) by means of a sampling programme through time and across space. 3. Each species of Neoseiulus was collected entirely or mostly from one spe cies of tree: little or no overlap was detected despite the tree species gr owing in well-mixed stands. Host plant specificity thus appears to be stron g in this genus. 4. Species in two other genera (Pholaseius and Australiseiulus), also consi dered to be predatory, showed a similar association with particular tree sp ecies. 5. The implications for the use of these predators in biological control ar e considerable. In particular, phytoseiid species with specific needs in te rms of host plants may not be suitable for use as general purpose predators . Meeting the needs of phytoseiids through the modification of host plant a ttributes may be a step towards enhancing their efficacy as biological cont rol agents.