The bionomics of the South African citrus psylla Trioza erytreae (Del Guercio) (Homoptera: Psyllidae). 4. The influence of predators.

Abstract

Field studies in the eastern Transvaal and Swaziland citrus areas showed that Trioza erytreae is attacked by a complex of predators consisting of several green and brown lacewings, two syrphids, a coccinellid, and spiders and mites. Most of the insect predators were observed to feed also on the black citrus aphid which is sympatric with T. erytreae. Predators were found to be poorly synchronized with their psylla prey during early summer, when T. erytreae undergoes a rapid population rise, and at certain other periods of low or rising prey density. Together with several other limiting factors, predators clearly assist in suppressing populations of T. erytreae in midsummer and continue to be fairly active in autumn and early winter.