The parasitoid complex of the citrus psyllaTrioza erytreae (Del Guercio) [Homoptera: Psyllidae

Abstract

Associated with the citrus psylla,Trioza erytreae (Del Guercio), in Salisbury, Rhodesia, are two primary parasitoids and 13 secondary and tertiary hyperparasitoids. One of the primary parasitoidsTetrastichus? radiatus remains external to the psyllid host whereas the other primary,Psyllaephagus pulvinatus, is an internal parasitoid. The major secondary hyperparasitoidAphidencyrtus cassatus, which was recorded in large numbers, attacks both primary parasitoids. Accounts are given of the biology of the two primary parasitoids and ofA. cassatus. The other hyperparasites in the complex are numerically unimportant and summaries of their biology are contained in a table. A diagram is given to illustrate the interrelationships of the parasitoids in the citrus psylla complex. It is concluded that, apart from phenological effects on the insects and host plant, the two primary parasitoids have considerable impact in controlling numbers of their host,T. erytreae, and that the secondary parasitoidA. cassatus through its attacks on the primary parasitoids is also of major importance in determining population levels achieved by the citrus psylla. Some characteristics of the parasitoids in the complex are discussed which might explain the high population levels of citrus psylla achieved in the Salisbury area. Several research avenues exist which would clarify the feasibility of biological control procedures againstT. erytreae.