COMPETITION BETWEEN PSYLLAEPHAGUS-YASEENI AND TAMARIXIA-LEUCAENAE, 2 PARASITOIDS OF THE LEUCAENA PSYLLID (HETEROPSYLLA-CUBANA)

Laboratory experiments were carried out on populations of the leucaena psyllid (Heteropsylla cubana Psyllidae) and two parasitoids, Psyllaep hagus yaseeni (Encyrtidae) and Tamarixia leucaenae (Eulophidae) to det ermine to what extent the parasitoids compete. When both parasitoids w ere introduced to caged populations of the psyllid, fewer mummies were produced than when equivalent numbers of P. yaseeni alone were introd uced. Multiparasitism was confirmed by dissection. The extent of multi parasitism was found to be dependent on the number of unparasitized ps yllid nymphs available to T. leucaenae. Behavioural observations indic ated that T. leucaenae tends to avoid searching and ovipositing on pla nts previously exposed to P. yaseeni. Superparasitism occurs in P. yas eeni but the distribution of attacks suggests that females discriminat e between parasitized and unparasitized hosts and avoid ovipositing in the former. Superparasitism by T. leucaenae is very rare and was not recorded in this study.