A Survey of Parasitoids of Brown Citrus Aphid (Homoptera: Aphididae) in Puerto Rico

The brown citrus aphidToxoptera citricida(Kirkaldy) (Homoptera: Aphididae) is a pest of citrus and an efficient vector of citrus tristeza virus. Reproducing populations of this aphid were first detected in Puerto Rico in April 1992. In 1994, we surveyed citrus in Puerto Rico for the aphid and its parasitoids. The brown citrus aphid was the most abundant aphid on citrus and its populations were statistically higher in April than in July and December. Aphid populations in commercial and dooryard citrus were significantly higher than those in nurseries (P < 0.05).Lysiphlebus testaceipes(Cresson) (Hymenoptera: Aphidiidae) was the only primary parasitoid found attacking the aphid. The parasitism rate was only 3.6% overall and was somewhat greater in April at 5.9% and December at 7.0% than in July at 2.9%. Parasitism was higher in dooryard citrus than in commercial or nursery fields (P < 0.05). Primary parasitoid emergence rate from mummies was low at 4.0%, indicating that the brown citrus aphid was a marginal host or that conditions were not adequate. A low level of hyperparasitism byPachyneuronsp. was also observed. We conclude that the aphid was not under good biological control by parasitoids and suggest that classical biological control efforts should be undertaken.