Evaluation of green lacewings, Chrysoperla plorabunda (Fitch) (Neurop., Chrysopidae), for augmentative release against Toxoptera citricida (Hom, Aphididae) in citrus

Larvae of the lacewing Chrysoperla plorabunda (Fitch) were evaluated in lab oratory and field tests for potential to control the brown citrus aphid, To xoptera citricida (Kirkaldy) in inundative releases. Larvae surviving to pu pation consumed an average of 1676, 1297, 392, 165 and 130 1st-4th instar T . citricida nymphs and apterous adults, respectively, and the mean developm ental time was 27.0, 23.0, 16.5, 13.8 and 18.3 days, respectively. The aver age pupation rate was 37.5%, but only 6.3% of pupae yielded adults. Develop mental time and survival to pupation varied with the life stage of aphids f ed to larvae, 4th instars yielding the highest survival and shortest develo pmental time. Development of C. plorabunda was compared on diets of T. citr icida and Aphis spiraecola. Only 6.3% of larvae completed development on T. citricida, whereas 37.5% yielded adults on A. spiraecola. Larvae consumed more of the brown T. citricida than the green A. spiraecola in a choice tes t on a white background, but no preference was evident when aphids were off ered on a black background. Two separate field trials were performed in cit rus groves with T. citricida infestations in which an average of 275 and 11 6 C. plorabunda larvae/tree were released, respectively. The rate of T. cit ricida colony maturation ( = survival to alate production) was very low in the first trial, and relatively high in the second trial, but did not diffe r between control and release trees in either trial. The most apparent caus e of aphid colony mortality was predation by the coccinellids Cycloneda san guinea L. and Harmonia axyridis Pallas. Despite acceptance of T. citricida in the laboratory, very few C. plorabunda larvae were observed feeding on a phid colonies on release trees.