Parasitization of Liriomyza spp. (Diptera: Agromyzidae) infesting commercial watermelon plantings in Hawaii.

Liriomyza sativae Blanchard and L. trifolii (Burgess) are the major insect pests attacking the foliage of watermelon grown on Oahu, Hawaii. Five spring and three summer commercial plantings of watermelon were surveyed in 1984 to identify major parasite species and level of parasitization of the Liriomyza complex. L. sativae was the predominant agromyzid species found in Kahuku, Oahu and composed > 70% of leafminers reared from watermelon. Overall, Chrysonotomyia punctiventris (Crawford) (45.2%) and Halticoptera circulus (Walker) (22.4%) were the predominant parasites reared from foliage collected in spring plantings. In summer plantings, importance of Ganaspidium hunteri (Crawford) (43.8%) increased and C. punctiventris (29.6%) decreased. Although insecticides were occasionally applied for secondary pests, the mean percentage of maximum leafminer parasitism was ca, 75.1%. However, pesticides were sometimes required for leaf miner control near harvest time.