Predators and Parasites of Insect Pests on Cantaloupe and Asparagus Bean, St. Croix, U.S. Virgin Islands R. G. Bland Biology Department Central Michigan University Mt. Pleasant, MI 48859 Cantaloupe (Cucumis melo L.) and asparagus beans (Vigna unguiculata subsp. sesquipedalis [L.] Verdc.), were sampled weekly for insect pests and their predators and parasites during the spring dry season. The three major pests of cantaloupe were melonworms (Diaphania hyalinata L.), melon aphids (Aphis gossypii Glover), and powdery mildew (Erysiphe sp.). Fire ants(Solenopsis geminata F.) became serious secondary pests by tending aphids. All four pests required chemical con- trol. Syrphid, chrysopid, and coccinellid larvae preyed on W. I. Knausenberger College of the Virgin Islands Agricultural Experiment Station P.O. Box 920, Kingshill St. Croix, U.S. Virgin Islands 00850 aphids but these predator populations were very low and developed too slowly to exert significant control. Two ichneumonid, one chalcid, and one tachinid species were reared from melonworm pupae and one of the ichneumonids, Agrypon caribbaeum Bland, occurred in sufficient frequency to consider its use as a biological control agent. Keywords: Aphis craccivora, Aphis gossypii, asparagus beans, cantaloupe, cowpea aphid, Diaphania hyalinata, Liriomyza sativae, melon aphid, melonworm, parasites, predators. Cowpea aphids (Aphis craccivora Koch) were the major pests on asparagus beans, but fair to good control was achieved on most plants from natural population increases of syrphid, chrysopid, and coccinellid larvae, and wasp parasites. Fire ants, leafhoppers (Empoasca sp.), and vegetable leafminers (Liriomyza sativae Blanchard), were secondary pests. Only 6% of the fruit and vegetables consumed in the U.S. Virgin Islands are grown locally (Mullins and Bohall, 1974). These. crops are produced in gardens for home use or in small commercial plots and sold at roadside stands or small, local grocery stores. The College of the Virgin Islands Agricultural Ex- periment Station and Cooperative Extension Service and the Virgin Islands Department of Agriculture continuously en- courage island residents to establish more and improved home gardens and small farms to decrease dependence on imported food, provide local income, and reduce food costs. St. Croix has more level and open terrain than the other two U.S. Virgin Islands and historically had been the center of the sugarcane industry. Eighty percent of this island is classified as subtropical, dry forest zone (Ewel and Whitmore, 1973). The re- maining 20% is a region of steep slopes in the northwest corner and is classified as a subtropical, moist forest zone. The dry forest zone is the major agricultural region. The average maximum and minimum temperatures are 30 annd 23C, ad the average an- nual rainfall near the experiment station is ca. 110 cm. However, irregular rainfall and high evapotranspiration typically cause a moisture deficit January through April so that crops are subject to periodic drought since ground and surface waters are not readily available for irrigation. Cantaloupe, Cucumis melo L., is a nutritious and popular food on St. Croix. The vines are able to tolerate fairly low moisture conditions although disease can be a major problem during the wet season. Different varieties of this crop have been tested for productivity at the St. Croix experiment station. Vigna unguiculata subsp. sesquipedalis (L.) Verdc., a subspecies of black-eyed peas (cowpeas or southern peas), is known as asparagus bean, Bodie bean, snake bean or yard-long bean. The 56 plant is grown in Southeast Asia and some areas of Africa and the West Indies (excluding the U.S. Virgin Islands) primarily for its immature pods which may attain a length of 1 m under optimum growing conditions (Purseglove, 1968). Asparagus beans are a climbing or bush-type annual, day-neutral, and tolerate heat and relatively dry conditions better than Phaseolu vulgaris L., the common bean. However, asparagus beans require a higher rain- fall than the drought-tolerant, common black-eyed peas (Purseglove, 1968). This research was conducted at the College of the Virgin Islands Agricultural Experiment Station (CVIAES), St. Croix. The objectives were to obtain data on insect pest, predator, and parasite populations on experimental plantings of cantaloupe and asparagus beans as the crops developed during the spring dry season. METHODS AND MATERIALS The Experiment Station soil is a Fredensborg clay loam, a highly calcareous, friable soil with a pH of 8 and 1.5 to 2.0% organic matter. It is very low in nitrogen, sulfur, and iron, and moderately low in phosphorous, copper, and manganese. Cantaloupe v. 'Top Mark,' was seeded January 18, 1982, in shallow lm2 depressions 2 m apart in 20 m rows. The six rows were spaced 2 m apart. Young plants were thinned to two per depression. Insect and other arthropod populations were monitored weekly on the entire plant surface and specimens were collected by hand for preservation or parasite rearing. Asparagus beans (Yates Co., New Zealand) were planted January 18, 1982, in shallow 0.1 m2 depressions spaced 0.6 m apart in rows with 1 m centers. Rows were kept weed-free and the climbing vines were tied to poles. All insects on a plant sample were counted weekly. A plant sample consisted of one trifoliate leaf (including the petiole) near the bottom, middle and top of a plant, and the length of the main stem. The first true leaf of a newly emerged seedling substituted for a trifoliate. During the first four weeks after seedling emergence 96 plants were sampled weekly and thereafter 24 plants formed a plant sample, the reduction in number due to the increased plant size. PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX