ENY-847 Biology and Management of Aphids in Sustainable Field Production of Cucurbits 1 O. E. Liburd, T. W. Nyoike, and J. M. Razze 2 1. This document is ENY-847, one of a series of the Entomology and Nematology Department, UF/IFAS Extension. Original publication date January 2008. Revised December 2015. Visit the EDIS website at http://edis.ifas.ul.edu. 2. O. E. Liburd, professor, Agricultural Entomology; T. W. Nyoike; and J. M. Razze post-doctoral research associate, Entomology and Nematology Department; UF/IFAS Extension, Gainesville, FL 32611. The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or ailiations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension oice. U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. Aphids (Hemiptera: Aphididae) are minute pear-shaped, sot-bodied insects. heir high reproductive potential and ability to transmit viral diseases make aphids a signiicant pest of crops worldwide. here are approximately 4,400 aphid species in the world (Blackman and Eastop 1994). Several species can be found on cucurbits. hree species that can colonize members of the Cucurbitaceae family are the melon aphid, Aphis gossypii Glover; the green peach aphid, Myzus persicae (Sulzer); and the cowpea aphid, Aphis craccivora Koch (Zitter et al. 1996). Members of the Cucur- bitaceae family include watermelon, squash, and cucumber. Biology and Lifecycle In the spring, female nymphs hatch from the eggs on the primary host and feed to maturity. here are several variations of aphid life cycle. Aphids alternate primary hosts with secondary hosts, sexual with nonsexual (partho- genetic) reproduction, migrant with nonmigrant forms, and wingless with winged forms. Winged (alatae) forms migrate and feed on summer crops such as cucurbits. Females reproduce parthenogenetically, giving rise to live nymphs. Males and females are produced in the fall, and then migrate onto winter hosts where they mate to produce eggs. In the tropics and subtropics, female nymphs are produced all year round (Zitter et al. 1996). he bulk of aphid virus vectors belong to the genera Myzus (e.g. green peach aphid), Aphis (e.g melon aphid, cowpea aphid), Acyrthosiphon, and Macrosiphum (Katis et al. 2007). Some authors have referred to the melon aphid as the most damaging aphid species, but others have argued against this when they consider transmission of non-persistently transmitted viruses. Melon aphids are able to establish and colonize on the leaves as opposed to non-colonizing species, which are mobile and hence more eicient in virus transmission. Damage Aphids suck sap from plants and cause the leaves to appear curled and distorted, especially when the population is high. hey excrete honeydew, a sugar-rich substrate that promotes the growth of sooty mold (Capnodium spp.) on harvestable plant parts and leaves, lowering their quality. heir most distinct damage to cucurbits is their ability to transmit viruses in a non-persistent manner (Figure 1). his is a mode of transmission that is characterized with a short time of acquisition, inoculation (< 1 min), and retention with brief stylet penetration before the virus is passed onto another host (Nault 1997). hese viruses include Papaya ring spot virus-Watermelon strain (PRSV-W), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV) and Cucumber mosaic virus (CMV).