Submitted to: Journal of Entomological Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/4/2007
Publication Date: 8/7/2008
Citation: Leskey, T.C. 2008. Reproductive development of female plum curculio, conotrachelus nenuphar (Herbst) in the mid-atlantic: Presence of multivoltine populations. Journal of Entomological Science. 43(2):208-216. Interpretive Summary: The plum curculio is one of the most serious pests of apple and peach orchards in the mid-Atlantic. One of the critical questions for growers in this region is whether the summer generation is capable of reproduction and therefore of damaging fruit. In the northeastern states, the summer generation is incapable of egg-laying prior to overwintering, whereas in the southeast, populations are capable of reproduction throughout the summer months until harvest. Based on dissections of trapped females in the mid-Atlantic, plum curculio in this region are capable of reproduction and pose a threat to growing fruit from the time fruit has set until harvest.
Technical Abstract: The plum curculio, Conotrachelus nenuphar (Herbst), is a key pest of pome and stone fruit throughout eastern and central North America. There are two strains of plum curculio, the univoltine ‘northern’ strain and the multivoltine ‘southern’ strain. Voltinism associated with populations located in the mid-Atlantic region has been unclear with historic records indicating the presence of univoltine populations, but recent studies suggesting multivoltine populations. Female plum curculios obtained from emergence and screen traps and from samples of host tree canopies strongly point to the presence of multivoltine populations, based on an ovarian development bioassay. Two periods of active oogenesis were detected. The first occurred in early spring between late April and early May, and represented overwintered females who were becoming sexually mature. A second period of oogenesis was detected beginning in late June and continuing through early August. Based on degree day accumulations and known developmental rates of plum curculio, the mid-Atlantic is comprised, at least in part, of multivoltine populations. Fruit growers, therefore, must consider that plum curculio can pose a threat to tree fruit throughout the active growing season.