Vol. 109, No. 2, March & April, 1998 143 COCCINELLIDAE (COLEOPTERA) IN APPLE ORCHARDS OF EASTERN WEST VIRGINIA AND THE IMPACT OF INVASION BY HARMONIA AXYRIDIS 1 M. W. Brown, S. S. Miller 2 ABSTRACT: Twenty-five species of Coccinellidae were found on apple in eastern West Virginia from 1983 to 1996. From 1989 through 1994, the exotic coccinellid, Coccinella septempunctata (first collected in 1983), has dominated the fauna of the tribe Coccinellini. Another adventive species, Harmonia axyridis (first collected in 1994), became the dominant species in the tribe Coccinellini in 1995, and continues to dominate the coccinelline guild on apple. Harmonia axyridis has displaced C. septempunctata and is providing better biological control of Aphis spiraecola on apple in eastern West Virginia. Coccinellids (Coleoptera: Coccinellidae) are an important group of aphid predators in many ecosystems. Because of their ability to contribute to the control of pests, many coccinellids have been selected for introduction in bio-logical control programs. As of 1985, there had been 179 introductions of coccinellids into the U. S., with 26 species having become established; how-ever, 8 were a result of accidental introductions (Gordon 1985). Two recent coccinellid immigrants have made an obvious impact in the mid-Atlantic states. In 1973, Coccinella septempunctata L. was first found in New Jersey (Angalet et al. 1979), and it gradually spread throughout the Northeast (Schaefer et al. 1987). In 1988, H. axyridis was first found in Louisiana (Chapin and Brou 1991), and has since spread into the mid-Atlantic region (Day et al. 1994). Although both species had been released intentionally, their establishment ap-pears to be a result of accidental introductions (Day et al. 1994). Both species are now abundant throughout much of the northeastern United States and east-ern Canada (Hoebeke and Wheeler 1996) and have even become subjects of public concern because of occasional massive migrations of C. septempunctata (Schaefer et al. 1987) and by large numbers of H. axyridis overwintering in houses (Knodel and Hoebeke 1996). There have been numerous studies cataloguing the coccinellids in apple orchards in Europe and North America. In Europe, more than 23 species of coccinellids have been collected on apple, but usually 3 to 14 species in any one study (Hodek and Honek 1996). In a study spanning 4 years in 3 regions of Hungary, 23 coccinellid species were found on apple (Marko et al. 1 995). In Europe, Adalia bipunctata (L.) and C. septempunctata dominate in apple 1 Received July 7, 1997. Accepted September 6, 1997. 2 USDA, ARS, Appalachian Fruit Research Station, 45 Wiltshire Road, Keameysville, WV 25430. ENT. NEWS 109(2) 136-142, March & April, 1998
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