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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #101106
Title: DISTRIBUTION AND SEASONAL BIOLOGY OF THE RECENTLY INTRODUCED WEEVIL, ISCHNOPTERAPION VIRENS (HERBST) IN THE NORTHEAST

Author
item Byers, Robert
item STIMMEL, J - PA DEPT. OF AGRICULTURE

Submitted to: Northeast Regional Field Crops Insect Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/24/1999
Publication Date: N/A
Citation: Byers, R.A., Stimmel, J.F. 1999. Distribution and seasonal biology of the recently introduced weevil, ischnopterapion virens (herbst) in the northeast. Northeast Regional Field Crops Insect Conference Proceedings. p. 10-13.

Interpretive Summary:

Technical Abstract: The apionid weevil, Ischnopterapion virens (Herbst), a pest of clover in Europe, was first detected in the U.S. in pitfall trap collections from two dairy farms in Berks County, PA, by R.A. Byers and G.M. Barker in 1994. Adults were collected from 22 counties in eastern PA. Additional collections were made by cooperators in three New Jersey counties in 1997, 5 New York counties in 1997 and 1998 and in New Castle County, DE, in 1998 The highest numbers of the weekly abundance of adults collected during the year on a dairy farm occurred in the first sample taken on April 7, 1998. There was a slight decline in numbers collected in late spring and an increase in June. The adults disappeared in summer and were again numerous in late fall and winter. Adults eat small holes in leaflets. The number of holes in leaflets paralleled the abundance of adults with greatest number of holes occurring when adults were most abundant. Interior of some estolens of white clover were tunneled by larvae in May. Pupation occurred in late May and exit holes made by the emerging adults appeared the first week of June. Adults preferred white and red clover over the alfalfa, black medic, and birdsfoot trefoil in the laboratory. No weevils were found on alfalfa in the field. There were never any holes in alfalfa leaflets in the same paddocks that had white clover with holes. On the other hand, red and white clover leaves frequently had holes in the field. It is not known whether feeding by I. virens will be economically important in pastures. The feeding by the adults causes minimal damage to leaflets and probably is not important to restricting plant growth. Most of the damage to clover is done by larvae. Red clover seems to show greater damage than white clover.