dc.contributor.author	Kuhar, Thomas P.	en
dc.contributor.committeechair	Youngman, Roger R.	en
dc.contributor.committeemember	Peterson, Paul R.	en
dc.contributor.committeemember	Mack, Timothy P.	en
dc.contributor.committeemember	Salom, Scott M.	en
dc.contributor.committeemember	Kok, Loke T.	en
dc.contributor.department	Entomology	en
dc.date.accessioned	2014-03-14T20:07:39Z	en
dc.date.adate	2000-02-22	en
dc.date.available	2014-03-14T20:07:39Z	en
dc.date.issued	2000-02-08	en
dc.date.rdate	2001-02-22	en
dc.date.sdate	2000-02-20	en
dc.description.abstract	The alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), remains a serious pest in Virginia despite being under complete biological control in the northeastern U.S. In 1996, a survey of 187 alfalfa fields in Virginia was initiated to determine the current pest status of alfalfa weevil and incidence of natural enemies. Fields located in the Piedmont region of the state had significantly higher alfalfa weevil pressure than those in the Shenandoah Valley and southwestern region. The dominant natural enemy of alfalfa weevil larvae was the parasitoid, Bathyplectes anurus (Thomson). Larval parasitization was lower in the Piedmont compared with the other regions. The entomopathogenic fungus, Zoophthora phytonomi, also killed weevil larvae in all regions. A more intensive ecological investigation of alfalfa weevil population dynamics and mortality was initiated in 1997 to determine why H. postica remains a pest in Virginia, particularly in the Piedmont region. Nine alfalfa weevil populations from three geographic locations were sampled and measured over a period of two years. Results showed that warmer winter temperatures in the Piedmont region contributed to a higher rate of alfalfa weevil oviposition compared with the Shenandoah Valley and southwestern mountains. Parasitization of adult weevils by Microctonus aethiopoides (Loan) was low in all regions of Virginia relative to rates reported in the northeastern U.S. This also contributes to relatively high alfalfa weevil fecundity in Virginia because a greater percentage of adults reproduce. Phenological asynchrony between M. aethiopoides and the alfalfa weevil may explain the low parasitism. The 1st generation of M. aethiopoides adults did not emerge until most of the overwintering alfalfa weevil adults had reproduced and died. A majority of alfalfa weevil eggs were laid before January at all locations in Virginia. Approximately half of the egg population survived to contribute to spring larval infestations. In the northern U.S., very few alfalfa weevil eggs survive the winter, and larval populations result primarily from spring-laid eggs. Mortality of larvae was high in Virginia and comparable to that reported in other states. Bathyplectes anurus was well-synchronized with alfalfa weevil and killed a high percentage of larvae.	en
dc.description.degree	Ph. D.	en
dc.identifier.other	etd-02202000-21040047	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-02202000-21040047/	en
dc.identifier.uri	http://hdl.handle.net/10919/26256	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	Chapter2.pdf	en
dc.relation.haspart	Chapter4.pdf	en
dc.relation.haspart	Chapter5.pdf	en
dc.relation.haspart	Chapter3.pdf	en
dc.relation.haspart	Chapter1.pdf	en
dc.relation.haspart	1frontmatter.pdf	en
dc.relation.haspart	Abstract.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	population ecology	en
dc.subject	biological control	en
dc.subject	pest management	en
dc.subject	alfalfa	en
dc.subject	Hypera postica	en
dc.subject	parasitoids	en
dc.title	Population dynamics, mortality factors, and pest status of alfalfa weevil in Virginia	en
dc.type	Dissertation	en
thesis.degree.discipline	Entomology	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

Population dynamics, mortality factors, and pest status of alfalfa weevil in Virginia

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