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Title: FIELD AND LABORATORY BIOLOGY OF THE STEM-FEEDING BEETLE THAMNURGUS EUPHORBIAE (KOSTER) (COLEOPTERA: SCOLYTIDAE) IN ITALY, A POTENTIAL BIOLOGICAL CONTROL CANDIDATE OF LEAFY SPURGE IN THE USA AND CANADA

Author
item CAMPOBASSO, GAETANO - USDA-ARS-EBCL
item TERRAGITTI, GIANNI - USDA-ARS-EBCL
item Mann, Kimberly - Kim
item Quimby Jr, Paul

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2003
Publication Date: 5/26/2003
Citation: CAMPOBASSO, G., TERRAGITTI, G., MANN, K.D., QUIMBY JR, P.C. FIELD AND LABORATORY BIOLOGY OF THE STEM-FEEDING BEETLE THAMNURGUS EUPHORBIAE (KOSTER) (COLEOPTERA: SCOLYTIDAE) IN ITALY, A POTENTIAL BIOLOGICAL CONTROL CANDIDATE OF LEAFY SPURGE IN THE USA AND CANADA. JOURNAL OF APPLIED ENTOMOLOGY. 2003.

Interpretive Summary: Leafy spurge is a serious weed in the United States. Economic losses in U.S. caused by leafy spurge were estimated to be over $ 100 million per year. Leafy spurge covers pastures, prairies, and non crops areas in North America reducing forage production and displacing Native plants. Latex produced by the plants is an irritant and causes dermatitis to man and animals. Cattle generally avoid grazing it. This weed is used as forage only by sheep and goats, apparently without any deleterious internal effects. Thamnurgus euphorbiae is a beetle whose larvae feed in the stems of leafy spurge causing reduction in the height of the plant. Studies on the biology and host specificity showed that its host range is restricted to the leafy spurges. The beetle has been introduced into U.S. quarantine for additional host range testing. This report on the biology of the beetle provides workers with information on the insect's behaviour so it can be manipulated to its maximum potential in the biological control of leafy spurge in the United States.

Technical Abstract: The biology of Thamnurgus euphorbiae (Kuster) Coleoptera: Scolytidae was studied in the field and laboratory at the USDA-ARS-EBCL, Rome Italy. The Species is univoltine and overwinters as adult in the stems of its host plant, Euphorbia characias. Eggs are laid into stems of E. characias during April until early June. Larvae feed for about three months in the stem causing reduction of storage capacity affecting the whole plant. In the field, females mated at the end of March continuing first part of April. In the Laboratory the pre-oviposition period lasted 12.4 +/- 2.3 days and the average number of eggs per female was 75. The mean incubation period was 6.5 +/- 0.8 days; the pupal stage lasted 8.2 +/- 0.8 days; and females lived 104.1 +/- 7.8 days while males lived 34.5 +/- 5.3 days.