Introduced basswood thrips

Thrips calcaratus Uzel (Thysanoptera: Thripidae)

Orientation to pest

Introduced basswood thrips, Thrips calcaratus Uzel, is a European species invasive in eastern North America. Basswood thrips have rasping/sucking mouthparts and in early spring feed on buds, especially of American basswood (Tilia americana L.). Such bud-feeding causes mature leaves to be deformed or tattered and defoliation may occur. Repeated defoliation of American basswood reduces tree growth and increases rates of dieback from other causes. The species is of importance in northern Wisconsin, where outbreaks of damage occur.

Hosts commonly attacked

In North America, this species feeds on American basswood (T. americana).

Distribution

The species is found in New England and Quebec, westward through Ontario, Pennsylvania, New York and the Great Lake States.

Images of introduced basswood thrips

Kenneth Raffa, University of Wisconsin, Bugwood.org 768x512 / 1536x1024	Kenneth Raffa, University of Wisconsin, Bugwood.org 768x512 / 1536x1024	Steven Katovich, USDA Forest Service, Bugwood.org 768x512 / 1536x1024	Steven Katovich, USDA Forest Service, Bugwood.org 768x512 / 1536x1024
Figure 1. Adult of introduced basswood thrips, Thrips calcaratus	Figure 2. Larva of introduced basswood thrips	Figure 3. Typical damage to basswood buds from thrips feeding (here by another thrips, Neohydratothrips tiliae	Figure 4. Defoliation of American basswood by introduced basswood thrips

Important biological control agents related to this pest species

No specialized natural enemies of this thrips are known.

Web links for information on introduced basswood thrips

• "How to" Identification Publication | USDA Forest Service, Northeastern Area

Articles

• Raffa, K. F. and D. J. Hall. 1988. Thrips calcaratus Uzel (Thysanoptera: Thripidae), a new pest of basswood trees in the Great Lakes region. Canadian Journal of Forest Research 19: 1662-1663.
• Raffa, K. F. 1991. Biology and impact of Thrips calcaratus Uzel in the Great Lakes region, pp. 317-324. In: Parker, B. L., M. Skinner, and T. Lewis (eds.). Towards Understanding Thysanoptera. USDA Forest Service General Technical Report NE-147.
• Werner, S. M., M. A. Albers, T. Cryderman, D. Diminic, R. Heyd, R., B. Hrasovic, S. Kobro, S. Larsson, R. Mech, P. Niemela, M. Rousi, K. F. Raffa, K. Scanlon, and S. Weber. 2006. Is the outbreak status of Thrips calcaratus Uzel in North America due to altered host relationships? Forest Ecology and Management 225: 200-206.