Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2005
Publication Date: 1/1/2006
Citation: Rector, B.G., Harizanova, V., Sforza, R., Widmer, T.L., Wiedenmann, R.N. 2006. PROSPECTS FOR BIOLOGICAL CONTROL OF TEASELS, DIPSACUS SPP., IN THE UNITED STATES. Biological Control. 1:1-14. Interpretive Summary: Common teasel (Dipsacus fullonum) and cutleaf teasel (D. laciniatus) are tall, spiny, invasive plants that have been increasing in importance as weeds in recent years in the U.S. These biennials of European origin have been declared noxious in five states and were recently designated as targets for biological control by the USDA-ARS National Program Staff. The main principal behind biological control of weeds is to identify natural enemies (e.g. insects or plant diseases) of the target plant in the target's native range. Often the target plants are not weed problems in their native habitat due to the feeding of their natural enemies. Once identified, the natural enemies are then tested to determine their host-range and impact. Natural enemies that are limited to feeding only on the target weed may be proposed for release as biological control agents in the weed's invaded range (in this case, the midwest and western states). Their feeding can help reduce the economic and ecological damage caused by the target weeds. This article describes the initial literature and field surveys undertaken to identify natural enemies of teasels in their native range. The authors conclude by recommending that certain of these natural enemies be given high priority for further study leading to possible release as biological control agents.
Technical Abstract: Two closely related teasels (Dipsacales: Dipsacaceae, Dipsacus spp.) of European origin have become invasive weeds in the United States. Common teasel (Dipsacus fullonum L.) and cut-leaf teasel (D. laciniatus L.) have likely been in North America for more than two centuries, having been introduced along with cultivated teasel [D. sativus (L.) Honckney], an antiquated crop plant. There are few records of American insects or pathogens attacking Dipsacus spp. Invasive teasels have recently begun to spread rapidly throughout much of their current range, for reasons that are not yet known. Common and/or cut-leaf teasel have been listed as noxious in five U.S. states and as invasive in twelve other states and four national parks. Current management practices for invasive teasels, especially mowing along highways, may actually be increasing invasive populations rather than controlling them. Because the family Dipsacaceae is an exclusively Old World family, classical biological control is considered to be an important component of the overall management strategy of this weed in the U.S., and represents one of the best long-term options for control of invasive teasels. Field surveys for natural enemies of D. fullonum and D. laciniatus in their native ranges and literature reviews of natural enemies of plants in the family Dipsacaceae have produced 114 species of insects in six orders, as well as 27 fungi from 10 orders, two mites, one nematode, and two viruses. Prioritization of these biological control candidate species for intensive study is discussed.