Submitted to: Weed Science Society of California Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 15, 2002
Publication Date: December 1, 2002
Citation: Smith, L. 2002. New developments in the biological control of invasive weeds. Weed Science Society of California Meeting Proceedings.` 54:159-165 Interpretive Summary: Biological control is an important tool to help manage invasive alien weeds. Biological control has provided environmentally benign, economical, self-perpetuating control of weeds that once infested large areas of the western U.S. Successfully controlled weeds include: St. Johnswort, tansy ragwort, puncture vine and musk thistle. However, research activity on biological control of weeds that are important in California decreased during the 1980s and 90s. This trend has recently changed. Over the past four years, the number of scientists working on biological control of weeds at the USDA Agricultural Research Service laboratory in Albany, CA, has increased from 1 to 6. The ARS European biological Control Laboratory in Montpellier, France, is now occupying a new building and has a new entomologist and a plant pathologist working on weed targets. Scientists in other state, federal and foreign institutions are also involved in research on an increasing number of target weeds. This paper presents a brief update on activities and accomplishments of projects targeting 24 species of weeds.
Technical Abstract: Six insects attacking yellow starthistle are widespread in California's central valley but have not substantially reduced weed populations. The accidentally introduced, false peacock fly is now widespread, but appears to pose no risk to native Cirsium thistles and negligible risk to safflower production. Insects have been recently released in California for salt cedar, purple loosestrife and squarrose knapweed. Petitions to release the yellow starthistle rust pathogen (Puccinia jaceae) and the rush skeletonweed root moth (Bradyrrhoa gilveolella) have been approved by the Technical Advisory Group (TAG), and APHIS approval is pending. Petitions have been recently submitted to TAG for new agents on salt cedar and Russian knapweed. Potential new agents are being tested for yellow starthistle, salt cedar, Russian knapweed, Cape ivy, French broom, Russian thistle, Scotch thistle, rush skeletonweed, and hoary cress. Foreign exploration projects have been initiated to find prospective agents for giant reed, perennial pepperweed, teasel and medusahead. Projects on houndstongue and sulfur cinquefoil have recently been suspended because of delays in receiving feedback from the U.S. Fish and Wildlife Service on the acceptability of proposed agents.