PERMFILE40895 - Laserfiche WebLink

Home Browse Search

COLORADO DEPARTMENT OF AGRICULTURE BIOLOGICAL WEED CONTROL PROGRAM ABOIIr THE PROGRAM The Division of PIaM Industrys Biologipl Pest Control Section has ongoing biologipl control programs for thirteen noxious or problem weed spades. A total of 29 species of weed predators are being cultured, released, and established on weed infestations throughout the State. In addition to the biologicel weed control programs, this section conducts wntrol programs for the alfalfa weevil, pea aphid, Orier~l fruit moth, greenbug and Russian wheat aphid with a total of twelve benefidals. The primary function of the Biologicel Pest Control Section is the rearing and releasing of nature) enemies for control of specific plant and insect pests. This sec6an also ads as the State's receiving station for bielogicel control agents. Nex biological control programs are continualty being developed pdmarity by agendas of the United States Departrmertt of Agriculture. Foreign exploration produces several new species each year that are Imown to control introduced plant and insect pesLt These exotic spades are exposed to a strict quararrtine procedure before they became available to cooperating states for general release. This insures that pdentially hazardous spades are nd acddentally introduced with the benefidal insects. ABOl1T THE NATURAL ENEMIES LEAFY SPURGE (Euohorbia esula In 1989, two leafy spurge predators, tdhona flava and hthona nigriscutis, were obtained from collections in Canada and Europe. The adults of these flea beetles defoliate the spurge plants while the larvae feed on the roots. In 1991, a third flea beetle spades, hthona cvparissiae. was obtained from Canada and released. In 1992, a long-homed beetle, Oberea ervthrocephala, was obtained and released. The adults of the beetle feed on the wveground parts of the plant while the larvae bore into the stem and root crawrt. In 1993, a fourth flea beetle, hthona ¢walinae/lacertosa was obtained and released in the state. The larvae of A ¢walinaellacertosa feed an the roots and the adults feed on the leaves of leafy spurge. A gall forming midge, Sourgia esJlae was also released. This fly lays its eggs on the shoot tips of leafy spurge, and the larvae feed on the meristematic tips causing the plant to forth a gall around them. A final flea beetle species, hthona abdominalis was released in 1996. This is the smallest of the flea beetles and rouses similar damage to the plants as the other Aphthona spades. hthona nigriscutis. A wpadssiae and A ¢walinae/lacertosa have all become established at field insectary sites and ran be collected in large numbers. These benefidal organisms are now available for redistribution in the state and can be obtained by requesting releases through the Department of Agriculture. DIFFUSE AND SPOTTED KNAPVYEED (Centaurea difhrsa and C, maculosal The Colorado Department of Agriculture initiated a biological control program for spotted and diffuse knapweed in 1989 with the release of Uroohoro gall flies. ' lrophora affinis and guadrifasdata: These knapweed seed head 311 flies attack the flowers of diffuse and spatted Imapweed to produce galls and reduce seed production in infested plants. Bath spades are now well established in several locations in Colorado and can be collected for redisttibrrdon. Agapeta zo ana: This root boring moth was first acquired by Colorado in 1991 for field release. The larvae of this knapweed predator teed on the roots of spotted knapweed redudng the vigor. of the plant tt is presentty available for release on a limited basis. Metmeria paudpundella: In 1992, the Insectary received this flower-feeding gelechid moth. Surveys have recovered Metmeda from one of two 1992 release sites. tt has not reached populations that are large enough to allow for redistribution Sohenopteratuyoslavica: Received and released in 1991, this buprestid beetle attacks diffuse knapweed. The larvae bore into the root sawn and upper roots retarding the development of rosettes and stunting plant growth. This very effective benefidal organism has become established at a field insectary site and can be collected for use in a limited redistribution program. Cyphodeonus achates: This predator is a large root~oring weevil received for rearing in 1992 Rearing attempts in a garden rearing plot have been successful enough to produce C. achates in numbers that allow for releases into the field. They can be acquired upon request Banqastemus fausti: This small seedhead weevil was released in Colorado for the first time in 1993. Adults lay eggs on the flowers of diffuse and possibly spotted knapweed. The larvae feed within the flower receptade, destroying the seed. Recovery of this insect has not occured and redistribution will be unlikely. Carious minutus: Initial releases of this seedhead weevil occurted in 1995. Prefering diffuse knapweed, the larvae of this spades feeds on the seeds of the plant redudng seeding potential. Post- release surveys for this insect have revealed establishment and overwintedng, but population numbers are nd large enough to allow for collection for redistribution. Carious obtusus: Larvae of this spades prefers spotted knapweed and consumes the majority of seeds. Introduced in 1996, this spades has not been recovered in Colorado. RUSSIAN THISTLE Salsola iberica Control agents to reduce this weed population consist of two predators, Coleoohora klimeschiella a foliage feeding pse bearing moth, and C. parthenica a stem boring moth. Both of these spades minim¢e the spread of Russian thistle by redudng seed potential and are established in Colorado. They are available for release upon request