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TALL LARKSPUR (Delphinium oceidentalel The larkspur midd, H~o lomachus atfieuratvs is a true bug that reds on the stems, leaves and flower buds of tall larkspur. After being damaged by the insect, the plant is no longer grazed on by cattle. Collection for this natural enemy occurs in a field nursery sde located on the Flat Top Mountains above Riga. tt rs available for release upon request PUNCTUREVINE ribulusterrestris The most successful biological control agerds are Microlarinus lareynii. a seed feeding weevil, and Microlarinus nfonnis a stem !wring weevil. M. lareynii and M. dfonnis have been collected from established cobnies around the state. Redistribution of M. larevnii and M. dformis is available upon request As part of two benefidal insect exchange programs, these weevils were sent to Oregon and Washington State. MUSK THISTLE Carduus nutans The primary predator of musk thistle, Rhino lus conicus was first received and released by the Insectary in 1974. Musk thistle seed vree~I has proven very effective. The production of viable seeds is greatly reduced, thus slowing the spread of this vreed. Since the first release of R. conicus in 1974, the Departrnent has established seed weevil in musk thistle sites throughout Colorado. Musk thistle seed weevil has successfully colon¢ed thistle sites around the State and can be found established at all previous release locations. tt is readily available for release upon request ~ichosirocalus honidus attacks the crown of the thistle by killing me apical meristem and reduces the flowedne potential of the plant This benefidal insect is well established in many areas around the state and can be obtained upon request A third spades added to the complex of musk thistle predators is the Cassida rubiginosa. aleaf-feeding tortoise beetle that causes considerable damage to musk thistle plants by skeletomm~g the leaves. Because this beetle's feeding habit does not compete with R. cronicus or T. honidus C. rubiginosa should complement the other spades to give more complete corrtrol of musk thistle. It is limited in numbers and is not available for general release. TOADFLAX -Yellow and Dalmatian Linaria wlgaris and L genistifolia ssp. dalmatica) Calophasia lunula a predatory noduid moth, has been reared and released by the Colorado Departrnent of Agriatture for control of the toadflax spades. The C. lunula larvae feed extensively on leaves and flowers of toadilax, severely damaging the plants. tt has been recovered in Colorado and is available on a limited basis upon request Twv mare spades of predators have recently been received to be reared for release on the toadflaxes. Eteobalea intennediella a root bortng moth, and Mednus iarrthinus. a stem baring weevil, are cunendy in early stages of production. ''JLL THISTLE Cirsium vui are Urophora ata a fly predator, is used to help control this thistle. The female fly lays eggs in the seed head of the thistle. The maggot then consumes the seed in the flovrer. This spaces has ovenvintered in Colorado but the limited numbers will not allow for general redistribution. CANADA THISTLE Cirsium arvense Ceutorhvnchus IihJra a predator of Canada thistle, feeds on the plant externally as an adult, while the larvae mine the leaves and stems. In addition to feeding damage, the entrance and exit holes made by the larvae provide infection sites for diseases that stress the plant even further. This predator has been released in several locations in Colorado but has yet to became established making it unavailable for general release. A second predator, Uroohom p~dui has been released to help combat Canada thistle. This gall tonning fly has become established in Colorado and is available on a very limited basis upon request Cassida rubiginosa has also been released on Canada thistle. Recovery of this spades has not ocarmcd and it is not available for release at this time. RUSSIAN KNAPWEED (Centaurea re ns Shipments of the Russian knapweed loving nematode, Subaneuina ip aidis• have been received by the Biological Pest Control Section for the last several years. This nematode will stimulate gall Tortnation on the leaves and stems of the p1aM causing a general decline which may result in death. tt is a slowly dispersing organism that will require great patience before d can be spread to all knapweed infestations. It is now established in three locations in Western Colorado but is not available for general release. PURPLE LOOSESTRIFE L rum salicaria I-!`/iOh10.^.. Sr3nSVnrSpviNatl'S IL 9 large IOr:g~IV2d weGl,il '_hat hr„ps control purple Ioosestrife plants. The adults overwinter in the soil dose to the location of loosestrife plants. They are nocturnal and feed mainly on the leaves. The larvae do the most damage to the plant by feeding on the root cortex and then entering the root itself and packing the roots with light brown frass. This species is being reared at the Insectary and will be available for release when numbers increase. The Insectary also received a culture of Galerucella calmariensis and Gaieruceila up sjlla• which are foliage feeding beetles of purple loosestrife. These insects are being reared in the laboratory for general release. Galerucelia are voracious feeders and can wmpietely defoliate a plant, thus eliminating any seed production. K is available upon request Colorado Department of Agriculture LYvision of Plant Industry 700 /Gp6ng St., Sude 4000 (akeHrood, CO 80215 (303)239-4140 /nsectary Facility P.O. Box 400 Palisade, CO 81526 (970)464-7916 298