Knapweed Weed Control from Integrated Weed Control




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Knapweed

Good news for people concerned about spotted and diffuse knapweeds! The results of the knapweed biological control program are now evident. We are seeing stunning declines in plant density and vigor where insects have been established for several years. The best results are where the seed-head weevils (Larinus spp.) and the two root feeders (Cyphocleonus achates, Agapeta zoegana) are present.

Knapweed flower weevil

Larinus minutus/obtusus: These weevils are doing a great job in the field. They attack diffuse and spotted knapweeds. Larvae consume developing seeds. Adults feed on foliage and flowers.
$100 per release.

Spotted knapweed seed head moth

Metzneria paucipunctella: Adult moths lay eggs on bracts at the base of flowers. Larvae enter the flower, consuming florets and, later, seeds. Mature larvae mine the receptacle tissue. Metzneria does not do well in areas that are very cold with little snow cover.
$90 per release.

Spotted knapweed seed head moth

Metzneria paucipunctella: Adult moths lay eggs on bracts at the base of flowers. Larvae enter the flower, consuming florets and, later, seeds. Mature larvae mine the receptacle tissue. Studies have shown that this moth, together with the seed-head flies, reduces seed production more than either species alone. Metzneria does not do well in areas that are very cold with little snow cover.
$90 per release.

Sulphur knapweed moth

Sphenoptera jugoslavica : bronze knapweed root borer. This insect attacks the roots of diffuse (preferred) and spotted knapweed. surviving plants are stunted and produce fewer flowers. Often causes impressive population crash of diffuse knapweed.
$100 per release.

Knapweed root boring weevil

Cyphocleonus achates: This relatively new insect is very large and hardy. These weevils do a great deal of damage to roots and often kill attacked plants. This species is one of the most promising for knapweed control.
$120 per release.

Integrated Weed Control
4027 Bridger Canyon Road
Bozeman, MT 59715-8433

Toll Free: 1- 888-319-1632
FAX: 1-406-587-1989
E-mail: iwc@integratedweedcontrol.com

Problem Weeds

Leafy Spurge || Knapweeds || Canada Thistle
Musk Thistle || Yellow Starthistle
Poison Hemlock || Yellow and Dalmatian Toadflax
Saint Johnswort || Common Mullein
Purple Loosestrife || Rush Skeletonweed

Photographs courtesy of Integrated Weed Control, USDA ARS, APHIS Bozeman Bio-control Station, and Agriculture Canada.