As they mature they will consume most of the seeds, thus reducing the reproduction potential of the plant. Over a period of time, the reduction of seed will result in the suppression of the knapweed infestations. The adult of this beetle lays its eggs near the base of the plant. The larvae feed on roots and root hairs, causing extensive damage to the vigor of the plant. In some areas, large infestations of leafy spurge have been suppressed by the damage caused by these insects.
Adults feed extensively on the plant when they emerge in the spring.
The larvae feed in the crown of the plant at the soil line, which results in the inability of the plant to bolt and produce viable seed. This insect has been responsible for the reduction of the spread and density of musk thistle in parts of the State. Personnel from the Biological Pest Control Section will soon be going to the field to collect these natural enemies from previously established insectary sites. The collections will be brought back to the laboratory and individual species will be sorted, counted and packaged for release. The number of insects that are available for release will limit the number of requests that can be filled.