Mecinus janthiniformis
Insects, mites and pathogens released to suppress specific noxious weeds as part of an integrated weed management program.
Biology
Adult M. janthiniformis emerge from stems in May, and reproduce until late June. Adults are appx. 4 mm long. Eggs are laid in cavities inside the stem. Eggs hatch in 7 days. Larvae development takes 20-30 days. Larvae are 1-2 mm long, cream colored and C-shaped with brown head capsules. Pupation occurs in stems. Adults overwinter in stems.
Destructive Stage
Larvae (stem mining) and adult (feeding on foliage)
Impact To Host
Impact of weevils is most effective during drought years. Control is usually 60-75%, although several sites in Utah have collapsed after 6-7 years.
Redistribution
Adults can be collected in May and June using a sweep net and aspirator or by picking insects directly off of plants. A typical release is 250-500 weevils. Releases should be made in dense infestations of dalmatian toadflax.
