Dalmatian and yellow toadflax are aesthetically pleasing weeds wreaking havoc in rangelands across the western United States. These non-native forbs spread rapidly into fields following fire, tilling, construction, or other disturbances. They are successful and stubborn invaders, producing massive quantities of seeds each year and rapidly re-sprouting from root fragments. Eight non-native toadflax feeding insect species have been intentionally released or accidentally introduced in North America.
Stem mining weevils, Mecinus spp., serve as particularly powerful "weed whackers" against toadflax. Biological control of toadflax is complicated by the existence of two Mecinus species - each of which performs better on different toadflax species - and the appearance of competitively superior hybrids of yellow and Dalmatian toadflax. Cooperation between researchers and managers continues to improve the effectiveness of biocontrol and make headway against weedy invaders.