Russian knapweed biological control success with host specific wasps and midges
By Sonya Daly, Dan Bean and Melanie Mollack of the Colorado Department of Agriculture, Conservation Services, Biological Control Program. Russian knapweed (Rhaponticum repens) is a nonnative weed in the western United States. It was introduced in the late 1800’s and is now invading and degrading cropland, rangeland, riparian areas, and roadsides.
Invasive weeds in America’s Western states: restoring balance using biological control
In many of America’s Western states, invasive weeds such as houndstongue (Cynoglossum officinale), Russian knapweed (Rhaponticum repens), yellow and Dalmatian toadflax (Linaria vulgaris and Linaria dalmatica), oxeye daisy (Leucanthemum vulgare), and hoary cress (Lepidium draba) are serious problems. However, research shows that biological control, as part of an integrated weed management strategy, offers the potential for a cost effective and efficient way of reducing invasive plant species to levels below acceptable damage thresholds.