I stop what I’m doing for a moment and look up to watch a pair of circling Red-tailed Hawks. They’re smugly indifferent to my work, but their presence makes it go a little faster all the same. With the Western Meadowlarks, Lark Buntings, and Cassin’s Sparrows as a soundtrack, it’s a simply beautiful day to be outside.
Knapweed is a common pest on disturbed land, and as a perennial plant that can reproduce both by seed and creeping roots, it is a very successful invader. This sort of creeping perennial is very difficult to get rid of even with more active control methods, like herbicides. Biotic control is an alternative strategy that may increase effective weed suppression. Gall wasps lay their eggs inside the knapweed, forming stem galls on young knapweed plants, which slow the plant’s growth, diverting nutrients from flowers and seeds. Using gall wasps as biotic control, we aim to reduce the spread of knapweed and give native species a better opportunity to compete. Restoring disturbed land is a long-term endeavor, but it has to start somewhere, and gall wasps are just one piece of the puzzle in restoring Eastern Colorado rangelands.