Some years back Barnes County, ND, had a release of Canada thistle stem gall fly, Urophora cardui, in the west central part of the county. Nothing showed up a first but now it appears the fly has established a population. The larva forms a gall on the thistle stem inhibiting seed production.
See: http://www.whitman.wsu.edu/weeds/canadathistle.html
While it's not the answer to control of these noxious weeds, every little bit helps. So when hunting, if you see a patch of thistles with the galls, pick a pocketfull and drop them off in another area with thistles. Farmers would appreciate it.
See: http://www.whitman.wsu.edu/weeds/canadathistle.html
While it's not the answer to control of these noxious weeds, every little bit helps. So when hunting, if you see a patch of thistles with the galls, pick a pocketfull and drop them off in another area with thistles. Farmers would appreciate it.