Noxious weeds can affect the quality of livestock pasture and cropland. Weeds and brush crowd out preferred vegetation while other unwanted plants keep livestock from grazing certain areas. Hay crops can be contaminated by thorns, barbs, briars and natural toxins from unwanted weeds. Fence rows disappear in a tangle of blackberries, thistles and multiflora rose. David Whitson, Ag Business Specialist for the University of Missouri Extension, told KODE, "By law, farmers and landowners are expected to control those weeds to keep them from spreading, because [noxious plants] either create health hazards to animals, or else they're difficult to control, or spread very rapidly and create extreme competition with other plants."
According to Whitson, the noxious weeds most commonly identified in Newton County are Musk Thistle and Johnson Grass. "The thing in particular about Johnson Grass is that not only does it spread by seeds, but it spreads by rhysome. So the other thing that makes it really difficult if it gets into a field like soybeans or corn where you're going to do tillage, and you go out and disc it, you make one plant into ten or fifteen plants."
Experts say that among the many methods of controlling weeds and invasive plants, herbicides are the most effective. But it's already too late in the season for chemicals to have much effect on plants like Musk Thistle. "It's best controlled in the Fall in October, early November, or else in March, early April", said Whitson. "Once it gets in the bolt where it has the flowering stage and puts the seed head on, you'd be best to let it stand till July and let the Musk Thistle Weevil feed on the seeds and lower the amount of seed production. The Musk Thistle Weevil feeds in the head. Right now, you can cut a head open and you can see these weevils down in the bottom eating the ends off the seeds."
Another problem plant is Spotted Knapweed. "It appears to be brought in when some of the utility companies came and did digging along some of the highways, and then they came back in with that mulch to re-seed the area, and apparently they brought some hay in from out of state that had Spotted Knapweed in it."
Whitson recommends you find out more about identifying and controlling noxious weeds by logging onto the University of Missouri Extension's website.http://extension.missouri.edu/explorepdf/agguides/pests/IPM1014.pdf