Ohio Farmers Warned: 15-foot Tall Ragweed Plants Resist Chems

CINCINNATI (TDB) -- Brace yourself, Ohio. An onslaught of herbicide-resistant giant ragweed appears on the horizon. Bad news for hayfever sufferers. But worse for farmers who can lose up to 70% of a soybean crop when the weeds establish themselves and shade out shorter plants. Giant ragweed can grow up to 15 feet high on stalks as thick as broomsticks.

Farmers who have serious infestations are being advised to give up on soybeans and switch to corn. The rest of us may have to reach for hankies and Visine.

Technically, giant ragweed is Ambrosia trifida, which roughly translates as a three-lobed leaf that is food for gods. Researchers say it is hardly a feast for a divine table.

A picture is HERE, and Marc Loux, an Ohio State University weed scientists, is all over farm publications this winter warning giant ragweed was found in three central and southwest Ohio counties last year that has developed resistance to glyphosate, a chemical used to control weeds. Researchers are cautioning farmers to be careful how they use weed control products year after year. A weed called marestail was among the first to discover how to survive. Now it is giant ragweed, and three or four in a square yard can devastate crop yields.

Farmers have been getting word on control techniques HERE. Purdue University and Ohio State say the weed poses a serious problem:

"It can germinate from late March through July. It is one of the first summer annuals to emerge in the spring and is often present before crops are planted. Best solution -- plant corn in fields with a history of giant ragweed control problems. Use a combination of pre and post herbicides in corn. The post herbicide treatment should include herbicides other than glyphosate, to ensure control of glyphosate-resistant plants."

David Beaulieu, who writes a gardening column for About Landscaping, says the plant was once thought to have value as a pioneer-day pharmaceutical. But now it is seen as a pest.

"As with so many plants considered baneful in the 21st Century, giant ragweed was used medicinally by the denizens of tougher eras. But when one thinks of the plant nowadays, one thing comes to mind and that is 'ragweed allergy.' Together, common ragweed and giant ragweed account for most of the hay fever experienced in North America in the fall. Symptoms of ragweed allergy are sneezing and runny nose, along with itchy eyes."

Click HERE to learn more from Beaulieu.

So, once again Mother Nature has found a way to outwit humans. Bugs, bacteria and now weeds have learned how to adapt and survive. They show remarkable resilience in the face of technology. Ma Nature is nothing to sneeze at, as the ragweed invasion shows.