Ragweed a foe to farmer, allergy sufferers

-A A +A
By Bryce Roberts

Ragweed is a common foe both to allergy sufferers and to crop producers. In late summer, people can suffer allergic reactions associated with plant pollens, often ragweed plants. Ragweed also has the potential to severely interfere with crop production and greatly reduce crop yield.

The phrase “hay fever” often is misleading. It might seem that hay fever is caused by cut hay, however; you can usually blame those reactions on ragweed.  Ragweeds are native species that grow throughout the United States. Individuals who are sensitive the plant’s pollen are usually very aware of its presence. When plants begin to flower in August and early September, the airborne pollen is the culprit for the severe irritation to sensitive individuals. When exposed to the oil the plant produces, some people develop dermatitis effects.

Ragweed also can impact agricultural production, especially when present in corn, soybeans and pasture fields. If you don’t adequately control it, ragweed can cause significant crop yield loss and reduce pasture productivity. The economic impact of ragweeds on crop production is a combination of the yield loss and the cost of control efforts.

You can find three distinctly different ragweed species in Kentucky: common ragweed, giant ragweed and a lesser known species called lanceleaf ragweed. All these species are summer annuals and they only reproduce by seed.

Common ragweed is the most widespread and common of the ragweed species in the United States and it can grow up to 30 inches in height. These common plants tend to be slightly branched, but are best distinguished by their deeply divided leaves with a lace-like appearance. As the plant matures, slender stalks near the top of the plant contain green flowers that are not showy, but they do produce a bountiful crop of yellow pollen.

Giant ragweed matures into a much larger plant compared to common ragweed.     Kentucky farmers sometimes call it “horseweed” because it can grow up to 10 feet in height. Its leaves are simple, forming three to seven deep lobes, or occasionally, no lobes. As the plant matures, it can also have green flowers on a slender stalk. The giant ragweed also is capable of producing a bountiful crop of yellow pollen and new seed.

You’re more likely to find the lesser known lance-leaf ragweed in pastures, hay fields and other non-cropland sites. It can grow up to 36 inches in height and its leaves have a simple, somewhat lance-like appearance with three distinct points – the center point is larger than the two on each side.

With the end of summer, comes ragweed pollination. So allergy sufferers be aware, but as you sneeze, don’t forget those ragweeds don’t just impact your health, but they are also likely wreaking havoc on your local farmers.

Feel free to contact me at your Spencer County Cooperative Extension Service at 477-2217 or you can email me at broberts@uky.edu.  Visit our website at www.spencerextension.com.