U of Florida scientists find way to surgically strike out weeds that impede crop growth

By using a combination of fumigants, University of Florida scientists believe they can surgically strike out some weeds that otherwise get in the way of vegetable growth.

Researchers with the UF Institute of Food and Agricultural Sciences have shown that farmers can place fumigants in specific zones, rather than using a single treatment for every situation. For example, fumigants applied to a specific area where weed seeds germinate can reduce the number of weeds that grow. Researchers say this will help growers as they try to manage pests in areas where they cause the most trouble.

As a rule, growers manage pests by injecting fumigants into soil at the bottom of a raised bed to kill pests and pathogens in the bed of the soil. For the past several years, UF/IFAS researchers have worked to develop management zones.

"The concept of management zones is novel for Florida but also for other regions across the United States," said Nathan Boyd, a UF/IFAS associate professor of weed science. "For weed control, we are suggesting that you apply it close to the surface where the weeds grow."

It's important to knock out the weeds because they can impede the growth of tomatoes, bell peppers and strawberries, among other crops. A weed known as nutsedge reduces pepper yield by about 70 percent, and it can cut tomatoes by 50 percent, according to previous UF/IFAS research.

For the past several years, Joe Noling, a professor of nematology at the UF/IFAS Citrus Research and Education Center; Gary Vallad, an associate professor of plant pathology, and Boyd - both at the Gulf Coast Research and Education Center - have worked on developing the management zones for soil fumigants.

In a new study, UF/IFAS researchers adequately controlled weeds with a combination of dimethyl disulfide and metam potassium.

Boyd likened the weed-management zone to taking care of your lawn.

"Think about your lawn for example," Boyd said. "There are areas where weeds are worse than others, or areas where grass does not grow as well. If you want a healthy, nice-looking lawn, then you need to focus on the problem areas. What we have developed is a similar concept. If you control the weeds with the fumigants, there is no need to apply herbicides. The key is better use of pesticides, which can result in an overall reduction in pesticide use."

The new research is scheduled to be published soon in the journal Crop Protection.