Weed Killer Concerns

Home Grown  by Keith Reed
An unpleasant side-effect to all the great rains we’ve had recently is the explosion in our weed growth. This has been especially true in vegetable gardens and ornamental beds where the exposed soil has been too wet to cultivate. The calls and damaged plant samples coming into the Extension office right now serve as a somber reminder for the need to take care with weed control products, especially those designed to control broad leaf weeds.

The vast majority of broadleaf weed control products contain 2,4-D (Dimethylamine salt of 2,4-D-Dichlorophenoxyacetic acid) or a closely related chemical. This active ingredient is found in hundreds of different products and can come in both liquid or granular forms. When used properly in accordance with the label instructions, this product does a great job at controlling most broadleaf weeds. The bad news is it is equally as effective at killing many of our desirable plants with tomatoes, potatoes, and grapes being some of the most sensitive.

“No problem”, you may say, “I’ll just be careful not to spray these plants”. If only it were that easy. This class of chemical moves very easily with the wind, traveling much farther than you might imagine. To make matters a bit worse, the liquid form of the product does not even have to make the trip with the wind. When conditions are right (higher temperatures and young, actively growing plants are a big part of this), even the vapor from the product can be enough to cause a problem.

Scientists use the term epinasty to describe the growth of the affected plant. Damage is characterized by stretching, twisting, and general malformation of the leaves and stems. Sometimes, the plants can recover and outgrow this, but oftentimes they do not. It can help to prune off the damaged portions since once the plant part is deformed, it is never going to regain its full function.

The take home message is one you’ve heard often if you are a regular reader. Part of the role of the product label is to warn you of issues like this, but ultimately, it is up to individual users of these products to use them correctly. Please read and follow the instructions. If you have questions after that, give us a call in the Extension office and we’ll try to help. If you do call, have the product label (or at least the brand name and active ingredient) close by.

For more information of this or any other horticultural topic, you can contact Keith Reed, the Horticulturist in the Payne County Extension office. Keith can be reached via email at keith.reed@okstate.edu, phone at 405-747-8320, or in person at the Payne County Extension office, located at 315 W. 6th in Stillwater.

Oklahoma State University, in compliance with Title VI and VII of the Civil Rights Act of 1964, Executive Order 11246 as amended, Title IX of the Education Amendments of 1972, Americans with Disabilities Act of 1990, and other federal laws and regulations, does not discriminate on the basis of race, color, national origin, gender, age, religion, disability, or status as a veteran in any of its policies
Article Archives