We received various digital inquiries with strange tissue distortion. Spring is a good time to remember not all plant injuries are caused by a pathogen like bacteria or fungi. Some symptoms are caused by abiotic (non-living or environmental) factors, including herbicides.
Herbicide damage can be challenging to diagnose because many of the symptoms may look like those caused by biotic factors (pathogens). Symptoms are varied and depend on several factors including the type and amount of herbicide, location of the symptoms on the plant and more.
If you are applying herbicides, it is important to pay close attention to the instruction on the label as well as environmental factors like wind and wind speed. If plants are damaged by herbicide, they may or may not recover, depending on the severity of the damage.
The Iowa State Plant and Insect Diagnostic Clinic does NOT test for herbicide residue in plants, but can help you investigate if a pathogen is causing the symptoms.
For more information on identifying, preventing and managing herbicide damage, check out this encyclopedia Understanding and preventing herbicide injury.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 8, 2020. The information contained within may not be the most current and accurate depending on when it is accessed.