Dicamba Drift Issues in South Dakota
What does dicamba off-target movement do to soybeans that are not genetically tolerant to the herbicide? This question has been raised many times over the past month in South Dakota as more dicamba is being applied to fields with the introduction of dicamba-tolerant soybeans to the market.
The products available today for broadcast control of weeds in soybeans was lacking in some agronomic situations to control problematic weeds like common waterhemp and kochia. Dicamba has been proven to control these problematic weeds.
Non-Tolerant Crop Impact
Many crops are quite intolerant to dicamba off-target movement. Soybeans are one of the most sensitive crops to off-target movement. There is a possibility drought may increase effects of herbicide damage on these crops, and most of South Dakota has been in some form of drought throughout this growing season.
Soybean Damage Symptoms
- Cupping of trifoliate leaves, extreme cupping depending upon the level of the exposure.
- Leaf veins impacted tend to assume parallel orientation and unaffected leaf veins are “net” like in their patterns.
- The tips of the cupped leaves could often be brown or cream-colored, especially if the above mention symptoms are observed.
- With plant exhibiting the mentioned symptoms plant stunting may occur.
- Pod development may be hindered, depending upon timing of exposure.
Symptoms of dicamba damage are usually apparent, and can be determined by testing a plant sample for residue. Identifying how it got there is not as apparent.
The South Dakota Department of Agriculture is collecting information on possible dicamba drift through a Dicamba Damage Survey. Contact the SDDA 605.773.4432 for more information on the survey.