With increased Xtend acreage, it is important for growers to be diligent when evaluating post emergent herbicide performance. Non-Xtend soybeans and various other crops are extremely sensitive to dicamba which disrupts the plant’s normal hormonal balance and stimulates rapid, uncontrolled cell growth.
Important Dicamba Injury Information to Remember:
- Plant injury symptoms don’t develop immediately after exposure.
- Injury symptoms will begin appearing on new growth.
- The most severe symptoms might not be noticed for 7-14 days.
- Leaves already fully developed when the plant was exposed will be less affected.
- Trifoliate leaves will have extreme cupping and most pronounced on the upper trifoliate.
- Low-dose exposure symptomology tend to be consistent.
When making field observations for dicamba injury symptoms, be on the lookout for cupping and strapping of newly emerged leaves to height reductions and injury to growing points. However, keep in mind there are other look alike leaf symptoms that are like dicamba injury. For example, Clopyralid (Stinger) from residues in the field from the previous year’s corn crop can be responsible for damage to soybean, symptoms typically appear by the V1 stage. Damage is usually associated with soil type or in streaks related to spray overlaps, rather than field wide injury.