The recent extended period of cloudy weather and high soil moisture may have resulted in certain crops growing rapidly and developing a thinner than “normal” wax layer, called the cuticle, on the leaves. This thinner cuticle is more easily penetrated by postemergence herbicides. Warm temperatures during the cloudy moist period will increase the speed of growth and the thinness of the cuticle.
To reduce the risk of crop injury from postemergence herbicides this week:
1. Reduce the amount of spray additives used to the minimum labeled amount.
2. Use nonionic surfactants instead of oil concentrates when the herbicide label gives you a choice.
3. Do NOT add any surfactant, oil concentrate, or other additive if the label allows application alone.
4. Do NOT add liquid fertilizer to the spray solution, even if the herbicide label suggests it as an option.
5. Delay treatment of crops that are marginally large enough to treat according to the herbicide label.
6. Delay treatment until the crop has experienced 3 to 5 days of bright, clear, warm, dry, and sunny weather before applying postemergence herbicides. The cuticle thickens when the weather turns warm, sunny, and dry.