EPA approves dicamba herbicides with new rules for Mid-Atlantic growers
By Kurt Vollmer, Ph.D., Extension Specialist, Weed Managment
After a two-year ban, the Environmental Protection Agency has approved three dicamba-based herbicides (Engenia®, StryaxTM, Tavium®) for use on dicamba-tolerant soybean crops, giving Mid-Atlantic growers another tool for weed control heading into the growing season.
Farmers across states such as Maryland, Delaware and Virginia, where soybeans are a major crop, should pay close attention to new federal requirements tied to dicamba use.
Growers may apply dicamba no more than two times per season, with each application limited to 0.5 pounds per acre. Each application also must include 40 ounces per acre of an approved volatility-reduction agent to reduce the risk of off-target movement, a concern in areas with smaller field sizes and neighboring specialty crops.
The EPA also requires farmers to adopt runoff and drift control measures to protect endangered species. Each field needs at least three runoff mitigation points. Fields located in pesticide use limitation areas must meet a higher threshold of six points from the agency’s conservation list.
Temperature restrictions will play an important role. While there are no cutoff dates, if forecasted temperatures are between 85 and 95 degrees on the day of application or the following day, growers may treat only half of their planted acres at one time. The remaining acres may be treated two days later.
Dicamba cannot be applied when temperatures are expected to exceed 95 degrees. Farmers should plan applications carefully and monitor weather conditions closely, particularly during periods of high humidity and temperature swings common in the region.
Previous requirements remain in effect, including mandatory applicator training, spray buffer zones and other weather-related restrictions designed to protect neighboring fields, waterways and residential areas. Growers should review product labels in full to ensure compliance with all application requirements.
Even though dicamba can be applied to dicamba-tolerant soybeans, farmers should not rely on this herbicide alone for weed control. Dicamba-tolerant soybean systems, such as XtendFlex®, also allow the use of other herbicides, including glyphosate and glufosinate, often in the same tank mix. This flexibility helps growers build a more comprehensive spray program and slow the development of herbicide resistance.