By Amit Jhala, Extension Weed Management Specialist
Soybean planting has started in Nebraska and it’s time to apply pre-emergence herbicides.
Six weeds have evolved resistance to glyphosate in Nebraska. The best way to effectively control resistant and other hard-to-control weeds is by applying residual, pre-emergence herbicides with multiple effective modes of action.
Several new herbicides recently registered in soybean are in this category and could be considered.
Flumioxazin-based herbicides are commonly used for weed control in soybean. They can be applied pre-plant or pre-emergence, but NOT after soybean emergence. This is applicable for herbicide products with only flumioxazin (such as Rowel, Valor) as well as when flumioxazin is a part of the pre-mix (such as Afforia, Envive, Enlite, Fierce, Rowel FX, Valor XLT, Fierce XLT, Trivence) or when flumioxazin is tank-mixed with other herbicides.
Flumioxazin-based herbicide premixes have shown excellent broad-spectrum weed control in soybean when applied pre-plant or pre-emergence. If growers are not able to apply them before soybean emergence, they must NOT apply post-emergence because severe crop injury may occur. Therefore, it is advisable to apply them within 3-4 days of planting soybean.
Application after soybeans have begun to crack, or are emerged, will result in severe crop injury. When flumioxazin-based herbicides are applied, it is also recommended NOT to irrigate when soybeans are cracking.