By Ankit Yadav and Amit Jhala
Early-season weed control is crucial to prevent crop-weed competition and potential yield loss, especially in soybean, where effective post-emergence herbicides are limited. When adequate soil moisture and warm temperatures promote rapid weed germination and growth, soybean fields can quickly develop dense weed infestations (Figure 1) that require timely post-emergence herbicide application for effective control in no-till soybean production system.
When applying post-emergence herbicides, it is essential to consider the soybean growth stage or pre-harvest interval to avoid soybean injury and herbicide residue in the seeds. Herbicide labels specify the maximum soybean growth stage at which broadcast herbicide applications can be made (see Table 1), and these guidelines should be followed closely. When using a mixture of herbicides, always adhere to the most restrictive label instructions among all products included.
How to Determine Soybean Growth Stage
- Restrictions on postemergence herbicide applications in soybean are based on the growth stage or the pre-harvest interval (PHI).
- These restrictions are typically expressed as a specific soybean growth stage or PHI, and sometimes both are provided (see Table 1). When both are listed, follow the most restrictive requirement.
Source : unl.edu