Value of a Preemergence
Effective Weed Control is About Weed Management
The key to harvesting the highest yield from every field is to incorporate a diversified weed management program. Such a program would include a residual herbicide along with Roundup® for postemergence control.
View the Soybean Practices and Weed Management Strategies Crop Pro Training Module.
Whether they are applied in the fall as part of a burndown program or in the spring, preemergence herbicides with long residual activity serve to prevent weeds from robbing crops of vital nutrients, sunlight and water, thereby threatening yield. In addition, fields that are weed free tend to dry and warm up more quickly, allowing growers to plant earlier.
Benefits of Using Preemergence Herbicides
| Benefit | Spring | Fall |
| Provides for a clean seed bed at planting time | yes | yes |
| Fields dry out more quickly and have warmer seed beds | yes | yes |
| Prevents winter annuals from going to seed in the spring | no | yes |
| Reduces selection pressure on postemergence herbicides by helping to control tolerant or resistant weeds | yes | yes |
| Provides seed beds that are less attractive to insects like cutworms and stinkbugs | yes | yes |
| Provides superior control of winter annual and perennial weeds such as dandelions, henbit, marestail, mustards, pokeweed, quackgrass, downy brome, etc vs. spring applied herbicides | yes | yes |
Authority Herbicides Can Help Stem Resistance
Sixteen weed species were confirmed as glyphosate resistant worldwide in 2011. One way to manage resistance is to control the number of glyphosate applications. Applying a preemergence herbicide is a good practice for reducing the number of glyphosate applications, thus reducing selection pressure to glyphosate.
