Start thinking about early-season weed control in corn, advises Jim Ruhland, DuPont-Pioneer agronomist in South Dakota.

Controlling early season weeds is critical to achieving high corn yields, he says.

"It's most important to preventing weed competition in corn three to six weeks after planting. This period begins the V2 to V3 growth stage of corn, or when corn plants are about six to eight inches tall," he says.

His top tips:

1. A pre-emergent herbicide followed by a post-emergence herbicide program is the most reliable and effective weed control program.

Weeds were controlled early on the left and later on the right. Photo: DuPont Pioneer

2. Pre-emergence or post-emergence only herbicide programs can protect yield equally to a two-pass program, but they require careful management.

3. Soil-applied herbicides require light incorporation or rainfall within five to seven days of application. Lack of rainfall, uneven incorporation or excess rainfall can dramatically reduce herbicide performance and yield.

4. Throughout the growing season, take notes and photos of weeds and field conditions to aid in your herbicide management plan. If you are interested in taking pictures and notes via your smartphone, download the free Encircasm app.

5. Be sure to use herbicides with multiple modes of action to prevent herbicide resistance and to best manage post-emergent weeds.

6. If pre-plant/pre-emergence herbicides cannot be applied, apply post-emergence herbicides as soon as possible.

7. Include residual herbicides to extend control of weeds that are still germinating.

8. Do not cut the use rate. Use the recommended rate for the weed size.

9. Use high-quality adjuvants as directed on the product labels.

10. Be prepared to apply follow-up treatments to control escapes and late-germinating weeds.

Source: DuPont Pioneer