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14 Dec 2022
cornrootworm_silks

Corn Rootworm: Know What to Look For and Prepare Your Plan of Attack

The official start of winter is only a few days away.

And that means that corn rootworm eggs are there… overwintering in your fields… just waiting for spring…

Bent on destroying next year’s corn crop.

Corn Rootworm: Stages, Damage, and Scouting

In the summer and fall of each year, corn rootworm females lay eggs that will overwinter in the soil.

In mid-May, those eggs will begin to hatch, and the larvae will start attacking your corn plants. They first munch on the root hairs, then graduate to primary-root feeding—causing significant physiological damage to your corn.

corn rootworm1x1Then, usually in July, the adult beetles will begin to emerge from the soil to feed on pollen, silks, and other parts of the corn plant.

The primary concern? Damage during pollination.

Depending upon the number of beetles in your field, destroyed silks can result in few kernels on the ear, or nearly no kernels at all—and that means significantly decreased yields.

So how can you determine if you have a corn rootworm problem? Work with your LG Seeds agronomist to scout for larvae and adults using a variety of unique methods.

Addressing an Existing Problem

So, what can you do to address an existing corn rootworm problem?

Often, biological controls are minimally effective. However, depending upon what life stage you find the rootworm in (larvae or adult), you could fight off an existing infestation through an insecticide applied via your irrigation system, cultivator application during tillage, or foliar application (perhaps paired with fungicides). 5

When applying pesticides, always be sure to read and follow chemical labels. Your LG Seeds agronomist can help you construct a personalized control plan for you and your field(s).

Preventing a Potential Problem

We’ve discussed in-season control methods, but what can you do to reduce corn rootworm pressure on your farm for seasons to come? Here are some tips:

Rotate your crops: Although the rootworm may feed on the roots of a few other plants, corn is certainly their go-to meal. When their eggs hatch in the spring and the larvae find only soybean roots, you can bet that the extent of their growth, development, reproduction, and damage will be greatly limited. 

Control those weeds: Along with rotating your crops, round out your “starve them out” campaign with proper weed control. When corn is not present, corn rootworms will try to feed on some common weed species. Select the LG Seeds soybean varieties that work best for your herbicides of choice, and don’t give those bugs a chance—including in your soybean fields.

Select the right hybrids: If you and your agronomist determine that corn rootworm pressure may be an issue on your farm, select hybrids like LG55C32 and LG61C34, which both offer strong genetic protection against corn rootworms.

Utilize a seed treatment: Along with offering quality corn hybrids for your acres, LG Seeds provides farmers with a variety of seed treatment options that can be powerful weapons in your fight against corn rootworm.

Every field is unique. Some may have higher corn rootworm pressure than others, and LG Seeds is here to help you assess your risk. Work with your LG Seeds agronomist to assess corn rootworm pressure across your fields and develop the best strategy for you and your farm.