Two main options are available for managing CRW with cultural management. These two options are crop rotation and altering the planting date.
Crop rotation is one of the most economical ways to manage CRW. Since corn rootworms feed primarily on the roots of corn plants, rotating the field out of corn production eliminates the food source. Therefore when the field is planted to an alternative crop, such as soybean, the larva from the rootworm eggs that were laid the previous field season (in corn), have now hatched in this year’s soybean field and will die due to lack of food.
The second cultural management option is to alter the planting date of the corn crop. Corn rootworm beetles do more feeding and egg laying in fields that are pollinating, which also tends to coincide with beetle emergence. The pollinating fields offer fresh green silks from the ear shoots as well as pollen from the shedding tassels. By altering the planting date and planting corn earlier in the spring, pollination will be near completion or completed during beetle emergence. This will reduce the number of beetles laying eggs and feeding on developing ears. The other advantage to planting early is that the root systems of the plants will be more developed and better able to withstand feeding damage from CRW larvae.
Though these two management strategies offer the producer some positive alternatives for protecting the field from CRW, there are some disadvantages to using crop rotation or an early planting date when managing corn rootworm. Rotating from field corn to an alternative crop, such as soybeans or grain sorghum, the producer faces a potential loss in revenue. Altering the planting date of the corn crop is a viable management option against CRW but is not a guarantee. Differences in temperature and weather events affect crop growth and CRW development. If corn flowers late, and beetle emergence occurs early, significant silk clipping may occur.