Corn Rootworm Concerns

Corn rootworm is a pest that has often been overlooked in our trade area and is something that needs to be addressed going forward. We walked several fields throughout our trade area last season and saw increased numbers in most of the geography we cover. It is a pest that can be very devastating to not only yield but overall harvestability with yield losses estimated at up to over 50% of the total potential. The main impact of this pest is pruning of the main corn roots which results in less uptake of water and nutrients of the plant and results in the corn lodging or tipping over.

So how do we deal with this going forward?

Crop rotation is still the best option, but with extended diapause in Northern Corn Rootworm this is not always as effective as one might expect. Extended diapause means that a population of this insect species will lay eggs that require a few seasons of winter to hatch. Some recent work has shown that the eggs can lay viable in the soil for up to three years before they hatch. This means that once a population gets established other means of management must be used such as insecticide in furrow and the incorporation of traits that help control the pest. There are several options for insecticide that are effective against corn rootworm. These options can require a different delivery system depending on the type of planter setup that you currently have. Traits are also a good option, but they should be rotated with different traits to help slow down trait resistance. The third option for control is beetle bombing which is aerial spraying, but this is very difficult to time, and it is not a stand-alone method. Adults can emerge over a long period of time, and this is what can make timing this application difficult.

The main takeaway is that this pest must be monitored going forward and multiple methods of control should be used to preserve overall corn yields. We would like to thank you for your continued support of West Central Ag Services. If you want further information on this topic or others, please reach out to your local agronomist.

-Rick Walker