If you have corn rootworm (CRW) pressure or losses, a smart management strategy can protect your yield and your ROI. This article covers the most important things to know and do to manage CRW in your fields.
Corn rootworm pressure causes yield loss and economic impact
CRW damage costs farmers an average 15% yield loss per node of injury☆ and can cost farmers up to $1 billion a year. Larvae feeding on roots leads to yield loss, and adult CRW beetles can interfere with pollination by feeding on pollen and clipping silks and lay eggs in the soil that endanger future corn crops. At harvest time, CRW damage can cause root lodging that 1) slows harvest pace, increasing wear and tear on combines, 2) increases the risk of not getting ears in the combine head and 3) causes incremental yield loss above and beyond normal lower yields from feeding on roots. Additionally, corn rootworm has evolved in ways that make control more challenging. So even if you rotate from corn to another crop, extended diapause in Northern corn rootworm can allow eggs to survive two or more years in the soil until corn is planted again.
Corn rootworm management requires a long-term strategy
Corn rootworm is a difficult pest to manage, to the point that repeated use of the same single management practice will eventually end in disappointment. There is no silver bullet, but smart planning and hybrid selection are key to building a sustainable, multi-year management plan.
Effectively managing corn rootworm requires:
- A multi-year, field-by-field approach
- Attention to geographical location, crop rotation history and CRW risk levels
- Multiple control methods as and when needed
Four crucial Corn rootworm management practices
Understanding CRW presence and pressure through scouting or beetle trapping is an important first step in developing management plans. Once the relative risk level is understood, the following management options can be considered independently or in combination as part of a multi-year integrated management plan.
Your CRW management plan should include the use of different corn rootworm control methods in different years to help minimize the adaptation of corn rootworm to one technology. The plan may need to change each season, depending on pressure, but having it in place will give you a head start. Your strategies should include:
- Crop rotation: Rotation to a non-crop host can disrupt the life cycle of CRW, even in areas with extended diapause.
- Multiple modes of action CRW traits: Choose corn hybrids with traits like the Duracade™ and Durastak™ trait stacks that have more than one CRW trait.
- Soil-applied insecticides for larvae control to reduce root damage.
- Foliar-applied insecticides for adult beetle control to minimize silk clipping and reduce egg laying.
The value of corn trait stacks with multiple modes of action
Corn hybrid trait stacks with multiple modes of action against CRW are a key tool in managing CRW pressure, especially on continuous-corn acres. The Duracade™ trait stack and the Durastak™ trait stack (available for the 2027 crop year) both carry a unique combination of Bacillus thuringiensis (Bt) CRW traits, which expresses a protein that binds differently in the gut of CRW than any other trait on the market.