Biological Control of Corn Rootworm in Conventional and Organic Corn Production

View the project final report

Commodities

• Agronomic: corn

Practices

• Animal Production: feed/forage
• Crop Production: continuous cropping, crop improvement and selection, reducing production costs associated with corn rootworm management costs (using non-Bt-CRW corn seed or eliminate soil insecticide)
• Education and Training: demonstration, extension, networking, on-farm/ranch research, workshop
• Farm Business Management: budgets/cost and returns, financial management, risk management, whole farm planning
• Natural Resources/Environment: biodiversity
• Pest Management: biological control
• Sustainable Communities: new business opportunities, sustainability measures

Western corn rootworm (CRW), Diabrotica virgifera virgifera LeConte, is one of the most damaging insect pests to U.S. agriculture with damage and control costs exceeding $1 billion annually. Historically, this insect species has been managed using soil insecticides, crop rotation and most recently, corn varieties that are genetically modified to contain a toxin to kill feeding corn rootworm larvae (CRW-GM). Currently, all of these technologies are failing in areas across the US corn production. While CRW populations are not economically damaging every year in the Northeast, the damage is economically significant in the years of moderate to high populations. As a result, farmers growing corn for multiple years in a field, use CRW management technology each year at planting to prevent potential losses.

With rapidly increasing CRW-GM seed costs, reduction in efficacy, continued eastward movement of the rotation resistant variant, low milk prices and increasing pressure on the milk producers by milk processers to produce GM free milk for public consumption, producers are looking for alternatives for rootworm control. On organic farms, biological control of soil insects (corn rootworm. wireworm) will decrease damage and increase yield.

In a 2014 research project, native NY EPNs were inoculated in a first-year corn field and continuously planted to corn through 2018. In 2016, two years after inoculation, an economic population of CRW larvae were present in the field plots with the untreated check plots suffering almost two nodes of roots destroyed, an economically damaging level. In the EPN treated plots (inoculated just once in 2014), EPNs protected corn roots from CRW larval feeding and plants only suffered 0.25 of a root node damage. This level of protection rivaled that provided by CRW-GM events planted in the same trial. Within this research project, economically damaging CRW populations did not materialize in 2017 or 2018 seasons. However, the EPN populations in the soil have remained high enough to respond to the next economically damaging outbreak of CRW larvae. An ongoing set of experiments in the Hudson Valley, NY under organic production indicate that persistent biocontrol nematodes also reduce root feeding damage from wireworms.

We anticipate the cost to inoculate corn fields in the Northeast will range between $50-100 per acre. Typical differential cost between GM and non-GM corn varieties is $50 per acre. Under organic production, the cost of biocontrol nematodes would be returned to the farmer through reduced damage from both wireworms and corn rootworm and increased yield.

Fifty farms in NY, VT, and PA will implement biological control on 500 acres of corn to manage corn rootworm and as a result will reduce production costs by $50 per acre by reducing corn rootworm management costs (using non-Bt-CRW corn seed or eliminate soil insecticide).