Project Overview

Reports

Commodities

• Additional Plants: other

• Agronomic: corn, soybeans

• Ecosystem: Ecosystem

Target Pests

Practices

• Pest Management: decision support system, forecasting, monitoring/scouting, pesticide application timing, pesticide resistance management, pesticides, weather monitoring

U.S. corn and soybean production systems are heavily reliant on post-emergence applied herbicides. However, overuse of post-emergence herbicides combined with frequent resprays to control weed escapes has resulted in the rapid spread of herbicide-resistant weeds, necessitating increased use of soil residual herbicides with different sites of action and pre-plant tillage to provide additional control measures before the crop is planted. Soil residual herbicides work by getting into the soil solution and coming into contact with a germinating weed seedling right after the germination process has initiated. Freshly germinated weed seeds are also very susceptible to tillage control measures. Understanding and communicating to farmers and spray applicators about when weeds will be germinating and when peak weed emergence will occur allows for more timely applications of soil residual herbicides and the use of tillage to control germinating weed seedlings.

We propose to develop the Weed Emergence Scouting Tool (WEST). This product will be a real-time tool for monitoring first and peak emergence of giant ragweed and waterhemp in the Midwest to support more effective weed management with soil residual herbicides or tillage. Past research has identified the emergence sequence for numerous weed groups based on growing degree day (GDD) accumulations, but weed management historically has not utilized temperature-based scouting protocols. The WEST will integrate weed emergence and management knowledge with high-resolution weather and climate data to develop a first-of-its-kind tool that supports timely soil residual herbicide use and tillage.

Project objectives include:

1. Gathering field observations of first and peak emergence for giant ragweed and waterhemp and comparing results to known emergence sequences
2. Developing the Weed Emergence Scouting Tool (WEST), which includes GDD-based weed emergence climatology, real-time emergence tracking, and user-submitted emergence observations
3. Disseminating the WEST to key audiences across the region

Herbicide application timing, which is sometimes combined with pre-plant tillage, is critical for controlling the region’s most problematic weeds, including giant ragweed and waterhemp. GDD-based weed emergence information provides an opportunity for expanding the adoption of integrated pest management. In other words, farm advisors can better advocate for adjusting herbicide application timing, the mix of chemicals used, and the use of pre-plant tillage based on indicators of early spring first and peak weed emergence. Real-time information that targets better pre-emergence/pre-germination weed management can expand the uptake of integrated pest management techniques and would mutually benefit farmers and the environment.

Objective 1: Gather field observations of first and peak emergence for giant ragweed and waterhemp

Objective 2: Develop the Weed Emergence Scouting Tool (WEST)

Objective 3: Disseminate WEST to key audiences across the region