Guard wheat and alfalfa against pests

By Scout Nelson

In many parts of South Dakota, winter wheat is approaching the heading or flowering stage. During this period, farmers must be particularly alert to fusarium head blight, commonly known as head scab. This fungal disease not only reduces wheat yield but also produces mycotoxins harmful to livestock.

Farmers should scout their fields now and consider applying a preventative fungicide during early flowering, when wheat is most vulnerable to infection. The timing of this application is crucial for effective protection against head scab. Farmers should also monitor local weather; rapid changes can accelerate the progression from heading to flowering.

Two valuable resources are available to assist farmers in assessing the risk of head scab. The Fusarium Risk Tool from the national Fusarium Head Blight Prediction Center and the Small Grains Disease Tool by the South Dakota Mesonet both offer risk evaluations based on local conditions and wheat variety susceptibility.

Alfalfa growers need to watch for alfalfa weevils, especially as the first cutting approaches. While activity is currently slower than usual due to cool evenings, higher activity is expected in southern counties as the season progresses. The SDSU entomology team, including Dr. Adam Varenhorst, continues to provide updates and management tips through the Pest & Crop Newsletter and on the SDSU Extension website.

Fields heavily affected by weevils may appear whitish or light brown due to defoliation. Some farmers may opt to cut hay early to mitigate damage, although this does not guarantee the elimination of weevils, which can continue to feed on alfalfa windrows.

To effectively manage weevil threats, field scouting with a sweep net and a 5-gallon pail is recommended. Walking in a ‘Z’ pattern and sampling 30 plants will help determine the presence and density of weevil populations.

By staying alert and using available tools and resources, South Dakota farmers can protect their crops from these significant pest threats, ensuring the health and productivity of their fields.

Photo Credit -gettyimages-gabrielabertolini