Be on the Lookout for Disease

Diseases can and do cause economic losses for Mississippi soybean farmers. 

“Following the extended periods of cooler-than-normal weather conditions, as well as excessive rainfall in some parts of the state, disease calls have increased,” Tom Allen, Mississippi State University pathologist says.

Diseases Spotted
According to Allen, farmers are most likely to spot these diseases: Septoria brown spot, frogeye leaf spot and taproot decline.

“Those three are the biggest problems right now,” he says. “Most of the diseases have been really quiet up to this point.”

Best Management Practices
Before using a foliar fungicide, Allen advises farmers to scout and determine the type of disease and products to use.

When analyzing troublesome spots on soybean plants, Allen tells farmers to be aware of herbicide leaf spot, which indicates herbicide injury instead of disease. 

“Clear and correct plant disease diagnosis is important, especially since farmers are using multiple trait technologies,” says Allen, who has received 20 to 30 calls a week about spots that were caused by herbicide, not disease. 

“Keep in mind that something can drift a tremendous distance, and take that into consideration before making the decision to apply fungicide,” he says.

Farmers can proactively implement best management practices now to curtail fungicide resistance:

• Know common diseases – for your region and your fields. 
• Choose a resistant variety.
• Use crop rotation.

Harvest Effects
Allen says that no disease reports at this point should affect harvest though he rarely makes predictions.

“Disease conditions can change rapidly,” he says. “It really depends on the environment, but if it remains the same for the remainder of the season, I don’t foresee any major problems developing.”

For the latest disease information, check out Allen’s reports at www.mississippi-crops.com. Farmers can also download or order the Mississippi Soybean Scouting and Management Guide here.