“So far, this disease has only been reported in Africa. However, if red leaf blotch is found in the United States, a recovery plan through the USDA-APHIS program has been developed that outlines a course of action to prevent it from spreading.”

Red leaf blotch symptoms include lesions on foliage, petioles, pods and stems. The fungus does not appear to be seedborne, but may be transported along with soil and other debris in grain. Yield losses of up to 50 percent were documented in Zambia and Zimbabwe in the 1980s.

“We don’t want to scare people because this disease has not been found in the United States,” Hartman said.

“But we do want growers to be aware of it because they are typically the ones to find new pathogens, pests and weeds in their fields. Our goal is to build awareness among crop specialists and producers so we can stay ahead of it.”

Hartman said more research is needed to develop molecular diagnostic techniques to identify this pathogen from other common foliar soybean pathogens, to provide better information on fungicide chemistry and application timing, to develop varietal resistance and gather more data to develop predictive models for potential containment and management.

To successfully reduce losses due to pathogens and pests, a number of practices used alone or in combination may be needed; these include cultural and seed sanitation techniques, pesticide applications, and deployment of soybean cultivars with resistance.

“Biosecurity of food crops is important because we don’t want to suffer food shortages — whether it’s due to natural disasters or pathogens and pests that we can sometimes control,” Hartman said.

“If you are talking about food and crop improvement, you are always talking about reducing diseases and pests.”

This article, “Crops that feed the World 2. Soybean — worldwide production, use, and constraints caused by pathogens and pests,” appeared in Food Security.

Researchers included Hartman, Ellen West and Theresa Herman of the U of I. Funding was provided by the Illinois Soybean Association, the North Central Soybean Research Program and the Elizabeth Hageman Endowed Graduate Research Fellowship.