Optimizing Natural Fungi to Control Pigweed Dr. Burt Bluhm, University of Arkansas Professor of Entomology and Plant Pathology

Burt Bluhm, professor of plant pathology at the University of Arkansas System Division of Agriculture (UADA), continues his research to find the bioherbicide that best targets Palmer Amaranth, commonly known as pigweed.

“Palmer Amaranth is one of the most important weed problems facing soybean producers in Arkansas and a lot of the U.S.,” Bluhm said, “it's a very difficult weed to control and there is a lot of uniqe aspects about its biology that make it very persistant.”

The bioherbicides Bluhm and his team created harness the natural pathogens they collected from pigweed in the first phase of the project. The bioherbicides also weaponize those pathogens to target pigweed and not the crop. So far, the bioherbicides they’re studying seem to be more effective than other options currently available to producers.

The approach of this project differs from what others have done and are doing. By exploring naturally occurring fungi that attack pigweed without harming soybeans, this research is opening the door to affordable new control options that can be produced domestically, reducing costs and creating local economic benefits.

“Our goal has been to explore biological control alternatives in which we utilize naturally-occurring fungal pathogens of Palmer Amaranth that specifically target pigweed,” Bluhm said.

Between 2016 and 2023, Burt and his team collected diseased pigweed plants from Arkansas fields, many from areas where herbicides had already failed. From more than 300 fungal samples, four strains emerged as the most promising candidates for bioherbicide development. These fungi have been shown to weaken, stunt and even kill pigweed while leaving soybeans unaffected.

Looking ahead, Burt is working to develop these strains into field-ready bioherbicide products. His research includes testing application methods, refining large-scale production and exploring how these fungi can be used in combination to reduce resistance. By developing reliable bioherbicides, Burt’s work aims to give Arkansas soybean farmers new tools to protect yields and ensure long-term success in the fight against pigweed.

Watch the full Field to Film: Featured Research video series here to learn more about current checkoff-funded research projects.