Phytophthora causes significant impact on soybean yields

"One of the things we've learned over the past five years, based on research, is that [Phytophthora and Pythium] are a lot more significant than we originally thought. And especially these cooler winters and springs we've been having [are] helping this pathogen survive."

Dr. Alison Robertson, Iowa State University

Phytophthora is the #1 Disease Impacting Soybean Yield.

More than 532 million bushels lost to phytophthora from 1996 to 2007.

Estimated suppresion of soybean yield in the U.S. from 1996 to 2007

Phytophthora Isolates Recoverd Chart

Phytophthora is prevalent in wet, heavy clay soils.

Phytophthora is a hidden threat to soybeans.

  • Heavy clay soils with poor drainage
  • Often found in compacted areas of field, such as entrances
  • Periodic rainfall ideal for severe disease
  • Warm soil temperatures of up to 85° F are optimum for infection
  • Often mistaken for herbicide damage

Phytophthora causes stand reduction and yield loss.

Damping-Off Phytophtora Damping-Off Phytophthora Sojae

Dair McDuffee, Valent U.S.A. LLC

Root and Stem Rot Root and Stem Rot Phytophthora Sojae

Martin Draper, USDA-NIFA, Bugwood.org

Root and Stem Rot Root and Stem Rot Phytophthora Sojae

Daren Mueller, Iowa State University, Bugwood.org