Dorrance, A.E., D. Mills, A.E. Robertson, M.A. Draper, L. Giesler, and A.Tenuta, 2007. Phytophthora root and stem rot of soybean. The Plant Health Instructor. DOI: 10.1094/PHI-I-2007-0830-07

DISEASE:  Phytophthora root and stem rot of soybean

PATHOGEN:  Phytophthora sojae

HOSTS: Soybean: Glycine max, the cultivated soybean, is the primary economic host. Glycine soja, the wild progenitor of soybean, is also susceptible

Authors
Anne E. Dorrance and Dennis Mills, The Ohio State University
Alison E. Robertson, Iowa State University
Martin A. Draper, USDA-CSREES, formerly @ South Dakota State University
Loren Giesler, University of Nebraska-Lincoln
Albert Tenuta, Ontario Ministry of Agriculture, Canada

Figure 1a	Figure 1b

Phytophthora sojae is a soil borne pathogen that in the past has caused very large economic losses. During the late 1970s, 300,000 soybean acres (approximately 10% of total soybean production in Ohio) were lost due to P. sojae. This disease has since been effectively managed predominately through the incorporation of single-gene mediated resistance but quantitative or partial resistance has been used as well. In fact, today, we can repeat 100% loss by planting soybean cultivars that were popular during earlier epidemics. Without high levels of resistance to this pathogen, many soybean acres would be lost each year to this disease. Phytophthora doesn’t forget and it doesn’t go away!