Phytophthora Root & Stem Rot
of Soybean

How Does Disease Develop?

Phytophthora diseases

Populations of Phytophthora sojae

Example of a P. sojae population

Example of a P. sojae population

Intensive Soil Sampling P. sojae

Phytophthora sojae Resistance

What is a race/pathotype?

Variety A:
No Rps genes or Partial Resistance

Variety B :
Rps1a and No Partial Resistance

Variety C:
Rps1k and No Partial Resistance

Variety D:
Rps1k and High Partial Resistance

Variety E :
High Partial Resistance

Partial Resistance to
Phytophthora sojae

Genotypes and disease risk

Managing Phytophthora sojae

Partial Resistance

Partial Resistance to P. sojae

Rps genes + Partial Resistance

Partial resistance levels in
Ohio Soybean Performance Trials

Dealing with Phytophthora sojae
populations

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