Phytophthora root and stem rot appearing in soybeans
In the absence of specific information for fields with recurring Phytophthora issues, current strategy would be to plant varieties with Rps1k, Rps3a, Rps6 or a combination thereof (stacked). Farmers should also try to select varieties with higher levels of field tolerance, which is a general non-race specific type of resistance. Most seed catalogues will have a field tolerance rating for Phytophthora. Since resistance genes for Phytophthora are vulnerable to defeat from new emerging races, farmers should not depend solely on major gene resistance. Therefore integrating several management strategies is necessary for effective management of this disease.
Improving drainage (avoiding soil compaction and draining wet spots) lessens chances of Phytophthora infection. Fungicide seed treatment is recommended for fields with a known history of damping-off (see the Soybean Seed Treatments section of the 2013 South Dakota Soybean Crop Protection Guide publication). Use of fungicides as an in-furrow or banding application, although effective, has not generally been incorporated into soybean production because of product costs.