P. gregata does not produce survival structures, but has the ability to overwinter as mycelium in decaying soybean residue.

Brown Stem Rot (BSR) may commonly reduce yield of soybeans by 10-30% on susceptible varieties,[4] up to 10 bu./acre in severe cases.

[4] Brown Stem Rot can impact most susceptible soybean beans in the north central states, especially during cooler late summer months.

The most effective form of management is disease resistance,[2] but crop rotation, tillage, SCN management, and changing the pH of the soil can also be effective [2][6] Phialophora gregata’s infection of a soybean plant is accompanied by browning of the plant’s vascular and pith tissues.

One can visualize signs by cutting open the stem in early stages of infection,[2] but symptoms do not become apparent until after the soybean pod formation.

[3] Disease from P. gregata is easily confused with Fusarium wilt, due to the similar vascular symptoms observed in both.

[10] The Phialophora gregata pathogen proliferates in stem tissues when soil has high moisture content and air temperatures remain near 60-75 degrees Fahrenheit.

[3] Additionally, the prevalence of Soybean Cyst Nematodes (SCN) can affect the growth of Phialophora gregata, the BSR pathogen.

[2] The Phialophora gregata fungus produces no survival structures, but can overwinter as mycelium [12] in decaying soybean residue.

[12] Infection initially occurs in the roots of young soybean plants, and then spreads to the stem (and foliage, depending on the strain).

Common techniques include crop rotation, tillage, selection and Soybean Cyst Nematode management.

Due to this, waiting until plant debris has decomposed (at least one full growing season) is the most effective way to control this disease[5].

[2] Soybean plants with resistance to both SCN and genotype A of P. gregata can grow normally, even when both pathogens are present.

SCN can be controlled using rotation to non-susceptible crops, seed treatments, variety selection and nematicides.