Plant Health Initiative

Seedling diseases - Agronomic impact

Soybean seedlings at emergence. Stand reductions may or may not reduce yield. Photo credit: University of Nebraska

Pre- and post-emergence diseases of soybean are common in all soybean-growing areas of the United States. Seed and seedling diseases reduce stands in the spring, with severity varying from year to year. However, a stand reduction does not always mean a lower yield since the soybean plant is able to compensate for space.

From 1999 to 2005, losses to seed rot and seedling blights were estimated to be over 25 million bushels per year for the United States (Wrather, J. A. and Koenning, S. R. 2006. Estimates of disease effects on soybean yields in the United States 2003 to 2005. Journal of Nematology 38:173-180).

Infection by significant soybean pathogens such as Fusarium solani f. sp. glycines (the causal agent of sudden death syndrome), and Phialophora gregata, the brown stem rot pathogen also occurs in early vegetative growth stages. Infection often remains latent until the plant reaches reproductive growth stages.