Review of Pythium Species Causing Damping-Off in Corn

Abstract

Seedling blights and root rots caused by Pythium species account for almost US$25 million in annual losses to corn (Zea mays) production in the United States and Ontario. Variations in annual rainfall and increasing use of no-till agriculture can favor soilborne pathogens like Pythium. To date, 44 species have been reported as pathogenic to corn in the United States. The average annual corn planting date in the United States has shifted approximately 1 week earlier in the past decade, exposing young corn plants to longer germination periods of generally cooler temperatures, favoring attack by Pythium. Optimal temperatures, aggressiveness, and response to chemical and biological treatment options vary by species. This review consolidates the species of Pythium reported as corn pathogens in literature to date. It also provides an insight into management strategies and discusses variations in fungicide sensitivity observed in corn-related Pythium species.