Biology and Management of Corn Anthracnose

The fungus Colletotrichum graminicola causes corn anthracnose, a damaging disease in the U.S. Corn Belt and many other locations in the world where corn is grown. The anthracnose syndrome encompasses fungal attack of most corn tissues throughout the plant\u27s development. Anthracnose leaf blight (ALB) and anthracnose stalk rot (ASR) are of particular concern because of their effects on corn yield. Estimated grain yield losses due to anthracnose range from zero to 40%, depending on hybrid, environment, timing of infection, and other stresses. Anthracnose is a not a new disease, having been documented in North America since 1855. It emerged as a disease of economic consequence in the early 1970s in several north central and eastern U.S. states. Widespread epidemics of the 1970s and early 1980s were variously attributed to new biotypes of the fungus, corn hybrids with increased susceptibility, wet cloudy weather that favored the disease, and changes in cultural practice that increased survival of the fungus and availability of infective spores. There is little doubt that the general increase in anthracnose over the last 25 years is associated with regional increases in infected corn stubble remaining on the soil surface as a consequence of conservation tillage. Anthracnose is widespread today in U.S. corn production. In general, modern corn hybrids are less susceptible to both ALB and ASR than were prevalent hybrids of 20 years ago. Yet, sporadic epidemics resulting in yield loss still occur when plants are exposed to abundant spores and favorable weather conditions. Yield losses associated with ASR have been particularly common in plants injured by the European corn borer. In the late 1990s, there is an apparent resurgence of anthracnose as a production problem in some areas