Cotton seedling disease pathogens can attack and kill cotton seeds or seedlings or reduce the viability of cotton plants in several ways. Within hours after planting, the seeds are attacked by these fungi before the seed can germinate, which results in pregermination decay of the seed. Postemergence damping also may occur, which means that the cotton seedling is killed after the seed has germinated and emerged above the soil surface. Seedling root rot also may occur up to several weeks after planting and often kills the tap root, causing the cotton plant to respond by producing secondary roots. While seedling root rot may not kill the plant outright, the cotton plant will have a shallow root system, which leads to a loss of vigor of the plant and thereby reduces yields.
Producers have several options to manage cotton seedling disease.
Crop rotation also helps, but often is not a viable management option due to economic differences in crop values. Also the wide host range and the ability of these seedling disease organisms to survive as saprophytes reduces the effectiveness of crop rotation. The most reliable and economic method for seedling disease control is the use of fungicides. Fungicides are the least toxic of the pesticides to warm-blooded animals and they have specific toxicities to the fungi that they control. Cotton seedling disease management research has been conducted at the AAES's Tennessee Valley Research and Extension Center in Belle Mina, the Wiregrass Research and Extension center in Headland, and the Prattville Experiment Field.