The soilborne fungi which cause boll rot survive on plant debris. Bolls turn dark brown and as rot progresses, the black smut-like fungus growth which can be easily rubbed off covers the boll surface. Diseased boIls become dark brown with a white to salmon-pink overgrowth of the fungus. The knots are smaller and less prominent than on more susceptible host plants. Careful digging is necessary to prevent stripping off infected roots, thus incorrect diagnosis.
Infestations are usually greater in sandier soils and occur in irregular shaped areas in fields.
Infected plants show a stunted growth, foliage discoloration and are often infected by the Fusarium wilt fungus. The sting nematode is more common on extremely sandy soils, primarily in the Coastal plains. This destructive pest severely reduces root development and plant growth. Secondary roots and right angle branching are reduced when the tap-root is attacked during the early growth stages. Sting injury is often followed by Fusarium wilt fungus infection.