Sweet Corn

Visual Description:

Ears show irregular patterns of missing or poorly filled kernels. The cob may have large sections with no kernels or kernels that are small and shriveled. This often appears in a random pattern throughout the ear. The problem is most noticeable when husking the corn, revealing gaps in the kernel rows. In severe cases, entire sections of the ear may be barren.

Visual Description:

Damage typically starts at the ear tip, with larvae feeding downward through the kernels. The worms are variable in color (green, brown, or pink) with light stripes, growing up to 1.5 inches long. Fresh silk shows signs of feeding, and brown frass (droppings) is often visible. When husks are pulled back, damaged kernels and the earworm itself may be found.

Visual Description:

Large, silvery-white to grayish swellings (galls) form on ears, tassels, or stalks. Initially smooth and firm, galls eventually burst open revealing masses of powdery black spores. Affected areas can be several inches in diameter. Early infection can cause significant plant deformation. While some cultures consider smut a delicacy, it renders the corn inedible for most markets.

Visual Description:

Early symptoms show as pale green to yellow streaks along leaf veins. These streaks eventually turn brown and die. The entire plant may be stunted and wilt, especially in young plants. When cut lengthwise, stalks show brown discoloration in the vascular tissue. Severely affected plants may die before producing ears.

Visual Description:

Symptoms begin with yellowing of older leaves in a V-shaped pattern from the leaf tip to the base. The yellowing progresses up the plant as nitrogen is moved from older to newer leaves. Stalks may be thin and spindly. Ears may be small with poor tip fill. In severe cases, lower leaves die and overall plant growth is stunted.

Visual Description:

Corn stalks are often pulled down or broken at about ear height. Husks are partially or completely stripped from ears, with kernels eaten from the cob. Multiple ears may be damaged in one night. Characteristic tracks or droppings may be found nearby. Damage typically occurs as corn approaches maturity.