Western-Diabrotica v. virgifera,
Northern-Diabrotica barberi

Coleoptera: Chrysomelidae

Identification
• The adult western is a yellow, ¹/₄" long beetle with black stripes and a yellow underside. (a)
• The adult northern is a greenish, ¹/₄" long beetle. (b)
• Larvae are slender, white, and up to ¹/₂" long.

Damage
• Adults feed on the green silks of sweet corn, preventing pollination and ear fill. (c)
• Adults feed on the petals of sunflower, daisy, black-eyed Susan, and many other flowers. They also damage cucumber and squash blossoms.
• Northern adults feed on the pollen of many flowers without causing damage.
• Larvae feed on the roots of corn. This causes reduced yield and the stalks to fall over.

Management
• Rotating sweet corn location annually in the garden avoids larval damage.
• Highly prized blooms can be covered with nylon netting to avoid attack. Note that insecticides applied to blooms may kill bees and other pollinating insects.
• Insecticides may be needed to protect green corn silks.