spotted cucumber beetle

Common

April to October

Fields, agricultural fields

Spotted cucumber beetle is a small skeletonizing leaf beetle. It occurs throughout the United States, in Mexico, and in southern Canada. It is common in Minnesota. It is found in fields, including agricultural fields. The larva feeds on the roots of corn, plants in the Cucurbitaceae (cucumber) family, and other plants. The adult feeds on the flowers, leaves, stems, and fruit of a more than 200 species of plants. As they feed they create holes in the leaves, scars on the stems, and pinholes on the fruit. They transmit bacterial and viral diseases. Spotted cucumber beetle is a vector for at least five plant diseases. It is a major pest to agricultural crops. Because of the wide variety of plants it damages it is considered one of the ten worst insect pests.

The body is oval, 3⁄16″ to 5⁄16″ (4.6 to 7.7 mm) long, and ⅛″ (2.8 to 3.9 mm) wide. When viewed from above, the head and most of the legs are clearly visible.

The head is black. The antennae are thread-like and long, more than half as long as the body. They have 11 segments. The first segment (scape), second segment (pedicel), and third segment (first flagelomere) are yellow. The remaining 8 segments are black. The antennae are close together at the base, about level with the middle of the eyes. They are flexible, and can project in various directions. The eyes are not notched.

The exoskeletal plate covering the thorax (pronotum) is rectangular, wider than the head, and and narrower than the base of the hardened wing covers (elytra). It is colored differently than the elytra, yellow to yellowish-red with no black markings.

The elytra are greenish-yellow, hairless, and long, concealing the entire abdomen. They have a distinct, narrowly flattened margin. There are six bold black spots on each elytron. The plate between the wing bases (scutellum) is small, triangular, and black.

The legs are mostly black. The base of the third leg segment (femur) is yellow. The last part of each leg (tarsus), corresponding to the foot, has five segments. However, the fourth segment is minute and is concealed within the heart-shaped lobes at the end of the third segment, making it appear that there are only four segments. The last segment has a pair of claws.

Roots of corn, plants in the Cucurbitaceae (cucumber) family, and other plants.

Flowers, leaves, stems, and fruit of a wide variety of plants.

Sources: 7, 24, 27, 29, 30.

There are three subspecies of spotted cucumber beetle. Only Diabrotica undecimpunctata howardi occurs in Minnesota.

Location: Woodbury, Minnesota

Location: Woodbury, Minnesota