From BugwoodWiki

bean leaf beetle Photo by Natasha Wright, Florida Department of Agriculture and Consumer Services, Bugwood.org Taxonomy Kingdom: Animalia Phylum: Arthropoda Class: Hexapoda (including Insecta) Order: Coleoptera Family: Chrysomelidae Genus: Cerotoma Species: trifurcata Scientific Name Cerotoma trifurcata (Forster)

Author: Dr. Phillip Roberts, Dr. Paul Guillebeau, University of Georgia

Contents 1 Description 2 Hosts 3 Damage 4 Life Cycle 5 Control 6 Originally compiled from

Description

Adults vary in color but are typically reddish brown to yellowish with four black spots and marginal stripes. Spots may not always be present but a black, triangular-shaped marking is always present on the forward margin of the wings. Adults are 5 to 6 mm in length. Larvae are white and cylindrical with a black head and anal shield and reach a maximum length of 10 mm.

Hosts

Soybeans, peanuts, and various legume crops and weed species.

Damage

Damage to soybeans occurs primarily by leaf-feeding adults, however, adults will occasionally feed on developing pods. Larvae feed on plant roots but are not considered an economic problem on soybeans. Adults generally prefer to feed on the youngest plant tissue available. Defoliation is recognized as small, round holes between major leaf veins.

Life Cycle

Bean leaf beetles overwinter in leaf litter and other vegetation and emerge in early spring. Females lay 175 to 250 eggs in clusters of 12 to 24 in the soil at the plant's base. Eggs hatch in about a week, and larvae feed on roots for 2 to 4 weeks. The pupation period lasts about seven days. As many as three generations occur per year in southern areas.

Control

Treat based on defoliation thresholds. Soybean treatment thresholds:

Prior to full bloom: defoliation reaches 30 percent.

Full bloom until mid pod-fill: defoliation reaches 15 percent.

After full pod-fill: defoliation reaches 25 percent.

Originally compiled from

• Roberts, P. and P. Guillebeau. Bean Leaf Beetle. University of Georgia.