Corn Flea Beetle

Description

Corn flea beetles are very small, shiny, round, black/brown beetles that jump readily when disturbed.

Flea Beetle

University of Kentucky Dept. Entomology

Damage

These beetles are leaf feeders. They make small feeding scars on the surface giving leaves a gray, frosted or bleached appearance. Damage is generally serious on plants less than six inches tall. Flea beetles also may transmit Stewart's wilt or bacterial leaf blight on field corn. This is of particular concern during cold, wet conditions that favor development of the disease.

Pest Activity

Please note: These dates are approximations only. This calendar was constructed using data from Kentucky, USA. These dates may not apply in your area. You may wish to contact your county extension agent or agricultural consultant for information tailored to your locality.

IPM Techniques and Scouting Procedures

• Flea beetles occur in plantings until mid-June. Check corn from emergence until plants are 12 inches tall. Flea beetle stress may be great on late-planted corn. Fields that were planted early may also show noticeable damage.
• Examine 20 plants in each of several locations and rate for feeding damage according to the following scale:

0 - no damage or scratch marks

1 - scattered scratch marks on less than 50% of the plants; plants appear healthy

2 - feeding on new leaves of 50% or more of the plants; some leaves whitish

3 - leaves turning brown, plant dying

• Also, estimate the number of beetles on each of the 20 plants. This must be done carefully because the beetles will jump at the slightest disturbance.
• Economic Threshold: Some plants have been killed or leaves are taking on a whitish cast--especially if the field has a history of Stewart's wilt.

References and Additional Information

• IPM-2 Kentucky Corn IPM Manual
• ENTFACT 302 - Sweet Corn Pests

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