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Corn: Corn Flea Beetles

Author: OMAFRA Staff
Creation Date: 01 March 2002
Last Reviewed: 01 March 2002

Agronomy Guide > Pub 811: Corn > Corn Flea Beetles

Excerpt from Agronomy Guide for Field Crops (Chapter 3)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

  1. Description
  2. Life History
  3. Damage
  4. Scouting Technique
  5. Action Threshold
  6. Management Strategies
  7. Updates on Corn: Corn Flea Beetles
  8. Related links...

Description

Very tiny (1.8mm), black, shiny beetles with elongated hind legs used for jumping when disturbed.

Corn flea beetles leave long feeding scratches running parallel with leaf vein. Vectors of Stewart's wilt (bacterial leaf blight).

Plate 21. Corn flea beetles leave long feeding scratches running parallel with leaf vein. Vectors of Stewart's wilt (bacterial leaf blight).

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Life History

This pest overwinters as adults at the base of grasses. In the early spring, beetles emerge and mated females then lay their eggs in the soil close to the base of corn plants. Within 6 days, eggs hatch into larvae, which then pupate, and within 14 days, the adult beetle emerges from the soil. There are three to four overlapping generations per year. Only those generations occurring from early May to late June, during corn emergence are considered a potential problem.

Damage

Only susceptible varieties show yield loss. Long feeding scratches or window-paning are found on the leaves, usually running parallel with the leaf veins. Flea beetles vector Stewart's bacterial wilt (Erwinia stewartii), which shows up on the plant as linear lesions with wavy edges. Plants may wilt or become stunted from this disease.

Scouting Technique

Inspect five sets of 20 seedling plants per field to determine the presence and density of the beetle.

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Action Threshold

An average of five or more beetles per plant prior to the fourth-leaf stage may warrant control.

Management Strategies

Mild winters favour the survival of the beetle and bacteria over the winter. Early planting dates should be avoided for varieties susceptible to Stewart's wilt. It is uneconomical to spray corn with insecticides to protect against Stewart's wilt except in seed corn with highly susceptible varieties. Seed treatments are being developed for flea beetle control. See OMAFRA Publication 812, Field Crop Protection Guide, for chemical control options. (Order OMAFRA Publication 812)

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Updates on Corn: Corn Flea Beetles

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Related links...

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