Identifying Pests During Seedling Growth

On this page
  • Cutworms
  • Damping-off
  • Darkling beetle
  • Garden symphylans
  • Green peach aphid
  • Flea beetle
  • Flea beetle damage
  • Wireworm

Check seedlings twice weekly for insects, and seedling disease. Blank spots in the field may be the result of cutworms, darkling beetles, flea beetles, damping-off diseases, and aphids. Use the photos below to identify seedling pests. Names link to information on identification and management.

Click on photos to enlarge

Identification tip: Cutworm larvae come in various colors and patterns, but always appear smooth skinned to the naked eye. Most species of cutworms reach 1 to 2 inches when fully grown. They usually curl up when disturbed.

Damping off
Identification tip: The taproot and lower stem are shriveled and darkened in seedlings affected by damping-off (right).

Darkling beetle
Darkling beetle
Identification tip: Darkling beetles are dull bluish black or brown beetles that chew off seedlings or feed on foliage. They can be distinguished from the predaceous ground beetles by the enlargement of the segments at the tip of the antennae.

Darkling beetle
Darkling beetle damage
Identification tip: Darkling beetles chew off the seedling near the soil line.

Garden symphylans damage
Identification tip: Garden symphylans may damage seedlings before or after emergence and may slow the growth of larger plants. Damage usually is concentrated in relatively small areas and recurs yearly.

Green peach aphid
Green peach aphid
Identification tip: Green peach aphid is dark green to yellow, with indefinite darker stripes on the abdomen, and no waxy bloom.

Flea beetle damage
Flea beetle
Identification tip: Flea beetles are tiny dark beetles with enlarged hind legs. They jump when disturbed.
Flea beetle damage
Flea beetle damage
Identification tip: The small pitting in the leaf surface of this seedling is typical of flea beetle damage.
Identification tip: Wireworms are shiny, slender, cylindrical, hard-bodied, wirelike, yellow-to-brown larvae. They feed on tomato seeds and burrow into seedling stems.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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