How to Manage Pests
UC Pest Management Guidelines
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. Predaceous ground beetles are usually shiny and sometimes have colorful markings unlike the dull coloration of the pest species in the darkling beetle family.
Damage is similar to that caused by cutworms: seedlings are chewed off at the base and foliage may also be chewed. Damage usually begins at field edges as beetles tend to come in from weedy areas, alfalfa, or cover crops. Feeding occurs primarily in the evening and at night.
To prevent beetle invasions from an adjacent field, fill a ditch full of water to keep them out. If treatment is needed, a bait placed around the edges of the field will usually provide adequate control.
UC IPM Pest Management Guidelines: Cole Crops