How to Manage Pests
UC Pest Management Guidelines
Scientific names: Blapstinus spp., Coelus spp., and others
(Reviewed 10/14, updated 10/14, corrected 8/16)
In this Guideline:
DESCRIPTION OF THE PESTS
Darkling beetle adults range from 1/8 to 1/2 inches (3 to 6 mm) long and vary from black or bluish black to rusty brown. Darkling beetles may be hidden by dust or a thin layer of soil. Cylindrical, wirewormlike, soil-inhabiting larvae are light yellow to dark brown and range from 1/33 to 1/3 inch (0.8–8 mm) in length. They are often referred to as false wireworms.
Do not confuse darkling beetles (Tenebrionidae) with predatory ground beetles (Carabidae), which prey on various soil dwelling pests. Darkling beetles generally have clubbed antennae whereas predatory ground beetles do not.
Adult darkling beetles can become a pest on young pistachio trees when they climb up the rootstock and eat the Kerman bud three to four weeks after budding. They can also damage emerging Kerman shoots during the spring following their first dormancy.
Avoid discing weeds within the orchard or adjacent fields at the time of budding. Discing in crops like alfalfa has been known to promote migrations of darkling beetles. Monitor for darkling beetles during the first month after budding. If an unacceptable number of buds are being consumed, consider treating the orchard with a carbamate-based bait. It may also be possible to avoid damage by wrapping the trunk with double-sided sticky tape to prevent beetles from crawling up the rootstock.
UC IPM Pest Management Guidelines:
Insects and Mites
D. R. Haviland, UC Cooperative Extension, Kern County