Wheat Flea Beetle

Northwestern Colorado wheat fields support an insect pest that is apparently unique to that area.  The wheat flea beetle, Chaetocnema subconvexa R. White 1996 is present in most winter and spring wheat in Moffat and Routt Counties.  This insect is unknown from wheat grown in other areas. 

The flea beetle was first found during insect surveys conducted in the early 1990’s. It is easily found in sweep net samples and can be abundant at times, especially in spring planted wheat.  Its impact on wheat yield and quality remains unknown.
Wheat Flea Beetle

The adult beetle is small, about 2 mm in length and shiny bluish/black in color. They are very active insects, jumping to a foot or more in height, giving name to the name flea beetle. Adult flea beetles are present in varying numbers throughout the spring and summer months.

The egg and pupal stages are unknown.

Larvae are creamy white with lines of brownish spots outlining the thoractic and abdominal segments.  They have three pairs of true legs. Larvae feed within developing secondary and tertiary tillers deep within the growing plant. These tillers are typically near ground level. We have observed only one infested tiller per plant in the limited number of damaged plants we have inspected.

WFB WFB larvae Wheat Flea Beetle Larvae

Infested tillers are killed, but the impact of the beetle on wheat yield is unknown.  It is very possible that plants compensate for lost tillers by putting those extra growth resources into surviving tillers.


Chaetocnema subconvexa has been observed damaging a seed production field of blue wild rye, Elymus glaucus near Meeker Colorado (Rio Blanco County) and it is probable that they feed on several species of related wheatgrass and wildrye.

WFB


This page was updated on January 30, 2015