Denver Billbug – Sphenophorus cicatristriatus

Denver Billbug (Sphenophorus cicatristriatus) Common Name: Denver Billbug Latin Name: Sphenophorus cicatristriatus Appearance: The adult Denver billbug may grow to be between a third and a half of an inch in length, making it significantly longer than either the bluegrass billbug or the hunting billbug. This particular species of billbug may be distinguished from the other two species by virtue of its bigger size and the presence of distinguishing patterns on its wing coverings in the form of two lobes. Territory: Denver Billbug is found in North America Damages caused by Denver Billbug: Denver billbug causes fall and spring harm. Because billbug damage is often confused with white grub or sod webworm damage, illness, or plant stress, the affected turf should be thoroughly evaluated before making a management choice. Prior billbug infections in a turf area help with diagnosis. Billbug larvae crawl through grass stems, leaving sawdust-like plant detritus and feces. Infested stems discolor and snap easily at the top. Older larvae can kill a plant’s root system, generating drought-stressed grass. It turns brown and dies under billbug pressure. Adult billbugs eat grass stems and blades but inflict modest damage. Young grass seldom suffers billbug damage. Life history and habits: The Denver billbug can survive the winter as an adult, although it is more likely to do so as a mid-to-late-stage larva. Adult bluegrass and hunting billbugs emerge in mid- to late spring, depending on springtime temperatures and geographic region, with Denver billbug adults appearing a few weeks later (early May to June). Females of all three species lay their eggs in holes bitten into plant stems towards the crown after mating. Newly born larvae eat within stems for 2 to 3 weeks before moving to the crown and root zone of the plant, where they continue to feed on roots and subterranean stems. Billbug larvae often feed just beneath the thatch layer, but can be found as deep as 2 to 3 inches in the soil profile. When larval feeding is finished (about mid-July for bluegrass and hunting billbugs), pupation occurs in the soil or thatch. Adults emerge in late July, eat briefly, and then go to leaf litter in protective locations like as hedges, thick grass, and around homes to overwinter.