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Bluegrass Billbugs (Sphenophorus parvulus)

Denver, CO adult Bluegrass Billbugs are blackish gray in color with a hard body that is about 3/16" (5 mm) in size. They can be distinguished by their long snout-like forehead. The adults survive in the thatch layer during the growing season. The adults may cause some damage to the lawn by chewing holes in grass blades; however, the damage inflicted is minor compared to that of the larvae. During the spring and fall the adults may frequently be spotted traveling along sidewalks and driveways.

Bluegrass Billbugs Larvae


Bluegrass Billbug damage frequently resembles drought symptoms. Large areas of your lawn may appear wilted with a yellowish brown color, however it will not respond to watering. Your Denver, CO Weed Man can make a proper diagnosis.

Bluegrass Billbugs do the majority of damage while in their larvae stage. Larvae are legless with a fat whitish body and brown head. They feed on the grass roots and stems, often cutting the roots and stems of the grass off, allowing the plant to be pulled up easily.

Life Cycle

To control an insect population we must first understand its habits and life cycle. Bluegrass Billbugs require one year to complete their life cycle. They survive the winter as adults living in protected areas such as gardens. Early in the spring they emerge wandering about the lawn. By late June the females begin depositing their eggs in the lawn. The eggs begin hatching in about two weeks. They feed on the grass plants while moving into the soil. Serious damage may occur in the summer. If the problem is ignored, the brown patches will get larger and damaged areas will then fill in with weeds or crabgrass. The best time to control the Bluegrass Billbugs is when they are very young (June-July) before you are faced with severe damage. Why wait? By early fall they begin to transform into adults to over winter. While in the adult stage they are extremely difficult to control.

Bluegrass Billbug Lifecycle


Your Weed Man Denver, CO is a trained specialist. He or she can recognize the difference between a simple drought problem and a Bluegrass Billbug infestation. Your Weed Man uses materials that are applied carefully and precisely at the correct time to be most effective in controlling this lawn pest. Your Weed Man Denver, CO professional needs YOUR HELP. Call us and we will inspect your property FREE OF CHARGE! If you do have Bluegrass Billbugs, we can protect your investment in your property by promptly treating the problem. If your yellow patches are in fact due to lack of water, we can advise you on correct watering procedures.