Recognizing The Signs of Billbug Activity
Look For Billbug Damage
Billbug larvae begin feeding on grass blades, hollowing out the stems, which causes grass to turn yellow. As the larvae mature, they will move down to the crown and thatch, and may also eat the roots and root system of the grass.Damaged grass will become discolored, and may appear in random spots throughout your yard, and grass will be easily pulled up. Extensive damage can kill grass.
Look For Frass That Resembles Sawdust
(To Confirm Billbug Infestation)
Billbug activity comes with another sign that can help differentiate billbug damage from other diseases, insect damage, etc. Billbug larvae produce frass, or excrement, that resembles sawdust. This moist, light brown material will be present in your turf near the crown, and will be a sign of billbug activity even if you do not see active billbug larvae.
Take Turf Samples
Take about a 6 x 6 inch sample in at least four areas of your yard. Cut at least two inches into your soil and pull back the turf/soil sample to look at the crown/root area. You should be able to see the larvae if they are present, and if there is more than 6 per sample, treatment is usually necessary.