To determine if you need to implement control measures, mix 1 tsp. Pour this mixture over a one square foot area of lawn. Repeat in several spots and wait 10 minutes. Xen Tari, is a water dispersable granule that is applied with conventional spray applicators. The sod webworm is killed after the larvae ingest the Bt insecticide.
Bt products are available in most home garden centers and from mail order suppliers.
However, these insecticides are of somewhat higher toxicity compared to Bt, and will also kill the beneficial organisms that contribute to soil fertility and long-term management of sod webworms and other lawn pests. Read and follow all label instructions when using any pesticide, whether natural or synthetic. Turfgrass Insects in Colorado and Northern New Mexico . Handbook of Integrated Pest Management for Turf and Ornamentals . Leslie, A.R., ed.