The image above is an example of evidence of sod web worms. In extreme cases, you may notice webs throughout your entire lawn. It is very important to treat for them before its too late.
The larvae of web worms attack bluegrass and many other species of grass. Please note that "sod" does not confine this species to attacking fresh sod.
The first signs of sod web worm feeding are found in spring. The results to their chewing leaves the grass and leaves behind in thin patches of shorter grass. When the insect grows it will cause larger areas of brown sod. The damage is most common in sunny and dry parts of your lawn. Most commonly along curb edges and driveways.
The worst evidence is seen in late July and August and may be mistaken for drought stressed grass that has entered summer dormancy. You can determine it is web worm lawn damage by digging into the thatch and finding the silk lined tunnels. A home remedy to see if you have a web worm problem is to mix two tablespoons of liquid dish soap with two gallons of water and soak an area of the lawn. You should notice that within minutes the tan spotted worms come to the surface.
Web worm moths lay eggs in spring. Females can lay 60 eggs per night and eggs hatch in just a week. The complete cycle from larvae to adult takes six to ten weeks and the insects may produce several generations per season. The latest generation overwinters in tunnels in the soil. Growing larva house themselves in silk lined tunnels in thatch, where they feed on the nearby green blades.
Sod Web worm control must focus on the larva, not the adult moths. There are several species of sod web worms, some of which only have one generation in mid to late summer and do not cause much damage. The first generation of larvae that emerge in the spring are found to cause the most damage to your lawn. This is why we do applications in the spring to catch the first generation right away which limits the most damage.