Sod Web worms are the larval stage of a moth. The live mostly on the surface of your
lawn after the eggs hatch out. During hot days, they live in the shade of the grass blades, on the bottom of the blades and they eat mostly at night and during cooler, clowdy weather. They eat your lawn. Yum, Yum.
Treating them isn't too hard of a thing to do but, timing is important. They can be treated using nematodes and neem oil. However, you'll get your best results if you apply these products in the evening, after the sun goes down. The reason why is, the moth that lays the eggs flies over your lawn this time of the day to spray it with eggs, and, the worms themselves come out to eat and expose themselves to what you're doing. They can avoid some damage during the day just by hiding under the blades of grass.
So, get some neamtodes and apply them according to the instructions that come with them. Put them down right after sunset and
water the lawn afterwards.
After a couple of days, s[ray the lawn with neem oil, mixed as per instructions and do that at the same time of day.
Depending on the level of infestation, you may want to apply the nematodes, once, twice or even three times a year. Neem oil can be used as often as you need to. Neem oil will keep the flys, mosquitoes and other pain in the neck bugs away too. Neem oil will keep
bees away too so, avoid using it around fruiting plants and vegetables during bloom stage.
You can read more about these things here:
http://www.dirtworks.net/Neem-Oil.html and here:
http://www.dirtworks.net/Biologicals.html Good Luck Mate, John