Lets talk about an issue common this time of year, Sod Webworms. Ive been getting a lot of service calls, and seeing them a lot on my normal services lately. A lot more than I have in past years. You can see them throughout the year given the right conditions, but you will see the most activity from July-August.
Sod webworms are the result of moths laying their eggs in the lawn. These eggs turn to larvae, then pupate in early summer when they begin feeding on the lawn. Many people will see moths in their lawn and automatically assume its Sod Webworms. Even though this could be a sign, its not a for sure thing. There are a lot of different types of moths out there laying eggs for things other than Sod Webworms that won’t damage the turf.
When inspecting an area of the lawn where Sod Webworms are present, you will see green fecal pellets called frass, pictured above. You will also see the worms, which have a green color, also pictured above. They get to be 1/2″ – 3/4″ long, so they are fairly easy to see when inspecting. One way to inspect and area would be to take a couple gallons of water and add dish soap to the area. This will disturb the worms sending them to the top to breathe.
The Sod Webworms, are chewing the grass blades, so it will be easy to see the damage, From afar it will look like an area of the grass was mowed lower than the rest. Looking closer you will be able to see the chew marks on the grass blades. The area will also start turning a little brown from the stress as well. Since its just the grass blades being affected, the damage area will grow back in after a few mowings once the Sod Webworms are gone.
Sod Webworms are pretty simple to control. There are many different insecticides that will take them out. My preferred insecticide is any with the ingredient Bifenthrin since it is useful in controlling many other types of insects as well. Because Sod Webworms eat at night, its best to treat for them late in the afternoon to ensure the product comes in contact with them. As always, remember, THE LABEL IS THE LAW. When using any products make sure to read the label to make sure the problem you are trying to treat is listed on there. I recommend contacting your local Lawn Care Professional to resolve any of your lawn or shrub issues. They will have to proper products and equipment, as well as knowledge, to effectively take care of any of your issues.