Caterpillar in My Lawn, Is it the Sod Webworm?
Q: Actually, I have several questions regarding a “worm” I found crawling through my St. Augustine grass. Is this “worm” beneficial or harmful to my turf? Is this a Tropical Sodworm caterpillar? Should I expect my St Augustine grass to recover after I get rid of the caterpillars? Is there any way to prevent these caterpillars going forward?
A: This is not the tropical sod webworm. It appears to be a armyworm. There are many caterpillars that like turfgrass. This is a caterpillar of a moth that will feed on your turf and many other plants in the landscape. It can be hand picked and destroyed to ensure control. The sod webworm is much, much smaller and although it can be hand picked too, it is very difficult to see in the grass. It is less than ½ inch long.
If the grass damage you see is caused by caterpillars, then the grass should recover. However, something else may be causing the decline but controlling the caterpillars will help.
The adult moths of these caterpillars can fly in any day or night to lay eggs, there is no real way to prevent them. Additionally, insecticide are not meant to prevent insects but to control and kill them once they are on the property. Save your money and use and insecticide once you have seen them and identified them correctly so you can use the correct pesticide. Read and follow all directions on pesticide labels for your safety and the safety of the environment.
See this EDIS publication for more information about Caterpillars in the Lawn.