Help! These little white moths are everywhere! They're in my lawn, my shrubs, and my trees! Some are even coming inside my home! There are thousands of them!
The sudden invasion of thousands of white moths in the landscape is a common concern! Every spring, we get many phone calls from concerned homeowners about these invaders. The internet is full of information about these moths - some accurate, some not! Lets gets the facts straight - here we go!
Sod Webworm adult moth. Photo credit: University of Florida This time of year, Sod Webworms and Armyworms moths hatch out of pupa in the soil. The moths hide in grass and shrubs. If you walk through your lawn or brush against shrubs, you may see Sod Webworms moths fly out - sometimes by the thousands! Armyworms moths are seen less frequently. While this "moths explosion" may seem traumatic, the moths are completely harmless. They do not feed on the grass or plants. In fact, the moths don't have the mouthparts necessary to feed on your grass or plants. They may sometimes visit flowers for nectar. Since the moths do not feed on the grass, we typically do not spray for them with insecticides.
Fall Sod Webworm Caterpillar So why do these moths hang out in the lawn and shrubs? Well, the moths lay eggs on the grass blades. 2-3 weeks later, eggs hatch into caterpillars, which feed on the grass. St. Augustinegrass, Zoysiagrass, and Bermudagrass are the caterpillars' favorite food.
Severe Sod Webworms injury to St. Augustinegrass Often, Sod Webworms and Armyworms injury is limited to minor chewing. But many times the caterpillars are so numerous and feed so quickly that the grass is chewed down to the stems within just a few days. This can be disastrous to the lawn.
Newly laid sod is particularly susceptible to injury. This is one of the reasons that we recommend systemic insecticide application to newly-installed sod.
Newly laid sod is particularly susceptible to injury. This is one of the reasons that we recommend systemic insecticide application to newly-installed sod.
The best way to diagnose caterpillar activity is by looking for the chew marks on the grass blades, observing the caterpillars feeding, and finding caterpillar frass (poop) in the grass. Fresh frass will be green pellets. Sod Webworms frass is much smaller than Armyworms frass. Pictures below are Sod Webworms chewing damage (left) and Armyworms frass (right).
Since we expect Sod Webworms and Armyworms activity this time of year, we pay close attention to these caterpillars. If we find activity, we treat the lawn with effective insecticides.
To recap - the moths that you are seeing flying around in your landscape are harmless. Even if there are thousands of them. The moths do lay eggs, which will eventually hatch into caterpillars. The caterpillars primarily feed on St. Augustinegrass, Zoysiagrass, and Bermudagrass. While we monitor for activity on every service, we ask that you call our office if you notice chew marks on your lawn.
For more information about Sod Webworms from the University of Florida, please click here.
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