Turf Caterpillars & Moths In The Landscape |
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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! My friend told me that they will kill my lawn!
The sudden invasion of thousands of white moths in the landscape is a common concern! Every spring through summer, we get many phone calls from concerned homeowners and landscapers 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 Webworms and Armyworms caterpillars can - and often do - damage lawns. They are treatable and manageable!
Sod Webworm Adult Moth
Sod Webworms and Armyworms moths hatch out of pupa in the soil in mid-spring through summer. 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 landscape plants. In fact, the moths don't have the mouthparts necessary to feed on your grass or landscape 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.
There is no good way to prevent
adult moths from flying into your lawn
or shrubs, or to treat for them once they fly in.
adult moths from flying into your lawn
or shrubs, or to treat for them once they fly in.
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.
New St. Augustinegrass Sod Severely-Damaged By Sod Webworms
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 looks like green pellets. Sod Webworms frass is much smaller than Armyworms frass. Pictures below are Sod Webworms chewing damage (left) and Armyworms frass (right).
Sod Webworms Chewing Damage To St. Augustinegrass
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Armyworm Frass (Light Green Disks)
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Since we expect Sod Webworms and Armyworms activity in spring through summer, we pay close attention to these caterpillars and the damage that they cause. If we find chewing damage and/or caterpillar 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.