It’s that spooky time of the year again when the creepy-crawly caterpillars come out to turn your lawns into a horror movie. Sod Webworms and Cutworms – they’re not really worms but moth larvae or caterpillars. But like classic horror movie monsters, these caterpillars are usually not seen during the day. They feed at night.
Sod Webworms cause the most damage when they are newly hatched from their eggs when they feed on the foliage of turfgrass. Damage is often seen as a small area of leaves that are yellow to brown. In closely-mowed turf, symptoms will appear more quickly and prominently.
Cutworms get their name from their habit of “cutting” off a seedling at ground level by chewing through the stem. Some species are subterranean and eat roots. One of the most common garden pests is the variegated cutworm, which can defoliate entire gardens and fields in a matter of days.
So how do we combat these nocturnal marauders?
Sod Webworms, Cutworms, and even the day-walking Army Worms (above) are easily controlled by most liquid insecticides approved for turfgrass: bifenthrin, malathion or any of the synthetic pyrethroids or carbamates out there.
If you’re looking for a 100% organic solution: bacillus thuringiensis, otherwise known as Liquid Bt, is a natural bacterium that only targets caterpillars. It’s a great addition to the liquid insecticide regimen. Any Sod Webworm, Cutworm or Army Worm that bites into a Bt-treated blade of grass should react like Dracula drinking holy water.
It takes more than one treatment to eradicate these harmful caterpillars from your lawn. This is because the insecticides target only the larvae as they crawl along the grass. It’s harder to get the eggs since they are stationary, and it’s difficult to get the moths (that lay the eggs which become the caterpillars) as they fly about. By going back over the treated areas again, the insecticide has a chance to get the newly-hatched eggs and further deters moths from landing in the area to start the cycle anew.
We recommend treating the affected area 3-4 times in a 21-day period to make sure the Worms don’t rise from their graves.
If you’ve walked through your yard and had tiny moths scatter up around your feet, that’s a likely signal that these caterpillars are on their way. But if you treat your lawn using the control methods listed above, you’ll get control of them before they can turn your lawn into Blight of the Living Dead.
Contact us at Sterling Design & Landscape Resources to talk with one of our experienced landscape designers. We would love to help you with your fall gardening needs.