Sod Web Worms And The Damage They Cause

What to do this week
By Mark Govan, Host “Florida Gardening” on 970WFLA

ABC Pest Control Inc. FloridaSod Web Worms And The Damage They Cause

Ever since our afternoon rains returned with more frequency, our landscapes, including our turf grass are growing very quickly. Plants have been pushing out new growth and our lawns now require mowing weekly. This abundance of fresh growth has also caught the attention of lawn pests such as the Tropical Sod-Web Worm and the Army Worm. You may have seen the adult stage of these pests, a moth, while walking on your grass. Moths tend to frequent shady areas of your property and sometimes hundreds of them may gather. In this article, I would like to share my experience in detecting these insects and controlling them. Let’s get started!

Knowing you have a problem is half of the battle. If you see that you have hundreds of moths in your lawn, each producing up to one thousand eggs, then you should start thinking about applying a control product. Even though there is no control for the moth or adult stage of this pest, the eggs that have been deposited on your lawn are getting ready to hatch. When they do, the feeding frenzy will begin. Learning the life cycle of this pest will help you to control them before damage is done.

Even though their name suggests these pests are worms, they really are a caterpillar. Turf caterpillars have a complete life cycle, which starts out as an egg. In about three days, the eggs hatch into a larva or caterpillar. The young caterpillars start feeding immediately upon hatching from their tiny egg capsules and grow quickly. This growth stage lasts approximately eighteen days. Damage to the lawn occurs during this time. Look closely at the blades of grass in your yard. The edges on the grass blade will be chewed off resembling a corn cob with several bites taken out of it. As the infestation continues, wide areas of turf grass will be eaten. From the street, you may think that your Lawn Company only cut half of your grass. Lawns left untreated at this point will soon be decimated.

Most people will not see the damage until after it occurs. This is because the heaviest damage occurs during the night when the caterpillars are most active. Even though the army worm is much larger than the sod web worm, they are rarely seen. Army worms can grow up to an inch and a half long, while the sod web worm grows to a maximum of three-quarters of an inch. You may think this size difference will give the army worm the dominance in the damage they can do, but I have seen more damage to lawns caused by sod web worms than by army worms.

The best way to control an infestation is to apply a liquid insecticide such as Bifenthrin. Bifenthrin will kill the young larvae as they begin to feed. By using a liquid product, you can treat all the blades of grass, giving you better control of the larvae as they feed. A second application may be necessary in fifteen to thirty days to break the life cycle and kill any additional eggs that have hatched. Although Bifenthrin is one of the preferred products I like to use, there are a couple of organic choices you can also use to control these pests.

Dipel and Thuricide contain the active ingredient, Bacillus thuringiensis. This naturally-occurring organism only kills caterpillars. Many organic gardeners prefer these types of products, which are selective in the insects they kill. Once the caterpillar ingests one of these products, the bacteria begin to reproduce very rapidly in the caterpillar’s stomach eventually paralyzing the caterpillar’s digestive tract and stopping the caterpillar from feeding. Death occurs within one to five days. If you choose to use one of these products, then you need to be aware that they must be ingested by the caterpillar in order to work, and they must be re-applied to the turf grass if rainfall occurs.

Monitor your lawn for moths and look for chew marks or bites along the edges of your blades of grass. Select the products that work best for your lifestyle and landscape and always read the label before applying any product. Enjoy your landscape and remember, without plants, we would not be here!

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