Sod Webworms are Active in Pinellas County and Causing Damage to St Augustine Grass Lawns


By Rick Orr 04/24/2020
Sod webworm damage done to a St Augustine lawn
Sod webworm damage is circular in appearance, can be any size from a few inches to an entire lawn. 

Sod Webworm Biology

The sod webworm is the larva of those little tan moths that flit about the lawn when disturbed as you walk in the lawn. The moths are a nuisance but harmless and there is no effective control for the moth. The adult moths lay eggs in the lawn with the best chance for survival of eggs and larvae - concentrating eggs in prime areas of the lawn.

Most Active May - October

In Pinellas County, lawn moths are most active laying eggs from May through October. During these times, the egg-laying and hatching is constant and the population can expand logarithmically in prime areas of the lawn. A few sod webworms here and there are not a problem. However, when the sod webworm population explodes, they can mow your lawn for you.

The Damage

Close up of sod webworm damage with sod webworm, frasse and chewed leaves

Sod webworm damage is circular in appearance, can be any size from a few inches to an entire lawn, and often a distinct grey or tannish color. The most distinct symptom is the lawn is shorter in the damaged areas – this is because the sod webworms are cutting down the St Augustine grass.

Sod webworms feed on St Augustine grass leaves. However, instead of eating the entire leaf, they chew across the leaf near the stem and move on to the next leaf. This gives the area a “mowed” appearance. Then the leaf that has been cut turns grey to tannish brown giving the damaged area a distinct color.

If you look closely at the damaged area you will see the cut marks on leaves and stems where the sod webworm is feeding. Looking further into the canopy you’ll find the little green caterpillars curled up at the soil surface.

No Need to Panic over Lawn Moths or Sod Webworms

No need to panic over the moths or sod webworms – a few sod webworms will not harm. In areas where the population is high, they can damage the lawn, however, St Augustine will fully recover from sod webworm damage if treated. Left untreated, the sod webworms will feed on stems and roots and destroy the lawn.

For the DIY

The best treatment is to spray the damaged area with an insecticide – just about any will do – and let the sod webworms feed on the treated grass overnight. Within a week the grass will return to a normal appearance. Treat as often as you see damage.

For APL Customers

We have been treating for sod webworms since February – so no need to do anything. However, should you see any suspicious areas, feel free to call and I’ll check it out for free.

Rick Orr Owner-Operator APL Pest Control/Creator of ILOVETURF.COM
APL Pest Control

Since 1995, Rick Orr has worked in Pinellas County providing turf management and pest control. Rick Orr is a graduate of VA Tech in Agronomy (Turf Ecology) and the creator of

Since graduating from VA Tech in 1979, Rick worked in the green industry, mostly with golf courses, resorts, and large communities. Rick has obtained certifications in arboriculture, landscape contractor, and irrigation contractor, and taught Environmental Horticulture at St Petersburg College. 

Currently, Rick is the owner and operator of APL Pest Control. APL Pest Control provides lawn care and pest control for all of Pinellas County.

To learn more about APL Pest Control CLICK HERE

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