Color: Larvae have a brown head but can display various body colorations, including beige, grey, brown or green
Size: larvae are covered with dark, circular spots and coarse hairs. Full-grown larvae range in size from ⅝-1″, but most are ¾″.
Sod webworms overwinter as immature larvae in silk-lined chambers in the thatch layer. As temperatures begin to warm in the spring, larvae become active and resume feeding on turf grass blades at night. During the day, larvae will seek refuge in the thatch layer.
Sod webworms overwinter as immature larvae in silk-lined chambers in the thatch layer. As temperatures begin to warm in the spring, larvae become active and resume feeding on turf grass blades at night. During the day, larvae will seek refuge in the thatch layer. Larvae are more obvious and curl into a ball when disturbed.
Adults are also nocturnal and can be seen flying low over turf grass and feeding on plant dew. Mated females will drop eggs over the turf grass;
One way to flush larvae from the thatch layer is to pour soapy water (2 tablespoons liquid dishwashing detergent into 2 gallons of water) over a 1ft2 area on the turf grass and watch for larvae to surface.
Caterpillars feed during the night on turf grasses. Injured grass blades initially appear notched and ragged as tissues are removed from the edges until the entire leaf is consumed. Injured turf is usually spotty within a lawn, but damaged areas enlarge as caterpillars migrate in search of more food. Heavily injured turf grass may die but usually recovers. St. Augustine grass recovers more slowly than Bermuda grass.
Sod webworms prefer to feed on turf grass, being the ideal food source. Larvae are the damaging life stage and clip turf grass blades off just above the crown. Initially, sod webworm damage begins as a general thinning to a small area, followed by the presence of obvious brown patches. Severe infestations can cause large irregular patches throughout a lawn. Because sod webworms are feeding on aboveground plant tissue, the roots remain intact.
- Rake up thick thatch and destroy it. This reduces the number of webworm burrows. Try drenching infested patches with a soap solution. As webworm wriggle to the surface, collect them with a leaf rake and drop them into a bucket of soapy water
- Parasitic soil nematodes are effective against webworms. These microscopic nematodes are sprayed on irrigated turf and lightly watered in. There are two types of parasitic nematodes available commercially. One type, Heterorhabditis spp., is very aggressive, works in cool or warm soils, and inhabits soil down to 15 cm. The other type, Steinernema spp., is less aggressive, works best in warm soils, and stays in the top 5 cm of soil.
- The microbial product Bt (Bacillus thuringiensis) can be used to control webworm. This naturally occurring bacterium acts as a stomach poison when it is eaten by caterpillars, but does not damage other insects.
Manufacturer Recommended Products And Treatment For Sod Web Worm Control
Pests need food, water, and shelter. Often the problem may be solved just by removing these key items. Before even thinking about chemical pest control, it is important to be aware of
Conducive Condition | Recommendation | |
1 | Tree branches on house | Keep tree branches away from house to reduce pest access |
2 | Firewood next to foundation | Keep firewood away from house to reduce pest harborage |
3 | Debris on crawlspace/next to foundation | Remove wood debris to reduce termite ha rborage area |
4 | Excessive plant cover, stump, etc. | Providing spacing between plant cover and structure |
5 | Soil above the foundation Ii ne | Keep soil below top of foundation to reduce harbo rage areas |
6 | Wood-to-ground contact | Keep soil from touching wood to eliminate termite access |
7 | Debris on roof/full gutter | Keep gutter & roof free of debris to reduce insect harborage |
8 | Standi ng water near/under structure | Eliminate standing water to reduce pest harbo rage |
9 | Mo isture problem under structure | Increase ventilation to reduce pest harbo rage area |
10 | Openi ngs at plumbi ng & electronics | Seal opening to reduce pest access |
11 | Excessive gaps at windows/doors | Seal gaps to reduce pest access |
12 | Lea ky plumb ing fixtures | Repair to reduce moisture for pests |
13 | Keep garbage cans covered | Covered to reduce attraction of insects of vertebrate pests |
14 | Mo isture damage wood | Repair rotten or damaged wood to reduce insect harborage |
15 | Grocery bags stored improperly | Seal paper sacks in containers to reduce i nsect ha rborage areas |
16 | Pet food unsealed or left out | Keep pet food in sealed containers and unavailable to pests |
17 | Excessive storage conditions | Keep storage areas uncluttered and manageable |
18 | Debris below kick plates | Remove kick plates to reduce rodent harborage |