How are moths and sod webworms connected might you ask? Great question! Much like a caterpillar turns into a butterfly, the webworm turns into a moth. How does the moth create the brown spots in the lawn? To be precise, the moth doesn't actually cause the turf damage, because it's larva does- the webworm. Webworms chew the grass down to the roots as it's primary source of food, causing a similar effect on the lawn as if it were scalped with a mower. The chewed or affected areas typically look like brown circular spots in the lawn that are much shorter than the other parts of the yard, and they typically grow overnight, because that's when the webworms are most active. The round pattern comes from the moth's eggs being laid in one place and the webworms eating out from that initial hatching.
Webworms are known for attacking new sod (hence the name 'sod webworm') due to their high levels of nitrogen in the turf from the sod farms requiring high growth rates and using large amounts of fertilizer. They're also known for attacking shaded areas of lawns due to the moths residing in the trees above the lawn.
Although Zoysia Turfgrass is known for being chinch bug resistant, it is proving to be a food source for webworms. Although we see more infestations in St. Augustine lawns, newer Zoysia lawns have certainly had their share of Webworm damage this year, too.
Many clients have asked about prevenative treatments, but the sad news is that prevention has little to do with insecticide and more to do with limiting the amount of quick release nitrogen getting on the lawn as it gets later in season. Due to the amount of rainfall in our area and the lack of residual insecticides that work on webworm populations, much of the control is after their infestation is noticed. This is why it's extremely important to be on our lawn care program, as it covers not only limiting the fertilization of nitrogen to help prevent webworms, but also treating the webworm infestation when it occurs, and as many follow-up treatments as your lawn needs.
Have you noticed your lawn turning brown? or noticed moths flying when you walk through your lawn in the morning? Those are warning signs that the Tropical Sod Webworm is about to feast on your grass.
If you think your Gainesville lawn has pest concerns, please don't hesitate to call us at 378-LAWN or fill out our online request form. We want to help in any way we can.