Notice any little white moths flying around your grass? Does you lawn look like it’s being grazed on by a heard of sheep? Congratulations! You have sod webworm, yet another one of those annoying pests that invade Florida lawns this time of year.
The moths themselves do NOT chew on the grass and they are also not harming your shrubs or flowers. However, these moths lay eggs on the blades of grass and the resulting larva nibble. If you suspect sod webworm, take a close look at the grass blades. They will look as if something is chewing on the sides.
Fortunately, sod webworm can be easily controlled if caught in time, and the damage the caterpillars inflict does not have to cause permanent harm to your lawn. There are several products available that can control the caterpillars. Bacillus thuricide (BT), a bacteria that is considered organic, kill the larva within 24 hours when sprayed or dusted on the lawn. However, repeat applications might be necessary throughout the summer. Products containing spinosad, another bacteria, will also kill the caterpillars within two to three days and, in addition, kills other chewing pests like thrips. Pyrethrin and permethrin products also kill sod webworm but will probably have to be re-applied at intervals throughout the summer. Perhaps the best choice, especially to prevent sod webworm in the first place, is a systemic insecticide containing imidacloprid (like Hi-Yield Grub Free Zone granules) which will last all season or one of the other new systemic lawn pest granules that are only applied twice a year.
A word of caution: Both thuricide and spinosad products kill ALL caterpillars, both good and bad, so if you have a butterfly garden be sparing with their use.