How to Manage Pests
UC Pest Management Guidelines
Scientific Name: Hylephila phyleus
(Reviewed 9/09, updated 9/09, pesticides updated 12/16)
In this Guideline:
DESCRIPTION OF THE PEST
Adult fiery skippers closely resemble butterflies but have a hooked knob at the end of their antennae. They have orange or orange-brown wings and are commonly seen feeding on lantana blossoms. Adult females glue hemispherical eggs singly to the underside of grass leaves. Newly hatch larvae notch leaves. As they grow, they consume entire leaves. The larva is about 1 inch long and has what appears to be an oversized black head, a narrowed "neck" followed by a dark thoracic shield, and a greenish brown body color with a granulated texture. Larvae spin silk shelters in the thatch from the third instar on, and are not readily seen unless flushed out with a drench test.
Bermudagrass is preferred by fiery skippers, although they also feed on St. Augustinegrass, bentgrass, and occasionally other turfgrasses.
Skipper larvae feed from May through September. Damage appears as a 1- or 2-inch diameter round spot from which all the grass has been eaten by a single larva. If there is a large population, then these spots will coalesce into dead patches. Usually damage appears on turfgrass planted near flower beds, where adult skippers feed.
If skipper larvae are damaging turfgrass, dethatch the turfgrass to eliminate larval habitat. If monitoring indicates treatment is warranted, treatment choices include parasitic nematodes and Bacillus thuringiensis (Bt).
Larvae are attacked by parasitic braconid and ichneumonid wasps. The extensive soil or thatch contact of fiery skipper larvae may make Steinernema carpocapsae nematodes a valuable control measure, although this has not been tested. Bacillus thuringiensis subsp. kurstaki (Bt) may also be effective against fiery skipper, although more testing is needed to determine its efficacy for this purpose.
Monitoring and Treatment Decisions
Use the drench test to monitor this pest, see MONITORING AND TREATING INSECTS AND MITES. Five larvae per square yard on bentgrass greens and 15 per square yard in bermudagrass indicate treatment thresholds.
Mow the lawn and irrigate the site before applying insecticide, and do not mow or irrigate the turfgrass for at least 24 hours after treatment unless nematodes were applied, in which case apply a post-treatment irrigation. When Bt is applied, do not irrigate for 2 days after treatment.
UC IPM Pest Management Guidelines:
Insects and Mites
A. M. Sutherland, UC Statewide IPM Program, Alameda County
Acknowledgment for contributions to Insect and Mites:H. K. Kaya, Nematology, UC Davis
J. Hartin, UC Cooperative Extension, San Bernardino County
R. S. Cowles, Connecticut Agricultural Experiment Station, Windsor, CT
K. Kido, Entomology, UC Riverside
H. S. Costa, Entomology, UC Riverside
D. D. Giraud, UC Cooperative Extension, Humboldt/Del Norte counties