Pensacola News Journal

For: Immediate Release

By: Daniel E. Mullins

Extension Horticulture Agent

Santa Rosa County

Daylily Disease Alert

The daylily, that hardy, dependable and colorful perennial has encountered a problem. Daylily rust, a fungus disease, is being reported daily in our area.

This rust fungus, which has been confirmed as Puccinia hemerocallidis causes raised yellow-orange to rusty brown pustules on the underside of the leaf. On the more susceptible varieties the entire affected leaf dies, while in more resistant varieties the lesion may be no more than a fleck.

Daylily rust was first found in a southeastern nursery during the summer of 2000. Prior to that time, it had only been reported in Asia.

This disease is very aggressive on the variety, “Pardon Me,” and there are

varying degrees of resistance and susceptibility among the many daylily varieties.

The disease is spread by airborne spores and through the movement of plants. Following the inoculation of leaves, infection occurs within 2 to 3 days. This disease spreads quickly once present. All known infections have been found on the leaves. Presently, it is not known if infection is occurring on the tubers.

Control

Control of daylily rust disease will require a combination of sanitation and the regular application of approved fungicides. First, remove and destroy infected foliage from plants. Be thorough, because if any infected leaves are left on plants, they will continue to be a source of infection by producing spores.

Fungicides for the control of daylily rust must be selected carefully. There are two categories of recommended fungicides, and one from each category should be rotated, and applied on a 7 to 14 day schedule. Category 1 includes fungicides with the following active ingredients: Propiconazole, Azoxystrobin, Flutolanil and Myclobutanil. Category 2 includes Chlorothalonil and Mancozeb.

Finding a fungicide from each category might require some extra effort. Nurseries and pest control operators can readily obtain these products because they purchase from specialty suppliers and in larger package sizes than the homeowner or hobbyist.

When searching for these fungicides at the local garden center, check the active ingredient on the label. The product name on the front of the container might be something generic such as “All Purpose Fungicide” or “Lawn and Ornamental” fungicide, yet contain one of the products listed above. Also, make certain that the product is labeled for use on daylilies.

This disease is new to the northern Gulf Coast, so we don’t know the long- term effects on daylilies. More detailed information is available from several sources. Web users go to http://www.aphis.usda.gov/npb/daylily.html or http://doacs.state.fl.us/~pi/enpp/pathology/daylily-rust.html.

These sites also provide lists of varieties and their relative susceptibility.

The word about daylily rust is traveling fast among gardeners who favor this plant. Naturally, they are sad be experiencing problems with a plant that has been almost trouble free in the past. We do however have some knowledge of the disease and tools with which to work toward controlling it.