Linda Benedict, Holcomb, Gordon E., Owings, Allen D.
Allen D. Owings and Gordon E. Holcomb
In the summer of 2000, daylily rust was reported for the first time in the United States. It has since spread across most of the country and continues to present problems for home gardeners, commercial landscapers and daylily growers.
The LSU AgCenter and Louisiana Department of Agriculture and Forestry offer some guidelines first recommended by the Florida Department of Agriculture and Consumer Services and based on ongoing daylily rust research at the University of Georgia.
Infected plants should be cut back to an inch or less and treated repeatedly with labeled fungicides. Foliage from infected plants should be removed and destroyed. Infected plants should be isolated from other daylily beds and varieties. Fungicides recommended (for prevention more than control) are Systhane, Banner Maxx, Contrast and Heritage. All are systemic materials. Others to consider are Strike (systemic) and Dithane (protectant/contact). Most broad-spectrum contact and systemic fungicides may be somewhat effective and may be useful in combination; however, experience has shown that effectiveness is limited.
Home gardeners and growers should make note of varieties showing rust-like symptoms because these varieties may be susceptible. Research in several states is beginning to show major differences in susceptibility among varieties. It is now becoming commonplace for growers to remove moderately and highly susceptible varieties from production. Daylily rust infection occurs two to three days after leaf inoculation. The disease spreads quickly in nurseries and may kill the foliage. All known infections have been on the foliage and flower stalks.
Allen D. Owings, Professor, Department of Horticulture, and Gorden E. Holcomb, Professor, Department of Plant Pathology
(This article appeared in the spring 2005 issue of Louisiana Agriculture.)
The LSU AgCenter and the LSU College of Agriculture