Keep dayliles pest- and disease-free
Daylilies are just about the ultimate flower. They adapt to a very wide growing area and different soil types, are easy to grow, low maintenance and drought tolerant and bloom spring through fall. Their colors range from almost white, yellow and orange to pink, red and purple. It is true the flower only lasts a day but the plant has many “scapes” (the stalk that contains the flower) ready to bloom tomorrow. Daylilies are a great flower for northwest Florida.
Daylilies are members of the lily family and in the genus Hemeorcallis. Do you know how they got their name? When botanists assign names to plants, they use Greek and Latin words that describe the plant. In this case, “hemero” is Greek for “day” and “callis” for beauty. Hence, “Beauty for a day”!
Most daylilies are virtually free of pests and usually require little or no pesticides. Sometimes, however they may become infested with aphids, thrips, spider mites and or grasshoppers. Thrips are one of the most serious pests. They are a gray-black insect about ¼ inch long. They damage immature stems and blooms, creating a bloom that is misshapen and discolored and also reducing the number of blooms. If the infestation becomes severe or a large number of plants become infected, chemical control may be necessary. There are several products you can apply, such as Orthene systemic insect control or any insecticide containing malathion. For those of you who don’t like all the chemicals, you may control these pests with insecticidal soaps.
Now, here comes the curve ball. New on the scene, an exotic rust species from Asia that infects daylilies has been discovered in Florida, Alabama, Georgia and South Carolina. Known as Daylily Rust, this could become a significant disease for all daylily growers.
Daylily Rust affects the foliage and starts on both sides of the leaves. The disease is very aggressive with pronounced, easy to identify symptoms. Once contaminated it only takes a few days for spores to germinate and symptoms appear. They will be bright yellow spots or streaks to smaller water soaked tan spots with darker borders. Later, raised pustules that are yellow-orange to rust colored will appear. Full development will take seven to14 days.
It is thought, but still undetermined, that planting Hostas in close proximity to daylilies increases the spread of the disease. Plant pathologists believe broad-spectrum contact and systemic fungicides will be effective against daylily rust. These includes Systhane, Strike, Banner, Maxx, Contrast and Heritage as a systemic control and Plantvax, Daconil, mancozeb, and Dithane as contact fungicides. Locally, Dithane and Daconil -- all rated for rusts -- are available. Fungicides other than those listed will likely not be effective. Avoid using just one fungicide in your spray program because the fungus will evolve resistant to that fungicide.
It has become more important than ever to purchase your daylilies only from state inspected and licensed growers and dealers. If you encounter suspicious and aggressive symptoms on the leaves of your daylilies, submit samples to your county extension agent’s office for diagnosis. If that is the case, institute a spray program immediately.
For more information about daylily rust, log on to The Plant Pathology Group’s Web site at the University of Florida or contact your local Extension Office. If you are interested in daylilies and would like to contact other daylily aficionados, join the American Hemerocallis Society (AHS) by contacting AHS Executive Secretary, P.O. Box 10, Dexter, GA 31019; and the Tallahassee Hemerocallis Society at 926 Rosemary Terrace, Tallahassee, FL 32303.
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