Daylily Rust Puccinia hemerocallidis in the United States - PowerPoint PPT Presentation

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Daylily Rust Puccinia hemerocallidis in the United States
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Daylily Rust Puccinia hemerocallidis in the United States

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    1. Daylily Rust (Puccinia hemerocallidis) in the United States Jean L. Williams-Woodward and James W. Buck University of Georgia

    2. Leaf Rust on Daylily Identified in Georgia in August 2000 on cv. Pardon Me brokered from Costa Rica

    3. Daylily rust symptoms Cultivars vary in susceptibility Symptoms vary with cultivar

    4. Daylily Rust in the United States Identified in 25 states on numerous cultivars AL, AR, CA, CN, FL, GA, IN, IL, IA, KS, KY, LA, MD, MO, MN, MS, NC, NY, OH, PA, TN, TX, SC, WI, VA Spread mostly through the sale or trading of infected plants Infected plants should be removed or the foliage cut off at the soil line and re-growth treated with fungicides to reduce rust re-infection and spread.

    5. Puccinia hemerocallidis Thuem. Urediniospores are globose to ellipsoid and average 22 ? 19 ?m. Teliospores are 2-celled and average 46 ? 18 ?m. 1-celled teliospores (mesospores) produced that average 38 ? 16 ?m.

    6. Puccinia hemerocallidis Thuem. Native to Asia China, Japan, Korea, Taiwan, Russia First described in 1880 Synonyms: Uredo hostae Puccinia hostae Puccinia funkiae

    7. Patrinia scabiosifolia (Golden Valerian) P. gibbosa P. triloba P. villosa P. rupestris Uredinial/telial host: Daylily (Hemerocallidaceae) and Hosta (Liliaceae)???? Aecial host: Patrinia spp. (Valerianaceae)

    8. Is Hosta a Host? P. hemerocallidis described on daylily and Hosta spp. Urediniospores from daylily did not infect Hosta in greenhouse inoculation trials.

    9. Theorized Rust Life Cycle

    10. Rust Spread Can it be transmitted in seed? Dont know, but unlikely Can it be spread by tools, clothing, hands? Yes, mostly on hands Is it spread by the wind? Yes, primary means of spread from plant to plant How far can it be spread by wind? Dont know, but in theory it can spread miles

    11. Systemic Survival and Spread Can it survive systemically within daylily? Doubtful, infection of daylily is urediniospores and binucleate hyphae; uninucleate hyphae is perennial How does rust spread throughout plant? By urediniospores mostly, but can spread as binucleate hyphae within the leaf Does it spread from leaf to leaf or systemically through the crown? Spread is leaf to leaf, no evidence of systemic spread

    12. Rust Survival Can it survive cold temperatures? Yes, if plant tissue is present Can it survive in the soil? No, must have living tissue to survive How long are urediniospores viable? Dont know, but appears to be short period Can it survive the winter? Is there hope? Survival in my garden

    13. Rust Infection Can rust lie dormant for a period of time? Possibly, spore production appears to be reduced during periods of high (hot) temperatures Environmental conditions required for rust spore production, germination, spread? Dont know all requirements, do know about spore germination

    15. Fungicide Definitions Contact or Protectant - applied preventively; acts on spore germination to early infection (penetration of host tissues), no disease symptoms develop. Systemic - moves into the plant, mostly redistributes towards plant apex or leaf margins (acropetal movement) Curative - acts on post-infection, pre-symptomatic phase Eradicant - acts to stop host colonization, after symptoms develop

    16. Fungicide Definitions What does translaminar systemic or mesosystemic mean? Unique to strobilurins (ex: Compass); fungicide redistributes in waxy cuticle of leaf, and will diffuse from the sprayed surface, so that after a few days, enough accumulates on the other to provide fungicidal protection of the unsprayed side.

    22. Fungicide Recommendations Daconil, Fore, and Heritage work the best at stopping rust infection Apply weekly because new infections are constant and plants are actively growing Banner Maxx, Systhane (sterol inhibitors) do not stop infection, but they may have a role in stopping post-infection spread and pustule development Still needs to be tested in fungicide trials Always use labeled rates; using less may lead to resistance, too much to phytotoxicity

    23. Rust Control during the Winter Should infected foliage be removed? Yes, infected foliage (all foliage) should be removed, especially evergreen or semi-evergreen varieties and dormants if they dont go dormant Should fungicide applications continue in winter? If green tissue is present and it is a mild winter then spraying will be necessary.

    24. Current Rust Research and Collaborations Fungicide evaluations Leaf wetness and humidity requirements for spore germination and infection Cultivar susceptibility Rust survival Spore longevity and spread Genetic variability within rust populations Enlistment of AHS members in rust evaluations and observations within their gardens

    25. Susceptibility of 25 Cultivars Very Susceptible (12) Pardon Me, Ming Toy, Lemon Yellow, Quannah, Pandoras Box, Little Gypsy Vagabond, Karie Ann, Colonel Scarborough, Double Buttercup, Irish Ice, Russian Rhapsody, Imperial Guard Moderately Susceptible (9) Stella DOro, Happy Returns, Butterflake, Prelude to Love, Gertrude Condon, Joan Senior, Wilsons Yellow, Star Struck, Crystal Tide Low Susceptibility (4) Mac the Knife, Yangtze, Butterscotch Ruffles, Holy Spirit