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Leaf Rust on Daylily. Identified in Georgia in August 2000 on cv. Pardon Me brokered from Costa Rica. Daylily rust symptoms. Cultivars vary in susceptibilitySymptoms vary with cultivar. 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, VASpread mostly through the sale or trading of infected plantsInfected plants should be removed or the foliage cut off at the soil31151
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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?
Don’t 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?
Don’t 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?
Don’t 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?
Don’t 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 don’t 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, Pandora’s Box, Little Gypsy Vagabond, Karie Ann, Colonel Scarborough, Double Buttercup, Irish Ice, Russian Rhapsody, Imperial Guard
Moderately Susceptible (9)
Stella D’Oro, Happy Returns, Butterflake, Prelude to Love, Gertrude Condon, Joan Senior, Wilson’s Yellow, Star Struck, Crystal Tide
Low Susceptibility (4)
Mac the Knife, Yangtze,
Butterscotch Ruffles,
Holy Spirit