Daylily Rust Puccinia hemerocallidis in the United States

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
Uredinial/telial host Daylily (Hemerocallidaceae)
and Hosta (Liliaceae)????Aecial host
Patrinia spp. (Valerianaceae)
Heteroecious Rust

• Patrinia scabiosifolia
• (Golden Valerian)
• P. gibbosa
• P. triloba
• P. villosa
• P. rupestris

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
(uninucleate hyphae)
Aeciospores
Spermatia
Repeating stage
Urediniospores
Teliospores
Basidiospores
(binucleate hyphae)
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

14
(No Transcript)
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.

Heritage (azoxystrobin) redistributes within
the leaf in the same way, but it is also systemic
and can move within the leaf.
17
(No Transcript)
18
(No Transcript)
19
Fungicides Used in Preliminary UGA Daylily Rust
Trials
Trade Name
Active Ingredient
Suggested rate
Propiconazole Flutalonil Chlorothalonil Mancozeb A
zoxystrobin Triadimefon Myclobutanil
8 fl. oz/100 gal 3 - 6 oz/100 gal 1.4 lb/100
gal 1.5 lb/100 gal 2 - 4 oz/100 gal 4 oz/100
gal 4 oz/100 gal
Banner Maxx Contrast Daconil Ultrex Fore Heritage
Bayleton Systhane
20
(No Transcript)
21
Note Heritage in this trial is without added
wetting agent
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

Donated plants screened within a greenhouse