Daylily rust research update

(presented at Nursery Growers' Short Course, Feb 12 2003, Royal Botanical Gardens, Burlington, Ontario)

Dr. Tom Hsiang, Dept. Environmental Biology, Univ Guelph

Leaf lesions

Leaf rust pustule

Rust pustule (large)

Rust pustule (larger)

Rust spores

Daylily rust

native to east Asia

first detected in North America in fall 2000

in 2001, found in collector/breeding gardens in Ontario and Quebec

our research started in January 2002

Research Personnel

Tom Hsiang (Univ. Guelph)

Michelle MacDonald

Sarah Bowerman

Moh Afunian

Yong Zhao

Sandra Cook

Jen Llewellyn (OMAF)

Wayne Brown (OMAF)

Funding

Syngenta (3k)

Landscape Ontario (5k)

American Hemerocallis Society (10k)

Research objectives

rust production & inoculation methods

cultivar resistance

fungicide efficacy

rust incubation period

rust spore survival

rust winter survival

Rust production

Cultivar resistance

leaf pieces inoculated in petri plates

Cultivar resistance (spots/leaf)

Catherine Woodbery	11.4 spots
Cherry Cheeks	8.7 spots
Pardon Me	8.5 spots
Fulva	6.9 spots
Cleopatra	4.6 spots
Rosy Returns	3.6 spots
Summer Wine	3.5 spots
Happy Returns	2.6 spots
Pandora’s Box	1.7 spots
Stella D’oro	0.5 spots

~40 leaves per cultivar, LSD_0.05 = 5.3

Greenhouse & outdoor test

started July 17, 2002 at Vineland

fungicide treated 2 times (wk1 & 3)

inoculated with rust 3 times (wk1, 3 & 5)

moved on Aug 28 to Guelph outside the Bovey greenhouses

final rating on Oct 10, 2002

Greenhouse treatments

cv. "Pardon Me"

8 treatments, 5 plants for each, 50 ml/plant

Results

Trade name	Chemical name	product/L water	product /100 gal
1. Banner 130EC	14.3% propiconazole	0.67 ml	8 fl oz
2. Daconil 2787F	40% chlorothalonil	2.5 mL	30 fl oz
3. Daconil Ultrex	82.5% chlorothalonil	1.7 g	1.4 lb
4. Fore 80WP	80% mancozeb	0.83 g	1.5 lb
5. Heritage 50WG	50% azoxystrobin	0.3 g	2 - 4 oz
6. Nova 40W	40% myclobutanil	0.3 g	4 oz
7. dishwashing liquid	Ultra Dawn	1%	1%
8. untreated control	water	only water	only water

Fungicide application

Rust inoculation (1 day after)

Bagged for 24 hours

Greenhouse test results

no rust seen in Vineland (too hot)

rust appeared at Guelph in early October (cooler & wetter weather)

rust probably infected plants after inoculation in July & August, but symptoms didn’t appear for 2-3 months (October)

Greenhouse test results

Lab tests with leaves

3 plates with 4 leaf pieces per treatment

each leaf dipped in fungicide solutions for 5-10 sec

Figure: fungicide 1 day before inoculation

Figure: fungicide 1 day after inoculation

Figure: fungicide 3 days after inoculation

Figure: fungicide 7 days after inoculation

Other research

incubation period (in progress)

spore survival (in progress)

rust winter survival (in progress)