diseases of woody ornamentals - hurricane electric€“plant/produce resistant ... •baking soda...

6/12/2009

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Diseases of Woody Ornamentals

• Causes: Pythium spp., Phytophthora spp.,

Rhizoctonia solani, Fusarium spp.,

Cylindrocarpon spp.

• Hosts: Anything and everything

• Environmental triggers

– High soil moisture

– Cool soil temperatures

Diseases of Woody OrnamentalsRoot/Crown Rots

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• Control:

– Moderate soil moisture

• Grow woody ornamentals in well-drained sites

• Use a soil with adequate drainage

• Improve drainage in poorly drained soils

– Add organic matter to improve drainage

– Use raised beds

• DO NOT overwater

• DO NOT overmulch


• Control:

– DO NOT move contaminated soil or plants to non-

infested areas

– Decontaminate infested tools, pots, work areas

– Pretest soils/mulches/composts for the presence of

root rot fungi

– Use a soil-less potting mix for containerized plants


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• Control:

– Decontaminate recycled water

• Filtration

• Irradiation

• Chemical treatment


• Control:

– Use fungicides to prevent infections

• Etridiazole, metalaxyl, mefenoxam, fosetyl-Al,

PCNB, thiophanate-methyl, fludioxonil

• Use granular formulations if possible

• Use during periods of wet weather

– Use biopesticides to prevent infections

• Trichoderma, Gliocladium

• Use in pot production


• Causes: Ophiostoma ulmi = Ceratocystis ulmi

Ophiostoma novo-ulmi

(Pesotum ulmi = Graphium ulmi)

Diseases of Woody OrnamentalsDutch Elm Disease

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• Hosts:

– Highly susceptible elms

• American, Belgian, English, red, rock, September,

European white, winged

– Elms of intermediate susceptibility

• Cedar, European field (smooth-leaf), wych (Scots)

• Environmental trigger: Cool, wet conditions


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• Transmission

– Elm bark beetles

• Scolytus multistriatus (European)

• Hylurgopinus rufipes (Native)

– Root grafts

• Major method of movement

in clumps of elms

• Ophiostoma ulmi can reach

the roots during the first

season of infection


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• Control:

– Remove diseased elms

– Disrupt root grafts

• Mechanically (vibratory plow or trenching machine)

• Chemically (soil fumigant)

• Physical barriers

– Be careful using elm wood

• Remove bark

• Cover wood


• Control:

– Prune diseased branches

– Use fungicides injections

• Propiconazole, thiabendazole

• Prophylactic or therapeutic

• Every 12-24 months


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• Control:

– Plant resistant elms

• Crosses between American and other elms

• True American elms

– American Liberty

– Independence

– Princeton

– Valley Forge

– New Harmony


• Control:

– Treatments of dubious use

• Tracing

• Verticillium dahliae


• Cause: Ceratocystis fagacearum

(Chalara sp.)

• Hosts

– About 20 species of oak

– Black/red oak group: northern red, northern pin, black

– White oak group: white, bur, swamp white

– Chinese chestnut

• Environmental trigger : Cool, wet conditions

Diseases of Woody OrnamentalsOak Wilt

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• Transmission

– Oak bark beetles

• Pseudopityophthorus ninutissimus

• Pseudopityophthorus pruinosus

– Sap beetles

• Carpophilus spp.

• Colopterus spp.

• Cryptarcha spp.

• Epuraea spp.

• Clischrochilus spp.


• Transmission

– Root grafts

• Major method of movement

in clumps of oaks

• Can form between trees

in the same subgenus

– Black/red oak group

– White oak group

• Movement of up to 20-25 ft/year


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• Control

– Do not prune or wound oaks from bud break to 2-3

weeks past full leaf development

– Disrupt root grafts

• Mechanically (vibratory plow or trenching machine)

• Chemically (soil fumigant)

• Physical barriers

– Remove diseased (and healthy) trees


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• Control

– Be careful using oak wood

• Remove bark

• Cover wood

– Use fungicide injections

• Propiconazole

• Prophylactic or therapeutic

• Every 12-24 months


• Causes: Verticillium dahliae

Verticillium albo-atrum

• Hosts:

– Many woody ornamentals

– Many herbaceous plants

– Maple, ash, redbud, smokebush

• Environmental trigger: Cool, wet weather

Diseases of Woody OrnamentalsVerticillium Wilt

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• Control

– Avoid Verticillium-infested areas

– Pretest soils/mulches/composts for the presence of

Verticillium

– Fumigate heavily infested soils

– Keep broad-leaf weeds under control

– Avoid municipal mulches


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0

10

20

30

40

50

60

70

80

90

100

0 2 4 8 16 32 62 122 182 242 302 362

Days in Mulch Pile

Percentage of Infested Chips 'Legacy' sugar maple

wood chips

% Recovery of Verticillium from Wood Chips

• Wood Chips as an

Inoculum Source

– Amur maple

• 30.0%/25.0% (Trted)

• 0.0%/0.0% (Non-Trted)

– Green Ash

• 23.7%/10.5% (Trted)

• 0.0%/0.0% (Non-Trted)

– Redbud

• 10.7%/13.3% (Trted)

• 0.0%/0.0% (Non-Trted)

• Control

– Use resistant plants

• CONIFERS: Pines, spruces, firs, junipers

• DECIDUOUS TREES/SHRUBS: Beech, birch, ginkgo,

hackberry, hawthorn, hickory, honey locust, mountain ash,

white oak, bur oak, poplar, serviceberry, sycamore, willow


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• Control

– Prevent plant stress

– Prune diseased (wilted) areas

– Make infected trees comfortable until they die

– Remove diseased plants

– Destroy infected materials

– Composting?


• Cause: Micronutrient (Fe or Mn) deficiency

• Problem trees

– Oaks

– Red Maples

– Other woody plants can also be affected

• Environmental trigger: High soil pH


Chlorosis

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• Control:

– Monitor soil pH and soil nutrients

– Decrease pH using sulfur or aluminum sulfate

– Add chelated Fe and/or Mn as needed

– Make sure trees are adequately watered

– Minimize damage to trees’ root systems


Chlorosis

• Cause: Erwinia amylovora

• Hosts

– Many rosaceous plants

– Apple, crabapple, pear, mountain ash, cotoneaster

• Environmental trigger: Hail

Diseases of Woody OrnamentalsFire Blight

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• Control

– Plant resistant varieties where available (Prairiefire)


– Do not over-fertilize with nitrogen

– Use bactericides to prevent infections (?)

• Copper-containing fungicides, antibiotics

• During flowering

• Applications every 7-14 days (3-4 days)

Diseases of Woody OrnamentalsFire Blight

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• Cause: Cryptodiaporthe corni

• Hosts

– Alternate-leaved dogwoods

– Pagoda dogwood

• Environmental trigger: Water, heat stress

Diseases of Woody OrnamentalsGolden Canker

• Control


– Reduce plant stress

• Consider tree placement

• Water adequately

• Fertilizer appropriately

– Do not use fungicides for control

Diseases of Woody OrnamentalsGolden Canker

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• Cause: Apiosporina morbosa

• Hosts

– Prunus species

– Plums

– Cherries

• Environmental trigger: Long periods of wetness

Diseases of Woody OrnamentalsBlack Knot

• Control

– Don’t plant infected Prunus stock

– Buy black knot-resistant varieties if available

– Remove volunteer plums/cherries


– Don’t use fungicides

Diseases of Woody OrnamentalsBlack Knot

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• Causes: Gloeosporium spp.

Collectotrichum spp.

Other fungi

• Hosts:

– Anything and everything

– Ash, maple, oak

• Trigger: Cool, moist conditions in May/June

Diseases of Woody OrnamentalsAnthracnose

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• Control

– Don’t panic

– Remove diseased leaves


• Copper-containing fungicides, chlorothalonil, mancozeb,

thiophanate methyl

• 3 appplications at bud break, 1/2 expansion of leaves, full

leaf expansion

Diseases of Woody OrnamentalsAnthracnose

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• Causes: Tubakia spp. (Actinopelte spp.)

• Hosts:

– Oaks

• Environmental trigger: Hot, wet late summer

weather

Diseases of Woody OrnamentalsTubakia (Actinopelte) Leaf Spot

• Control

– Don’t panic

– Remove diseased leaves

• Burn

• Bury

• Compost

– Do not use fungicides

Diseases of Woody OrnamentalsTubakia (Actinopelte) Leaf Spot

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• Cause: Venturia inaequalis

• Hosts

– Apple

– Crabapple

– Pear

– Mountain ash

• Environmental trigger: Cool, wet spring weather

Diseases of Woody Ornamentals Scab

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• Control

– Plant/produce resistant varieties (Prairiefire)

– Remove and destroy infested leaf debris

– Thin trees to promote air flow


• Chlorothalonil, mancozeb, myclobutanil, propiconazole,

thiophanate-methyl

• From bud break through the end of favorable weather

• Applications every 7-14 days

Diseases of Woody OrnamentalsScab

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• Pathogen: Marssonina rosae

• Host: Rose

• Environmental trigger: Long periods of leaf

wetness

Diseases of Woody OrnamentalsBlack Spot

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• Control:

– Plant/produce resistant rose varieties

– Do not overcrowd rose plantings

– Do not overhead water

– Do not overwater

– Prune rose shrubs to remove diseased canes and open

the plant canopy

– Remove and destroy infested leaf debris


• Control:


• Chlorothalonil, copper-containing fungicides, mancozeb,

maneb, myclobutanil, propiconazole, thiophanate-methyl

• Baking soda (1.5 Tsp/gal) and horticultural oil (3 Tsp/gal)

• Neem oil

• 7-14 day application interval


diseases of woody ornamentals - hurricane electric€“plant/produce resistant ... •baking soda...

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