Id-88: woody plant disease control guide for kentucky

C O O P E R A T I V E E X T E N S I O N S E R V I C E U N I V E R S I T Y O F K E N T U C K Y • C O L L E G E O F A G R I C U L T U R E
WOODY PLANT DISEASE CONTROL
GUIDE FOR KENTUCKY
by John Hartman, Mary Witt, Don Hershman, and Robert McNiel Cultural Practices to Prevent Disease
Good care of trees and shrubs prevents many nursery and landscape problems. Because trees and shrubs live for manyyears, their susceptibility to disease is influenced not only bycurrent climatic and environmental conditions but also byconditions and care during previous years. Adverse growingconditions, maltreatment, and lack of care favor manydiseases. Many problems in nurseries and landscapeplantings can be avoided by selecting proper plant materials,creating good planting sites, avoiding unnecessary wound-ing, providing routine care (including fertilization and timelywatering and pruning), and using preventive disease andinsect control measures as needed.
Woody plants may be stressed or grow poorly for a variety of reasons, some natural and some caused by people.
In any case, these stressed plants are often susceptible todiseases that would otherwise not be a problem. Stresses areoften alleviated or moderated by proper plant care. SeveralUK Cooperative Extension publications, available from yourcounty Extension office, cover this topic.
Nursery and Landscape Hygiene
Careless hygiene can ruin one’s investment in disease- free plants and clean soil. Soil-borne pathogenic fungi,bacteria, and nematodes are carried into the nursery or • Wash boots and hand tools along with mechanical
landscape and spread by footwear, implements, tools and machines, moving surface water, blowing soil, and plants.
• When roguing diseased plants or pruning diseased parts of
Nurseries are especially vulnerable to outbreaks of plants, destroy or bury the discards.
contagious diseases, so take extra precautions.
• Divert surface water into ditches or culverts to prevent its
• Before planting, insist on clean stock. Do not order or accept
movement from one nursery block to another.
stock likely to be infected with nematodes, crown gallbacteria, or highly destructive soil-borne fungi such as • Remember that irrigation water can carry pests and
Phytophthora, Thielaviopsis, or Verticillium.
pathogens. Select a clean source and keep it from becomingcontaminated.
• Where practical, stabilize all open soil near the nursery and
maintain windbreaks. Cover dirt roads with gravel or oil.
• Allow no direct traffic from outdoor areas to indoor
propagation areas. Clean footwear with a germicidal agent
• Require equipment moving between nursery blocks to
such as LF-10 or Amphyl at entrances.
pass through a central area where soil is washed off.
Equipment can be parked on a bed of coarse rock, and soil • When collecting cuttings in the field, inspect stock plants
particles will be carried down through the stones. A steel carefully and avoid any plants showing disease symptoms or grating over a pit is an even better arrangement for a • Disinfect tools regularly when pruning to control disease or
AG R I CU LTU R E • HO M E E CONO M I CS • 4 -H • D EV E LO P M E N T when collecting cuttings. An easy, effective way to do so is to at one end to the screw and at the other end to a hydraulic swab the cutting blades with denatured alcohol (mix 7 parts sprayer capable of building high pressures. The fungicide is alcohol with 3 parts water). Chlorine bleach diluted 1:5 with then pumped into the tree at high pressure. Only experienced water is also effective. A vial or other pocket-sized container professional arborists should use such apparatus.
will hold a cotton swab saturated with the disinfecting The Elm Research Institute can provide information solution. Rinse tools in water at the end of the day to remove about controlling Dutch elm disease using a low pressure corrosive bleach or rubber-softening alcohol.
system for injecting fungicide into elm trees. Thearrangement of a series of T-shaped nozzles connected to one Using Fungicides and Bactericides
another with tubing is similar to the one used for the high Most of the diseases listed in this publication do not require annual or regular chemical treatments for control.
Spraying Equipment. Small trees and shrubs can be
Exceptions include rose diseases and diseases of susceptible sprayed with hand-pumped, bucket, hose-end, backpack, or flowering crabapples. Consider routine chemical application small power sprayers. Large trees can only be properly for disease control only when the disease is a known threat sprayed with large spraying machines. Such machines are (has occurred in previous seasons, is present in nearby expensive and are mainly owned by commercial arborists and landscapes, is expected in your operation, or is so devastating park and shade tree departments doing considerable tree that routine prevention is essential) and when the plant being • Hydraulic Sprayers apply sprays to tall trees in a so-called
Most fungicides and bactericides are protectants and solid stream; that is, the material leaves the nozzle much as must be on the plant before infection begins. Some fungicides water issues from a fire hose. The stream, forced out under are systemic types, however, and can eradicate new great pressure, soon reaches a height, however, at which it infections. Rainy, foggy weather favors most infections; breaks into a mist and drifts onto leaves and stems.
therefore, apply protectant sprays before such weather Smaller trees are sprayed with a hydraulic sprayer that conditions occur. Extra sprays may be needed during wet breaks the liquid into a fine mist as soon as it leaves the years, and few or no sprays may be needed during warm, dry, nozzle, giving rapid and complete coverage. Most hand-held spray guns have nozzles that can be adjusted to accomplishboth types of spraying.
Chemical Application
• Mist Blowers (or air sprayers) use blasts of air to propel
Methods and Equipment
droplets of pesticide, in contrast to hydraulic sprayers whichuse water as the vehicle for the pesticide. With such Good injecting or spraying equipment and techniques machines, it is possible to cover more trees in a shorter time are essential for successful control of diseases.
at far less cost. Using highly concentrated materials not only Injections and Implants. Techniques and materials
speeds up refilling time, but sharply reduces runoff or drip have been developed for controlling specific diseases in waste, which is a major component of lost pesticide for certain trees by injecting fungicides into the sapstream at the trunk’s base or on the flare roots. These systems are useful Mist blowers come in several sizes and types. Some are where sprays cannot be used. Much less chemical is needed, more suitable for use on large shade trees, and others are and it is all delivered into the tree not into the surrounding better adapted for nursery plantings. Small motor-powered environment. Problems of uneven distribution of chemicals backpack mist blowers are now available for low-growing in the tree crown do sometimes occur, however, and each plant materials. Several companies manufacture spraying injection creates a wound that is a potential colonization site machines. Your local pesticide dealer has information on for decay fungi. In this regard, the smaller the injection, the prices and specifications of spray equipment.
better. If a problem requires annual injection, the injurycaused by injection is probably more damaging than the The object of spraying is to cover every leaf, twig, and branch that might become infected by a pathogen. Thorough Injector units using the Mauget system and similarly coverage is especially essential when using protectant constructed units for injecting fungicides into trees (e.g., fungicides. For protection against infectious diseases, both Alamo) consist of a small plastic cylinder containing leaf surfaces usually need to be covered. Because systemic fungicide attached to a short plastic tube inserted into a pre- fungicides are transported throughout the plant, complete drilled hole in the trunk. Installing injector units requires coverage for them is less important. Because of concerns over knowledge and practice. Accordingly, these are used by drift of pesticides to neighboring property, sprayers capable arborists, nursery operators, and horticulturists who have had of covering large trees should be used with caution.
An apparatus is also available for injecting liquid Wetting, Spreading, and Sticking Agents
fungicides into the tree by gravity or under high pressure.
Wetting, spreading, and sticking agents (surfactants), Small holes are first bored into the tree trunk to the depth of often combined in commercial preparations as spreader- the outer layers of sapwood. A special injector tap or screw is stickers, need to be used in some spray mixtures. They are then inserted into the hole. A high-pressure hose is connected particularly necessary when pesticides are applied to hard-to- wet broadleaf evergreens or conifers. Follow directions on Karbam Black; General protectant fungicide. May leave black residue on flowers and foliage.
The fungicide label usually indicates any restrictions in folpet — Phaltan, Folpet; Rose and garden fungicide.
selection of compatible surfactants. The following are fosetyl-Al — Aliette; Foliar and soil drench fungicide
surfactants commercially available for tank mixing: Biofilm used for systemic control of Pythium and Phytophthora Spreader-Sticker, Chevron Spray Sticker, Chevron Spreader, Citowett (spreader-sticker), Multifilm L (spreader), Nu-film funginex — Triforine; Rose disease control fungicide.
P (spreader-sticker), Nu-Film 17 (spreader-sticker), Ortho X- Gallex — For therapeutic treatment of crown gall.
77 (spreader), Pinolene (sticker), Spray Stay (spreader- Galltrol-A, Norbac-84 (Agrobacterium radiobacter
sticker), Sure Spred (spreader), Surfactant 11 (spreader), and strain 84) — A preventive biocontrol of crown gall.
iprodione — Chipco 26019; Broad spectrum, locally
Materials Used to Control Diseases
mancozeb — F-45, Fore, Mancozeb, Penncozeb,
Protect T/O; General protectant fungicide for foliar diseases.
of Woody Plants
maneb — Dithane M-22, Maneb, Manex, Blitex, Chem
(Follow label instructions.)
Neb; General protectant fungicide for foliar diseases.
Fungicides are listed in this section, alphabetically by MBC phosphate — Lignasan BLP, Elmosan, Elm-
common chemical name followed by trade name and Noculate, Correx, Elmpro, Fungisol; Soluble systemic fungicide or bactericide uses and remarks.
fungicide injected for Dutch elm disease control.
benomyl — Benomyl WP; Fungicide with some
metalaxyl — Subdue 2E Subdue II; Systemic soil
systemic properties; effective against many diseases.
drench fungicide used to control Pythium and Phytophthora Tolerant strains of Botrytis, rose powdery mildew, and the apple scab fungus now occur. Do not use benomyl alone.
pentachloronitrobenzene — Terraclor, PCNB; Fungi-
Rather alternate or tank mix with other fungicides.
cide used principally to control Rhizoctonia using soil drench Ineffective against Pythium, Phytophthora, and similar fungi.
applications or incorporated into soil in dry form. May Benlate, a product containing benomyl, is not labeled for suppress root development in cuttings.
landscape use, though other benomyl forms are.
piperalin — Pipron; Powdery mildew fungicide for
bordeaux mixture — Bordeaux mixture, Bordo,
Copper Bordo; Equal parts by wt. copper sulfate (bluestone) propamocarb — Banol; For control of Phytophthora
+ hydrated lime in water; most effective if freshly mixed but dried Bordeaux preparations are available. Some species propiconazole — Banner, BannerMaxx, Alamo, Immunex;
of Ilex may be injured by copper. Proportions of chemical Locally systemic fungicide effective for anthracnose, scab, in the mixture can vary and are often expressed as pounds powdery mildew, and rust diseases. Alamo is injected for Dutch of copper sulfate, pounds of hydrated lime, and gallons of streptomycin — Ag-Strep, Agrimycin, Phytomycin,
captan — Captan Fungicide, Captan, Orthocide, Captan
Antibiotic spray powder, Streptomycin spray, Streptomycin Dust; General protectant fungicide used for foliage diseases.
WP, Streptomycin C 17; Antibiotic effective against bacteria Sometimes used for control of damping-off fungi.
but not fungi. Ineffective at low temperature. May cause chlorothalonil — Daconil 2787, Bravo 720; Broad-
phytotoxicity at high rates during hot weather. Effectiveness spectrum fungicide for control of foliage diseases including is favored by slow drying conditions. Not recommended for copper (fixed) — [see also Bordeaux mixture] Basic
sulfur — Sulfur dust, wettable, Thiolux, Liquid lime-
Copper Sulfate, Tribasic copper sulfate, Basi-Cop, Microcop, sulfur; Elemental sulfur is a fungicide for powdery mildew; Copper 53 Fungicide, T-B-C-S 53, copper oxychloride lime-sulfur can serve as both fungicide and insecticide and is sulfate; General protectant fungicide. May be phytotoxic to new spring growth, especially Ilex spp.
thiabendazole — Arbotect 20-S; Systemic fungicide
copper hydroxide — Kocide 101, 606, DF, Champion;
injected for Dutch elm disease and for sycamore anthracnose General protectant fungicide. May be phytotoxic.
copper sulfate pentahydrate — Phyton 27; Fungicide
thiophanate-methyl (dimethyl 4, 4-o-phenylenebis-
for Dutch elm disease control via injection.
[3,thioallophanate]) — Cleary’s 3336, Fungo-Flo, Fungo dodemorph acetate — Milban; For commercial
DF, Domain FL, 3336 WP, Topsin M; Systemic fungicide greenhouse use only; controls powdery mildew.
having properties similar to benomyl.
etridiazole (ethazole) — Terrazole, Truban; Soil drench
triadimefon — Bayleton, Strike; Systemic fungicide for
fungicide useful against Pythium, Phytophthora damping- control of powdery mildew, rust diseases, some leaf spots, fenarimol — Rubigan AS; Locally systemic fungicide
vinclozolin — Ornalin, Curalan DF; For control of
for control of powdery mildew and apple scab.
ferbam — Carbamate T&O, Carbamate WDG, Ferbam,
ziram — Ziram; General protectant fungicide.
Fungicide Mixtures
chlorinated hydrocarbons (some formulations are
mixed with chloropicrin) — Telone C-17; Fumigant.
clorothalonil + fenarimol — Two Some; Combination
Controls nematodes, soil insects, some soilborne diseases, protectant and locally systemic fungicide controlling a wide and many weeds. Apply in spring or fall when soil temperature is above 40°F. Plant when fumigant odor is gone ethzole + thiophanate methyl — Banrot; Broad-
spectrum fungicide for control of root rot diseases of chloropicrin (some formulations are mixed with
chlorinated hydrocarbons or methyl bromide) — Chlor-O- thiophanate-methyl + mancozeb — Zyban, Duosan;
Pic, Picfume, Larvabrome, Nemex, Telone II; General soil Broad spectrum systemic and protectant fungicide combination.
fumigant. Corrosive to metal; water or plastic seal necessary.
Apply only when soil temperature is 60°F or higher. Aerate Soil Fumigation
soil by cultivation until odor is gone before planting — 2 to 4 General-purpose soil fumigants are designed to eradicate essentially all soil organisms including fungi, fenamifos — Nemacur; Nematicide with systemic action.
bacteria, nematodes, soil insects, plants, and seeds.
Protects ornamentals against the major nematode genera.
Commonly used materials are methyl bromide, chloropicrin, methyl bromide (some formulations are mixed with
sodium methyldithiocarbamate, and mixtures containing two chloropicrin) — Brom-0-Gas, Dowfume MC-2, Dowfume or more active ingredients. Consider using a general-purpose MC-33, Brozone, Nemaster; General soil fumigant; odorless, fumigant for rehabilitation of high value soil infested with therefore usually mixed with small amounts of chloropicrin damaging populations of nematodes or root disease fungi.
to impart odor. Applied under plastic tarp or by injectionfollowed by tarp application. Soil must be 50°F or above.
Leaves bromide residue in soil. Be aware that this chemical is 1. Soil fumigation is most effective when soil is warm
being gradually phased out over concerns that it facilitates and moderately moist, like summer or early autumn.
2. Cultivate soil at least 12 in. deep, providing a uniform
oxamyl — Vydate; Systemic insecticide-nematicide;
loose texture. Remove roots and other non-rotted plant debris.
has broad-spectrum nematicidal activity when applied to soil; 3. Work the soil to seedbed condition to achieve effective
is unique in functioning as a nematicide when applied to sealing of the surface by a roller or cultipacker after injection foliage of certain plants. Fruit nursery plant applications.
sodium methyldithiocarbamate — Vapam, Busan 1020;
4. Inject the chemical 6 to 8 in. deep or half the depth of
General soil fumigant; applied by injection or as drench. Also used to prevent root-graft transmission of Dutch elm disease.
5. Carefully adhere to minimum waiting periods before
planting as indicated on product labels.
Woody Plant Disease Control
6. It may be necessary to aerate the soil by cultivation.
7. Be aware of potential side effects, such as toxic
ALL SPECIES
bromide residues and increases in soluble salts and nitrogen Anthracnose and leaf spots
Control: Sprays are usually not needed. Provide the 8. Follow all label directions.
growing site with good air movement and sunlightpenetration by pruning and spacing. Rake up and destroy Nematode Control
fallen infected leaves in autumn. If disease has been severe Soil-borne nematodes can be controlled using nemati- the previous year and cool, wet conditions are expected in cidal fumigants like chlorinated hydrocarbon compounds spring, spray with bordeaux mixture, chlorothalonil, applied before planting. Follow guidelines listed previously chlorothalonil + fenarimol, copper (fixed), mancozeb, mancozeb + thiophanate-methyl, maneb, propiconazole, or Fenamifos and oxamyl are useful for postplanting thiophanate-methyl. Repeat 2 to 3 times at 10- to 14-day nematode control treatments on a wide variety of woody intervals, beginning at bud break. NOTE: Read the fungicide plants. These chemicals also control some insect pests. These label to be sure that the specific plant and disease are listed.
nematicides can also be used for preplant treatments. Consult The plant and disease list for each fungicide is different.
Dieback, decline
Control: Keep trees well-watered, especially from May Uses for Soil Fumigants &
to July. Prune out dead and dying branches. Prevent decline Nematicides
by routine care and tree placement to avoid salt exposure andsoil compaction. Sever girdling roots as needed. Control (Follow label instructions.)
defoliating insects. Aerate compacted soil in root zone.
Fumigants, fumigant mixtures, and nematicides are listed in this section, alphabetically by common chemical Powdery mildew
name followed by trade name and fumigant or nematicide Control: Provide growing site with good air movement and sunlight penetration by pruning and spacing. Apply benomyl, dodemorph, fenarimol, propiconazole, thiophanate- 4 times at 10- to 14-day intervals beginning when buds open.
methyl, triadimefon, wettable sulfur, ziram, or mancozeb + Weather conditions and severity of disease determine thiophanate-methyl weekly beginning when disease symptoms number of applications needed. The following species and first appear. Check fungicide labels for specific plants cleared.
varieties are reported to be resistant to leaf blotch: Aesculusarguta, A. glabra var. monticola, A. glabra var. sargentii, A.
Root and cutting rot of propagation and overwinter-
parviflora, and A. parviflora var. serotina.
ing stock
Control: Provide good sanitation, clean plant materials AMELANCHIER (serviceberry)
and growing media, and good soil drainage. Fungicide Powdery mildew
drenches, where labelled for specific crops, may be used. For Control: See suggestions under ALL SPECIES.
water molds, use products containing metalaxyl, fosetyl-Al,or ethazole. For Rhizoctonia or other fungi, use benomyl, Rust
PCNB, thiophanate-methyl, or iprodione.
Control: See suggestions under MALUS.
Storage mold of nursery stock
BETULA (birch)
Control: Maintain cold storage near freezing. Apply captan Leaf rust, leaf spots
or benomyl in the field or just before nursery stock is packed.
Control: Rake up and destroy fallen leaves.
Verticillium wilt
BUXUS (boxwood)
Control: Practice strict nursery hygiene. It is difficult to disinfest contaminated soil even using soil fumigation.
Macrophoma and other leaf spots
Rogue out infected nursery plants. In the landscape, prune out Control: Use sanitation measures as for canker. Fertilize infected branches, or remove badly infected plants. Fertilize and protect from winter injury to maintain vigor. Sprays not and water landscape plants. Replace with Verticillium wilt resistant plants, e.g., Betula spp., Buxus spp., Cercidiphyllum Nematodes
japonicum, Carpinus spp., Cornus spp., Crataegus spp., Control: Apply soil insecticide/nematicide fenamifos.
Ginkgo biloba, Fagus spp., Gleditsia triacanthos, Ilex spp.,Juglans spp., Liquidambar stryaciflua, Malus spp., Morus Pseudonectria canker
spp., Platanus spp., Pyracantha spp., Quercus spp., Pyrus Control: Plant in well-drained soil and protect from spp., Salix spp., Sorbus aucuparia, Tilia spp., and needled drying winter winds. Prune infected branches back to healthy wood. In spring, if possible, remove and destroy old leaveslodged in branches (a strong stream of water helps).
ACER (maple)
Anthracnose
CARYA (hickory)
Control: See suggestions under ALL SPECIES.
Fungal leaf spots
Control: Rake up and destroy fallen leaves. Sprays are Fungal cankers
usually not necessary. If disease has been severe, see Control: Fertilize and water as needed to provide good growing conditions for maintaining plant health. Avoidinjuries. Remove and destroy cankered branches or excise CASTANEA (chestnut)
Blight, Endothia (Cryphonectria) parasitica
Phyllosticta and other leaf spots
Control: Prune away and destroy cankered limbs.
Control: See suggestions under ALL SPECIES.
Cankers in landscape trees can be treated with a soil-waterpaste held in place with plastic. Treated cankers will begin Taphrina leaf blister
remission. American chestnut is extremely susceptible; Control: Sprays usually not needed. A single dormant application of lime sulfur will control this disease.
CATALPA
Verticillium wilt
Fungal leaf spots
Control: See suggestions under ALL SPECIES. Norway Control: Rake up and destroy fallen leaves. Sprays are maples tolerant or resistant to Verticillium wilt include: usually not necessary. If disease has been severe, see ‘Columnare Compacta’, ‘Jade Glen’, and ‘Parkway’.
suggestions under ALL SPECIES. Spray as leaves are AESCULUS (horsechestnut, buckeye)
unfolding, when leaves reach full size, and 2 weeks later.
Abiotic scorch
Verticillium wilt
Control: Provide adequate water.
Control: See suggestions under ALL SPECIES.
Guignardia leaf blotch, leaf spots
CELTIS (hackberry)
Control: Destroy fallen leaves in autumn. Spray with Witches’ broom, caused by Sphaerotheca
chlorothalonil, chlorothalonil + fenarimol, or mancozeb 2 to phytoptophila and eriophyid mites
The following are reported to be resistant or tolerant to fire Control: No practical control for affected trees. C.
blight: C. adpressus praecox, C. adpressus praecox ‘Boer’, C.
sinensis (Chinese hackberry) is resistant.
apiculatus, C. bacillaris, C. dielsiana var. elegans, C. distica, C.
francheti, C. harroviana, C. microphylla, C. neweryensis, C.
CERCIS (redbud)
nitens, C. salicifolius repandens ‘Emerald Spray’, C. simonsi.
Botryosphaeria canker
Control: Prune and destroy affected branches when CRATAEGUS (hawthorn)
foliage is dry. Control borers and avoid other injuries.
Fabraea leaf spot
Control: Destroy or compost fallen leaves. Spray as suggested under ALL SPECIES when leaf buds open and Verticillium wilt
repeat 10 and 20 days later. Additional applications may be Control: See suggestions under ALL SPECIES.
necessary during wet seasons. Plant resistant hawthorns suchas cockspur (C. crusgalli), Washington (C. phaenopyrum), CORNUS (dogwood)
Toba (C. mordenensis cv. Toba), or Lavalle’s (C. lavallei).
Botrytis flower and leaf blight
Control: Disease is serious only in wet years. If wet Fire blight
weather occurs during bloom, spray once with thiophanate- Control: See suggestions under MALUS. Do not use Discula anthracnose (lower branch dieback)
Rusts, caused by Gymnosporangium spp.
Control: Prune diseased branches back to sound wood Control: Eliminate nearby red cedar and common and destroy them. Remove epicormic shoots along trunk and juniper to whatever extent practical. Spray with triadimefon, limbs. Rake up and destroy fallen leaves. Avoid trimmer and chlorothalonil, mancozeb + thiophanate-methyl, or mower wounds and other unnecessary injuries. Maintain chlorothalonil + fenarimol. Begin spray schedule when vigor by applying mulch; water during dry periods. Do not orange rust masses develop on cedars (April through May).
transplant dogwood trees from the wild. Resistant dogwoods Make 3 or 4 applications at 7- to 10-day intervals. The include: C. kousa, C. racemosa, C. canadensis. For fungicide Washington thorn (C. phaenopyrum) and the cockspur thorn suggestions, see under ALL SPECIES, and begin ELEAGNUS (Russian olive)
Fungal twig blights and cankers
Canker, dieback
Control: Prune diseased branches back to sound wood Control: Prune out and destroy infected branches.
and destroy them. Maintain vigor by mulching; water duringdry periods.
EUONYMUS
Crown gall
Phytophthora crown canker
Control: Pretreat cuttings or liners with Galltrol-A or Control: Avoid mechanical injuries, especially to the Norbac 84. Destroy heavily infected plants. Prune out and lower trunk and roots. Remove discolored wood down to destroy galls on savable plants. Disinfest tools between cuts.
heartwood if necessary and healthy wood for 1.5 inches Apply Gallex to exposed galls. Plant crown gall-resistant around the edge of the canker. Control borers and treat all plants in the following genera: Berberis, Buxus, Carpinus, borer wounds like cankers. Trees with cankers that encircle Catalpa, Cedrus, Cephalotaxus, Cryptomeria, Fagus, Ginkgo, more than one half the stem should be removed and the area Ilex, Koelreuteria, Larix, Liriodendron, Magnolia, Mahonia, not replanted with dogwoods for several years unless the soil Nyssa, Picea, Pinus, Pseudolarix, Tamarix, Taxodium, Tilia, is fumigated. Where losses have occurred in nurseries, and Tsuga. Euonymus alatus is resistant.
fumigate the soil before planting. Provide good soil drainage.
Metalaxyl, used as a soil drench, will suppress crown canker.
Powdery mildew
Powdery mildew
Control: See suggestions under ALL SPECIES. Apply fungicide weekly beginning when disease symptoms first Control: See suggestions under ALL SPECIES.
Septoria and other fungal leaf spots, spot anthracnose
Control: Sprays ordinarily are not necessary. If disease FORSYTHIA
was severe the previous year and spring conditions are wet, Phomopsis gall
see fungicides suggested under ALL SPECIES, and apply Control: Prune out affected branches.
sprays at budbreak and 10 and 20 days later.
FRAXINUS (ash)
COTONEASTER
Anthracnose and other leaf spots
Fire blight
Control: See suggestions under ALL SPECIES.
Control: See suggestions under MALUS.
GLEDITSIA (honeylocust)
J. virginiana—‘Aurea’, ‘Berg’s Rust Resistant’, ‘Blue Leaf spots
Fountain’, ‘Globosa’, ‘Hillspire’, ‘Kosteri’, Control: Rake up and destroy fallen leaves.
‘Pseudocupressus’, ‘Primidalis’, ‘Tripartita’, ‘Venusta’.
Powdery mildew
Kabatina tip blight (the most damaging tip blight in
Control: No need to control this disease.
Kentucky)
Control: Prune out infected shoots. Chemical controls Thyronectria canker
have not been developed. Plant disease-tolerant cultivars Control: Avoid injuries; alleviate stressful growing conditions. Cultivars ‘Shademaster’, ‘Holka’, and ‘Imperial’ Juniperus chinensis—‘Ames’, ‘Aurea Gold Coast’, ‘Columnaris Hetzii’, ‘Hetzii Glauca’, ‘Keteleeri’, ‘Maney’,‘Mountbatten’, ‘Perfecta’, ‘Pfitzeriana’, ‘Pfitzeriana aurea’, ILEX (holly)
‘Robusta Green’, var. sargentii ‘Viridis’, sargentii ‘Glauca’, Black root rot
‘Saybrook Gold’, ‘Spartan’, ‘Winter Green’; Control: Practice strict nursery hygiene and sanitation.
J. communis—‘Hornbrooki’, ‘Hibernica’; Exclude the pathogen from the nursery by using disease-free J. horizontalis—‘Bar Harbor’, ‘Marcellus’; stock plants. Avoid use of unsterilized agricultural soils.
J. procumbens—‘Nana’, ‘Variegata’; Promote good plant growth. I. aquifolium and I. cornuta are J. scopulorum—‘Sutherland’;J. virginiana—‘Blue Fountain’, ‘Prostrata Glauca’.
Fungal leaf spots
Control: Rake up and destroy fallen leaves.
Phomopsis tip blight
Control: If possible, prune out and destroy infected JUGLANS (walnut, butternut)
shoots. Avoid overhead irrigation. Rogue and destroy Fungal leaf spots
infected plants when disease is first seen in young plantings.
Control: Destroy fallen leaves. Spray as suggested under Spray with mancozeb, thiophanate-methyl, or mancozeb + ALL SPECIES 3 times at 2-week intervals, starting when thiophanate-methyl plus a spreader-sticker at 2-week intervals throughout the growing season.
Use disease-resistant junipers such as: JUNIPERUS (juniper, red cedar)
Juniperus chinensis—‘Femina’, ‘Hetzii’, ‘Iowa’, ‘Keteleeri’, Cedar-apple, cedar-hawthorn, and cedar-quince
‘Pfitzeriana’, ‘Pfitzeriana aurea’, ‘Robusta’, var. sargentii, rusts, caused by Gymnosporangium spp.
sargentii ‘Glauca’, ‘Saybrook Gold’, ‘Shoosmith’, ‘Spartan’; Control: Do not plant near flowering crabapple, J. communis—‘Ashfordii’, ‘Aureo-spica’, var. depressa, hawthorn, quince, and similar plants. Manual removal of ‘Hibernica’, ‘Hulkjaerhus’, ‘Prostrata aurea’, ‘Repanda’, galls and infected twigs in early spring may be practical where infection is light. Use disease-resistant varieties such as: J. conferta—‘Blue Pacific’, ‘Emerald Sea’ J. horizontalis—‘Blue Mat’, ‘Depressa’, ‘Depressa aurea’, J. chinensis—‘Ames’, ‘Blue Mountain’, ‘Blue Point’, ‘Douglasii’, ‘Prince of Wales’, ‘Procumbens’; ‘Columnaris Hetzii’, ‘Femina’, ‘Fortunei’, ‘Fountain’, ‘Grey J. sabina—‘Broadmoor’, ‘Knap Hill’, ‘Skandia’; Owl’, ‘Hetzii’, ‘Japonica’, ‘Keteleeri’, ‘Leeana’, ‘Maney’, J. scopulorum—‘Silver King’, ‘Campbellii’; ‘Mas’, ‘Mountbatten’, ‘Oblonga’, ‘Pedula’, ‘Perfecta’, J. squamata—var. fargesii, ‘Meyerii’, ‘Prostrata’, ‘Pumila’; ‘Pfitzeriana’, ‘Pfitzeriana Compacta’, ‘Pfitzeriana Glauca’, J. virginiana—‘Tripartita’.
‘Plumosa Aurea’, ‘Pyrimidalis’, ‘Robusta Green’, ‘sargentii’,sargentii ‘Variegata’, sargentii ‘Wateri’, ‘Winter Green’; KALMIA (mountain laurel)
J. communis—‘Aurea’, ‘Aureo-spica’, ‘Cra Covia’, var.
Fungal leaf spots
depressa, depressa ‘Aurea’, ‘Hibernica’, ‘Oblonga Pendula’, Control: Hand pick infected leaves and prune infected ‘Saxatilis’, ‘Saxatilis Pallas’, ‘Suecica’, ‘Suecica Nana’; shoots; destroy or compost fallen leaves. If disease has been J. horizontalis—‘Admirabilis’, ‘Adpressa’, ‘Argenteus’, severe, spray as suggested under ALL SPECIES at budbreak ‘Depressa’, ‘Douglasii’, ‘Eximius’, ‘Filicinus’, ‘Glomerata’, ‘Lividus’, ‘Petraea’, ‘Plumosa’, ‘Variegata’, ‘Wiltonii’;J. procumbans; KOELREUTERIA (goldenrain tree)
Nectria canker
J. sabina—‘Broadmoor’, ‘Fastigiata’, ‘Knap Hill’, ‘Skandia’, Control: Prune back to sound wood. Fertilize and water J. scopulorum—‘Medora’, ‘Moonglow’, ‘Sparkling Sky-rocket’, ‘Wichita Blue’; Verticillium wilt
J. squamata—‘Albo-variegata’, var. fargesii, ‘Meyerii’, Control: See suggestions under ALL SPECIES.
LIRIODENDRON (tulip poplar)
The following flowering crabapple cultivars are Verticillium wilt
moderately to highly resistant to powdery mildew, scab, fire Control: See suggestions under ALL SPECIES.
blight leaf spot, and rust (see also U.K. CES publication ID-68 “The Flowering Crabapple”): Powdery mildew
‘Adams’, bacatta ‘Jackii’, ‘Beverly’, ‘Bob White’, ‘Candied Control: No need to control this disease.
Apple’, ‘Christmas Holly’, ‘David’, ‘Donald Wyman’,‘Henningii’, ‘Jewelberry’, ‘Liset’, ‘Mary Potter’, ‘Molten MAGNOLIA
Lava’, ‘Ormiston Roy’, ‘Profusion’, ‘Red Jewel’, ‘Red Leaf spots
Splendor’, ‘Robinson’, sargentii, ‘Sentinel’, ‘Silver Moon’, Control: If disease has been severe, spray as suggested ‘Strawberry Parfait’, ‘Sugar Tyme’, ‘Velvet Pillar’, ‘White Angel’, ‘White Cascade’, ‘Winter Gold’, hunnanensis‘Veitchii’, zumi ‘Calocarpa’.
MALUS (apple, flowering crabapple)
See list of disease-resistant varieties and cultivars below.
PICEA (spruce)
Cytospora canker
Fire blight
Control: Remove and destroy all diseased branches (do Control: Avoid use of high nitrogen fertilizer. Cut out not prune in wet weather); disinfest tools between cuts.
cankers and blighted branches between November and Chemical control measures are not available.
March when tree is dry, making cuts below the visible limitsof infection. Unless done when symptoms are first just Rhizosphaera needlecast
visible, pruning cuts done April through October have little Control: Sprays are normally not needed. This disease is value in fire blight control and in fact may spread the disease.
most often found on trees weakened by other factors.
Once symptoms are obvious, allow tree defenses to stop the Chlorothalonil applications in early and late June may help.
spread of disease. Remove worthless pear, apple, quince, andsimilar plants from the vicinity. Use MARYBLYT computer PIERIS (andromeda)
program to time sprays in the nursery during bloom.
Otherwise, spray with streptomycin when 25 percent ofblossoms are open and again when 75 percent of blossoms are PINUS (pine)
open. To prevent injury, if temperatures are above 65°F, use Gall rusts of 2- and 3-needle pines (eastern gall rust,
fixed copper instead of streptomycin. Avoid use of western gall rust)
Control: In nurseries, cull seedlings with stem swellings.
In plantations, cut off branch galls and rogue heavily galled Rust, caused by Gymnosporangium spp.
trees in early spring. Apply mancozeb or triadimefon once Control: Eliminate nearby red cedar and common when yellow pustules erupt through bark on galls.
juniper where possible, or remove and destroy cedar rustgalls and rust-infected juniper twigs. Spray with fenarimol, White pine decline, a non-infectious disease
propiconazole, chlorothalonil + fenarimol, triadimefon, Control: No control for established trees. Provide a mancozeb, or mancozeb plus thiophanate-methyl. Make 3 planting site having acid soil with little clay. Avoid soil applications at 10-day intervals beginning when orange rust compaction and tree injuries. Remedial sulfur applications to masses develop on junipers (April through May).
Powdery mildew
White pine root decline, a fungal disease
Control: Provide a sunny, well-ventilated planting site.
Control: Remove and destroy infected trees. Choose Use disease-resistant types. Prune away shading vegetation.
well-drained planting sites. Control wood boring insect For fungicide suggestions, see under ALL SPECIES.
Scab
Needlecast diseases of 2- and 3-needle pines
Control: Rake up and destroy all fallen leaves and fruits Control: In nurseries, spray with chlorothalonil, ferbam, in the fall. During the growing season, spray: chlorothalonil, or mancozeb plus a spreader-sticker monthly from mid-April fenarimol, propiconazole, chlorothalonil + fenarimol, through October. Avoid planting highly susceptible strains of mancozeb, thiophanate-methyl, or mancozeb + thiophanate- Scots pine such as Spanish and French Green.
methyl at pink bud and at petal-fall, plus 2 more applications In plantations and landscapes: Plant on slopes when at 10-day intervals to control primary infections. Apply possible. Space trees and control weeds for good air before rain if possible, and extend the schedule during rainy circulation around low branches. Avoid susceptible varieties seasons. Use disease-resistant crabapples.
of Scots pine; if in doubt, use long-needle varieties. Rogueheavily infected source trees. Trim off and destroy lowest Frogeye leaf spot (black rot)
branches to promote air circulation. If disease occurs, spray Control: Eliminate dead twigs and branches.
four times at monthly intervals beginning July 1(Lophodermium needle cast) or mid-April through June (for brown spot needle blight or Naemacyclus needle cast). Use Spray with captan, chlorothalonil, vinclozolin, or chlorothalonil, mancozeb, ferbam, or bordeaux mixture propiconazole as blossoms open and again 10 days later.
PYRACANTHA (firethorn)
Needle rust of 2- and 3-needle pines (Coleosporium)
Fire blight
Control: Goldenrod and aster plants are alternate hosts.
Control: See under MALUS fire blight control.
In plantations, mow or otherwise control these weedsannually before August.
Scab
Control: Spray with benomyl plus a spreader-sticker; Diplodia tip blight of 2- and 3-needle pines
chlorothalonil, thiophanate-methyl, mancozeb, mancozeb + Control: Prune and destroy affected cones, twigs, and thiophanate-methyl, or chlorothalonil + fenarimol at full branches during dry weather in autumn. Spray with bloom and 2 and 4 weeks later. The Yunan firethorn, P.
thiophanate-methyl at bud break, as candles are beginning to crenato-sessata, is reported to be resistant. Hybrids resistant elongate, and when needles are emerging from needle to both scab and fire blight include ‘Apache’, ‘Fiery Cascade’, ‘Mohave’, ‘Navaho’, ‘Pueblo’, ‘Shawnee’, Pine wilt nematode
Control: Remove and destroy affected trees.
PYRUS (pear)
PLATANUS (plane tree and sycamore)
Fire blight
Anthracnose
Control: See MALUS fire blight control. The Bradford, Control: Prune out infected twigs and branches. Rake up Aristocrat, and other flowering pear cultivars are susceptible and destroy fallen leaves. See fungicide suggestions listed for to the disease yet not normally heavily infected.
ALL SPECIES. Make a first application before trees break bud, QUERCUS (oak)
a second at bud break, and a third when leaves are expanding.
Trees can also be protected by thiabendazole injections.
Anthracnose
Control: See anthracnose under ALL SPECIES.
POPULUS (poplar, aspen, cottonwood)
Dieback, decline
Fungal cankers
Control: Keep trees well-watered, especially through Control: Mulch and water trees as needed. Avoid dry periods from May through July. Control of defoliating wounding. Prune out and destroy infected branches during insects is important for prevention of dieback and decline.
dry weather. Destroy severely affected trees. Do not plant Alleviate soil compaction in the root zone. Prune out dead Lombardy poplars. The Japan poplar, Populus maximowczii, and dying branches to improve tree’s appearance.
is reported to have some resistance to cankers.
Taphrina leaf blister
Leaf rust
Control: Spray once before bud swell with mancozeb, Control: Spray triadimefon in early summer just before chlorothalonil, or chlorothalonil + fenarimol.
disease is expected and again 2 weeks later.
Actinopelte leaf spot
PRUNUS (cherry, flowering cherry, peach,
Control: Normally, there is no need to control this flowering almond)
disease. Rake up and destroy fallen leaves. Propiconazole Black knot
Control: Prune away and destroy knotted twigs, and Armillaria shoestring root rot
excise knots on large limbs when trees are dormant. Spray Control: This disease most frequently affects trees with thiophanate-methyl when dormant and at pink bud, full weakened by other agents. No control.
Bacterial leaf scorch, Xylella
Crown gall
Control: No effective control.
Control: See EUONYMUS disease control. For galls on established trees, use Gallex according to label instructions.
Powdery mildew
Control: Usually there is no need to control this disease.
Coccomyces leaf spot
Control: Rake up and destroy fallen leaves. Spray with Bacterial wetwood
propiconazole or captan at petal fall, plus 2 more applications at 2-week intervals, plus a single application after fruit drop ifneeded.
RHODODENDRON (azalea, rhododendron)
Azalea gall
Monilinia shoot blight (brown rot)
Control: Pick and destroy galls.
Control: Prune out and destroy infected twigs if possible.
Botryosphaeria canker and dieback
Powdery mildew
Control: Prune and destroy infected parts disinfesting Control: See under ALL SPECIES powdery mildew tools carefully between cuts. Avoid adverse growing control. Resistant lilacs (non-vulgaris types) include: S.
conditions, i.e., drought, freezing, etc. Hybrids reported to be diversifolia, S. emodi, S. julianae, S. meyeri, S. mycrophylla, resistant include: ‘Boursalt’, ‘Chionoides White’, S. mycrophylla superba, S. oblata var. dilatata, S. patula, S.
‘Cunningham’s White’, ‘English Roseum’, ‘Le Bar’s Red’, persica, S. reflexa, S. reticulata, S. swegiflexa, S.
‘Roseum 2’, ‘Sweet Simplicity’, ‘Wissahickon’.
sweginzowii, S. villosa, S. yunnanensis.
Phytophthora dieback
THUJA (arborvitae)
Control: Avoid planting near lilacs. Prune and destroy Tip blights
infected twigs. Reduce shade if possible. As new leaves Control: See under JUNIPERUS tip blight disease control.
appear, spray with mancozeb or chlorothalonil + fenarimol,making 2 applications 10 to 14 days apart. Applications of ULMUS (elm)
metalaxyl (soil drench) or fosetyl-Al may help.
Dutch elm disease
Fungal leaf spots
Control: Where infected elms are allowed to grow Control: Hand pick infected leaves if possible. Spray at nearby, the chances of preserving a susceptible elm are poor.
budbreak and 10 and 20 days later with thiophanate-methyl, Effective control is best done on a community-wide basis.
1. Eliminate, if possible, all potential beetle-breeding
elm material within 1,000 feet of trees to be protected. This Root rot and wilt, caused by Phytophthora and other
material includes diseased, weak, recently cut, killed, or fungi
broken elm trees or parts of trees including firewood. Such Control: Plant only in soils with good drainage. Avoid material should be burned, buried, or debarked, and the bark overwatering. Adjust soil Ph to between 4.0 and 4.5 by burned or buried. This sanitation is most important in and amending with acid peat or sulfur. Apply soil drench immediately adjacent to trees to be protected. Without fungicides such as propamocarb, metalaxyl, ethazole, or sanitation, the other suggestions listed here are not very helpful.
2. Make dormant application (March or April) of
ROSA (rose)
methoxychlor or chlorpyrifos insecticide for control of elmbark beetles.
Black spot
Control: Spray with chlorothalonil, folpet, fenarimol, 3. Prune out DED-infected branches. Pruning is
ferbam, maneb, captan, mancozeb, propiconazole, ziram, or sometimes effective if symptoms are detected while confined mancozeb + thiophanate-methyl at 7- to 14-day intervals to a small branch and the large branch bearing the small one beginning as leaves expand. Shorten intervals during wet weather. Some rose varieties are sensitive to chlorothalonil.
4. Inject Arbotect 20-S, Lignasan (Correx, Elmpro),
Resistant hybrid tea roses include: ‘Carla’, ‘Cayenne’, Fungisol, or Phyton 27 into the lower trunk and root flare for ‘Duet’, ‘Electron’, ‘First Prize’, ‘Granada’, ‘Miss All protection or therapy. Follow manufacturer’s instructions for American Beauty’, ‘Mister Lincoln’, ‘Pascali’, ‘Peace’, application. Combine eradicative pruning (step 3) with ‘Pink Peace’, ‘Portrait’, ‘Pristine’, ‘Proud Land’, ‘Sutter’s therapeutic treatments. These should be made as soon as Gold’, ‘Tiffany’, ‘Tropicana’.
symptoms are seen, but will seldom be effective in trees that Resistant floribunda/grandiflora roses include: ‘Angel became infected the previous year or that show symptoms in Face’, ‘Betty Prior’, ‘Carousel’, ‘Europeana’, ‘First Edition’, more than 5 percent of the crown. Fungicide injections made ‘Gene Boerner’, ‘Ivory Fashion’, ‘Montezuma’, ‘Pink the year before may protect trees from the disease.
Parfait’, ‘Prominant’, ‘Queen Elizabeth’, ‘Razzle Dazzle’, ‘Red 5. Prevent root graft transmission of DED by applying
Gold’, ‘Rose Parade’, ‘Sonia’, ‘Sun Sprite’, ‘The Fairy’.
vapam to the soil in 3/4" x 18" holes 6 inches apart midwaybetween diseased and healthy trees at a rate of 1/4 cup of Crown gall
dilute solution (1 part Vapam to 3 parts water) per linear foot.
Control: See under EUONYMUS disease control.
Seal by tamping. This treatment should also prevent root graft Powdery mildew
transmission of phloem necrosis. If phloem necrosis is Control: See suggestions under ALL SPECIES. Select involved, treat at two sites: one between diseased tree and fungicides that also control black spot.
nearest healthy tree and one between first and second healthytrees. Digging a trench 18 inches deep and a few inches wide Brown canker, stem canker, graft canker
between trees will accomplish the same as vapam treatments.
Control: Prune out and destroy infected canes.
6. The herbicide cacodylic acid can be used to kill diseased
elm trees which attract and “trap” bark beetles. The beetles fail to SYRINGA (lilac)
mature in such trees and are then lost as a vector source.
Bacterial blight
In general, native elms are susceptible to Dutch elm Control: Prune out and destroy dead twigs.
disease and phloem necrosis; elms of European origin vary in susceptibility to Dutch elm disease; elms of Asiatic origin areresistant. The yellows pathogen normally is not a problem inEuropean and Asiatic elms. The following can be grown:Chinese elm (U. parvifolia), Scots elm (U. glabra), Buismanelm (U. hollandica ‘Christine Buisman’), and Groeneveldelm (U. hollandica ‘Groeneveld’). Additional resistantcultivars such as ‘Lobel’, ‘Dodoens’, ‘Plantyn’, ‘Clusius’,and ‘Columella’ are available. Hybrid clones with Asian orEuropean parentage ‘Dynasty’, ‘Frontier’, ‘Homestead’,‘Jacan’, ‘New Horizon’, ‘Ohio’, ‘Pathfinder’, ‘Pioneer’,‘Prospector’, ‘Regal’, ‘Sapporo Autumn Gold’, ‘Thompson’,and ‘Urban’ Elm have been bred for disease resistance.
‘American Liberty’ ‘Independence’, and ‘Washington’American elms are considered tolerant to DED but not to elmyellows. Consult nursery catalogs for a full account of thecharacteristics of disease-resistant elms.
Disease-resistant elms in the vicinity of susceptible trees must be included in sanitation programs since elm barkbeetles breed in dead or dying parts of all kinds of elms.
Yellows, also known as phloem necrosis
Control: See controls listed for Dutch elm disease.
Bacterial wetwood and slime-flux
Control: Install drainpipes to keep fluid from running down the bark. Pipes can be of threaded metal or stiff plastic.
If plastic is used, coat the inside of the hole with grafting waxbefore fitting the tube, and seal at the surface with graftingwax. Plastic can be cut to desired length after fitting.
VIBURNUM
Powdery mildew
Control: See ALL SPECIES powdery mildew control.
Resistant types include V. burkwoodii ‘Mowhawk’ and V.
carlcephalum ‘Cayuga’.
Additional References
Jones, R.K., ed. Diseases of Woody Ornamental Plants and
Their Control in Nurseries. North Carolina State University
Cooperative Extension Service.
Pirone, P.P. Diseases and Pests of Ornamental Plants. JohnWiley & Sons.
Sinclair, W.A., Lyon, H.H., and Johnson, W.T. Diseases ofTrees and Shrubs. Cornell University Press.
Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability, or national origin.
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, C. Oran Little,Director of Cooperative Extension Service, University of Kentucky College of Agriculture, Lexington, and Kentucky State University, Frankfort.
Issued 7-89; Revised/Printed 7-96, 2000 copies; 10000 copies to date.

Source: http://www.garlicworld.co.uk/library/books/id88.pdf