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European Pear (Pyrus communis): Fruit distortion due to true bug feeding damage Fraser Photinia (Photinia x fraseri): defoliation by Leaf Spot (Diplocarpon mespili)

Birch (Betula sp.): gallForsythia (Forsythia sp.): Stem Gall (Psudomonas savastanoi) Oak (Quercus sp.): mite galls

Alder (Alnus rubra): cankers (undetermined cause) Peach (Prunus persica): dieback and canker

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Tomato (Lycopersicon esculentum): rot caused by Late Blight (Lycopersicon esculentum)

Kousa dogwood (Cornus kousa)Plant decline

Goldenchain tree (Laburnum x watereri):aphids

Signs: evidence of the actual causal agent

Diseases:• fungal fruiting bodies

• fungal mycelia• bacterial slime (more later…)

Other…• rodent mounds/holes

• slug trails

Insects:• the insect itself

• boring holes or tunnels• sawdust• frass…

Apple (Malus domestica): Crane fly (Tipula sp.)

Sunflower (Helianthus annuus): Sclerotinia wilt (Sclerotinia sclerotiorum) Apple (Malus domestica): Rust (Gymnosporangium sp.)

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Incense-cedar (Calocedrus decurrens):Broom rust (Gymnosporangium libocedri) Big-leaf maple (Acer macrophyllum): Tar spots (Rhytisma punctatum)

Cherry (Prunus sp.): possible Bacterial canker damage (Pseudomonas syringae) Apple (Malus domestica): Leaf roller (species undetermined)

Rhododendron (Rhododendron sp.): Azalea Lace Bug (Stephanitis pyrioides)

Hebe (Hebe sp.): Meadow spittle bugs(Philaenus spumarius)

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Viburnum davidii: leaf notching due to root weevils Colorado Blue Spruce (Picea pungens): White Pine weevil (Pissodes strobi)

Cherry (Prunus sp.): leafroller activity Slug trails

Vole burrows

Some signs cannot be seen without magnification

Red raspberry (Rubus idaeus): RBDV

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‘Brooks’ Plum (Prunus domestica): possible Bacterial canker (Pseudomonas syringae)

Pear (Pyrus communis): Leaf spot-undetermined cause

• Plant Disease Control:• PNW Disease Management Handbook

http://pnwhandbooks.org/plantdisease/

• Insect Pest Control:• PNW Insect Management Handbook

https://pnwhandbooks.org/insect

• Weed Control:• PNW Weed Management Handbook

http://pnwhandbooks.org/weed/

Websites for home garden problems

Pesticide recommendations for homeowners

Common cultural and environmental problems inthe garden and how to recognize them

Neil BellOSU Extension ServiceMarion and Polk Counties

• Planting practices

Cultural causes of plant problems

• Herbicide injury

• Pruning injury

• Root damage

• Rootbound plants

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White-bark birch (Betula jacquemontii)

Root-bound plants

Fig (Ficus carica): circling roots

Deodar cedar (Cedrus deodara)

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European White Birch (Betula pendula)Western Juniper(Juniperus occidentalis)

Deodar cedar (Cedrus deodara)

Pruning problems

Rockrose (Cistus x hybridus)

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Oriental Arborvitae: Platycladus orientalis

Pesticide injury

Raspberry (Rubus idaeus): glyphosate damage Photo: B. Strik

Bearded Iris (Iris sp.):glyphosate damage

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Oak leaf Hydrangea (Hydrangea quercifolia): phenoxy herbicide damage

Pine (Pinus sp.)Phenoxy herbicide damage

Deodar Cedar (Cedrus deodara): phenoxy herbicide damage

Rose (Rosa sp.): acetic acid herbicide injury

Environmental causes of problems

• Cold Injury

• Wind/hail/lightning

• Water (too little or too much)

• Sun (too much or too little)

• Pollination problems

• Nutrient deficiencies

Cold Injury

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Cold injury results from:

• Unexpected frosts

• Winter low temperatures

Rare to see winter injuryto deciduous shrubs andtrees or conifers

Port Orford Cedar(Chamaecyparis lawsoniana)

Shrub dogwood (Cornus sericea ‘Kelseyi’)

Coyote brush (Baccharis pilularis) Mexican orange (Choisya ternata)

Marion trailing blackberry (Rubus ‘Marion’)Apple (Malus domestica)

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English yew (Taxus baccata): snow damage

Frost damage

Photos: B. StrikStrawberry (Fragaria x ananassa)

Pollination problems

Honeybee (Apis mellifera) on blueberry flowers (Vaccinium corymbosum) Zucchini (Cucurbita pepo)

Grape (Vitis sp.)

Too much or too little sun

Vine maple (Acer circinatum)

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Distinguish between excess sun (sunburn)and drought stress

Sunburn occurs when a plant, or plant partis exposed to too much sun and heat, evenif well-supplied with water

Drought stress occurs to any plant when soilwater becomes limiting

Sunburn can occur on leaves, flowers, fruit or stems…

Rhododendron: (Rhododendron sp.) Japanese barberry (Berberis thunbergii): yellow-foliaged cultivar

Hosta sp.: sunburn

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Flowering dogwood (Cornus florida): heat?

Sunburn on flowers

Mophead Hydrangea (Hydrangea macrophylla)

Sunburn on fruit

Red Maple (Acer rubrum)

Atlas Cedar (Cedrus atlantica ‘Glauca Pandula’): winter sunburn?

Lack of sun can cause problems…

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Flowering dogwood:(Cornus canadensis)

Flowering dogwood (Cornus florida)Mugo Pine:(Pinus mugo)

Too much or too little water

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Drought stress is dependent on:

• Inherent drought tolerance of plant

• Soil conditions (moisture, structure etc.)

• Irrigation (and it’s efficacy)

• Site exposure and aspect

• Weather conditions (temperature, wind)

Hebe sp.

• Drooping foliage

• Tip burn

• Brown areas on leaves

• Loss of older leaves

• Shoot dieback

Symptoms of drought stress

Pacific Dogwood (Cornus nuttalli) Red Alder (Alnus rubra): drought stress

Katsura tree:(Cercidiphyllum japonicum)

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Rhododendron (Rhododendron sp.)

Ponderosa PinePinus ponderosa

Douglasfir (Pseudotsuga menziesii)

Drainage Problems

Drainage problemsresult from:

• Topography

• Impervious soil

Leyland Cypress:(x Cupresssocyparis leylandii)

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Boysenberry (Rubus ‘Boysen’)

Raspberry (Rubus idaeus):Phytophthora root rot

(Phytophthora spp.)

Nutrient deficiencies in plants

Dicentra spectabilis ‘Gold Heart’

Major nutrients: Minor nutrients:

Also: salt toxicity….

Nutrients required by plants

Nitrogen (N)Phosphorus (P)Potassium (K)

Calcium (Ca)Magnesium (Mg)Sulfur (S)

Iron (Fe)Zinc (Zn)Manganese (Mn)Copper (Cu)

Molybdenum (Mo)Boron (B)Chlorine (Cl)

Base of plant – mobile (N, P, K, Mg)

Location of symptoms:

Top of plant – immobile (Ca, Fe, Mn, Zn, Cu, B)

Whole (mid) plant – partially mobile (S, Mo)

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Mobile nutrient: symptoms at plant base

Flowering plum (Prunus x blireana)

Mobile nutrient: Nitrogen deficiency

Japanese Fatsia (Fatsia japonica ‘Variegata’) Rhododendron (Rhododendron sp.): Nitrogen deficiency

Turf: Nitrogen deficiency

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Immobile Nutrient: Iron

Rhododendron (Rhododendron sp.): pH-induced Fe deficiency

Blueberry (Vaccinium corymbosum: pH-induced Fe deficiency Apple (Malus domestica): bitter pit

Immobile Nutrient deficiency in fruit: Calcium

Tomato (Lycopersicon esculentum):Blossom end rot

Salt toxicity

Winged Euonymus (Euonymus alatus): salt toxicity

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Wind

Hardy Kiwifruit (Actinidia arguta): scarred fruit

Hail

Highbush blueberry (Vaccinium corymbosum): hail damage

Apple (Malus domestica):Hail damage

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Douglasfir (Pseudotsuga menziesii): Lightning damage