AshAsh dieback, decline (general)1Fraxinus americanaF. pennsylvanica | Drought periods | Bark canker fungi: Cytophoma pruinosa Fusicoccum sp. |
Reduced terminal and radial growth Death of terminal buds and branches Thin, “tufted” crowns Sometimes, early fall coloration Death of trees Reddish-brown to orangeyellow cankers on branches and stems
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Forest: little can be done, salvage Urban: water when feasible, possibly reduce water loss by mulching
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Dieback (general, near coastal salt marshes with Spartina grass hostsFraxinus spp. | Defoliation by rust fungus, Puccinia peridermiospora | None | Dieback occurs the season following severe defoliation/refoliation
Death of terminal buds and branches Thin, “tufted” crowns Death of some trees
| Most trees will recover unless defoliation is repeated or coincides with drought. |
Beech Beech bark disease (general in east through NY and mid-PA; northeastern WV.) Fagus grandifolia F. syivatica | Attack by the beech scale, Cryptococcus fagisuga | Bark canker fungi: Nectria coccinea var. faginata; N. galligena |
Thinning chlorotic crowns Presence on bark, especially in roughened spots, of white “wool-like” wax of the beech scale Presence on bark previously infested by scale of small, red fruiting bodies of Nectria fungi Weeping exudates may precede or accompany the fruiting bodies Bark is killed, and trees die. Some trees snap off where bark dies and wood decays
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Forest: salvage trees when scale populations become high and Nectria is abundant. Trees free from scale (resistant) should be favored Urban: treat individual trees with dormant sprays or chemical fungicides registered for use against the beech scale
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Dogwood Lower branch dieback, anthracnose (southern New England, northern midAtlantic states; urban, woodlands)Cornus florida, native and cultivars | Suspected: series of unusually wet springs, followed by summer dry periods | Leaf and twig fungus (Discula sp. Gnomonia sp.) of anthracnose type |
Blighted leaves in early spring Dieback of buds, twigs and branches beginning on lowermost parts of tree Development of branch cankers Water sprouts from near branch cankers — these in turn are killed, trees die
| Not yet known |
Maple Maple decline (general;forest) Acer saccharum | Defoliation by a number of insects including:
saddled prominent forest tent caterpillar maple webworm green stripped mapleworm
| The shoestring root rot fungus, Armillaria mellea, and twig fungus, Stegonosporum sp. | Death of buds, terminal twigs and branches the year after severe defoliation Thin “tufted” crowns New foliage on sprouts Continued decline and death of some trees White fungus “fans” often present beneath bark of roots and bases of dead and dying trees
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Forest: prevent defoliation, salvage if significant portion of crown is killed Urban: prevent defoliation
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“Roadside” maple decline2 A. saccharum | Deicing salts, and/or construction damage to roots | Many twig, root and stem decay fungi |
Crown dieback, especially on road side of tree Leaves show fall colors early and drop Leaves may also show inter- veinal necrosis (scorch) Dieback progresses over years, trees eventually die
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Avoid use of deicing salt when feasible Plant replacement trees where brine will not run over roots
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“Urban” maple decline (Wisconsin) saccharum | Suspect stress of planting trees too deeply in heavy soils, or settling of trees after planting | Soil borne canker fungi: Fusarium sp.; Phytophtho. citricola |
Leaves small, show fall colors early and drop Twigs and branches die back c) Rootlets die Bark at tree base loosens to show discoloration and decay of underlying wood Trees die one to several years after first symptoms
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Improve soil drainage Insure planting is shallow
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Oak Oak decline (general) Quercus spp. | Defoliation by any of several insects including:
gypsy moth leaf rollers and tiers canker worms webworms, etc., and sometimes exacerbated by periods of water shortage
| The shoestring root rot fungus, A. mellea; and the twolined chestnut borer, Agrilus bilineatus |
Dieback of terminal buds and branches in next season New foliage produced on sprouts in the crown and on the bole — crowns “tufted” Progressive dieback; mortality White fungus “fans” beneath bark (see Maple decline forest) “D”-shaped holes in bark and meandering insect galleries on outer sapwood beneath barka)
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Forest: prevent defoliation: salvage Urban: as above; supply water during refoliation if feasible. Possibly spray tree trunks to prevent attack by borers
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Oak decline (midwest; urban)
Q. rubra Q. alba Q. macrocarpa
| Adverse soil changes, including alkalinization, caused by various urban practices and disturbance | The shoestring fungus, A. mellea, and the borer, A. bilineatus |
Deterioration of fine feeder root system Dieback and decline of upper crowns progressing sometimes until the tree dies Signs of A. mellea and A. bilineatus
| Keep “wooded” areas as natural as possible; avoid watering with hard water, runoff from concrete surfaces, fertilizing with limebased fertilizers, mixing of soil by construction, grading, etc. Mulch and reduce grass competition |
Oak decline (midwest; general)
| Periods of unusual springtime wetness in areas where soil overlies dense clays | The shoestring fungus, A. mellea, and the borer, A. bilineatus |
Rapid dieback and decline of mature and overmature trees Signs of A. mellea and A.bilineatus
| None known |
Pin oak canker dieback3 (mid-Atlantic states; urban)
| Pruning wounds made during drought | Bark canker fungus: Endothia gyrosa |
Dieback of lower branches, especially those from which smaller ones have been pruned Death of some trees Orange-red to brown-black fruiting pustules on dead bark
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Forest: not a problem Urban: water during drought periods. Avoid pruning during dry times.
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