| HOST PLANT |
DISEASE |
SYMPTOMS |
MANAGEMENT |
Ash, Green
Fraxinus pennsylvanica |
Anthracnose, Apiognomonia errabunda |
Initially, tiny purple/brown spots on young leaves. Spots
enlarge, coalesce and form brown blotches. Leaf distortion common. Young
shoots may be killed back. Defoliation may be severe. |
Remove fallen leaves and dead twigs and branches,
especially on young trees.
CHEMICAL: Chlorothalonil, mancozeb,
thiophanate-methyl or zyban beginning at budbreak. |
| Ash yellows, caused by a phytoplasma (mycoplasma-like
organism) |
Severe reduction in growth,
chlorotic leaves in tufts at end of branches along with dieback. Witches’
brooms may form on the trunk. |
Maintain tree vigor to prolong life. Remove as they become
hazard trees.
CHEMICAL: None.
REFERENCE: Ash Yellows in
Minnesota. |
| Heart rot, Perennoporia fraxinophila |
Crumbly, soft decay in trunks and larger limbs. Groups of
bract-shaped, grayish-white perennial conks appear along the infected
branches and trunk. |
Remove dead and dying branches. Avoid mechanical injury.
CHEMICAL: None. |
| Sulfur shelf heart rot, Laetiporus sulfureus |
Brown cubical rot of roots, butt and trunk with sunken
elongate cankers on the surface. Bright yellow to orange, fleshy fungal
reproductive structures appear in summer and fall. |
Proper pruning: avoid mechanical injury.
CHEMICAL:
None. |
| Verticillium wilt, Verticillium dahliae |
Acute or chronic symptoms may appear anytime during the
growing season. Chronic: small, chlorotic leaves, leaf scorch, slow
growth, abnormally heavy seed crop, shoot dieback. Acute: leaf
curling or scorching, abnormal red or yellow color, partial defoliation,
wilting, and branch dieback, plant death. Symptoms often on only one part
of the tree or shrub. |
This wilt is soilborne; replace
with resistant tree species. Keep infected trees well watered and
fertilize with a fertilizer high in potassium. Remove dead branches.
CHEMICAL:
None.
REFERENCE: Verticillium Wilt of Trees and Shrubs
|
