Go to Mizzou without going to Mizzou
Instant access
Soil Testing
and Plant Diagnostic Services
MU affiliations
Other alliances
Plant Diagnostic Clinic
573-882-3019
Large,
irregular brown spots mostly along leaf margins. In rainy seasons, when the disease
is most severe, leaves drop prematurely. Collect and remove fallen leaves. Usually,
disease is not serious enough for fungicidal control, except in unusually wet
seasons or locations with severely restricted air circulation. Use chlorothalonil,
fixed copper compounds, mancozeb (some brands of mancozeb are labeled for white
ash only), quaternary ammonium compounds, or thiophanate-methyl.
Decline (various
causes) Trees lose large branches over several years and may die. No one cause has been identified. It is probably a complex of insect, disease and environmental problems, such as moisture stress and freeze injury. A close association between ash decline and ash yellows, caused by a phytoplasma, has been reported. Follow standard horticultural practices for pruning, fertilizing and watering. If specific insect or disease problems are recognized, appropriately treat each specific problem.
Floral damage caused by ash flower gall mite.
Ash flower gall during the dormant season
Male flower clusters become enlarged, distorted and woody. May persist on tree one or more years.
Does not affect tree vigor.
Leaf margins brown and dry up when water uptake is less than water need. May be due to drought, a xylem limited bac terium, Verticillium wilt or root diseases associated with decline. Mycophaerella leaf spot may resemble this.
Water deeply during dry periods.
Irregular browning and blotches usually occurring in the summer or fall.
In fall, clean up fallen leaves.
Leaves may be mottled, stippled, distorted or have irregular brown spots. Black excrement may appear on either surface. The feeding of these insects has little effect on plant vigor.
Leaf scorch, dieback of branches and long-term decline. No fungicidal control is possible. Remove severely affected plants. Replant only with resistant species.
Decline, premature death, witch's broom, suckering from limbs and trunk and leaves and twigs stunted are increased evidence of freeze injury. Remove affected trees.
Updated 3/2/07
On this page
Related page
On this site
Contact
