Boxwood Diseases
Gary W. Moorman, Professor of Plant Pathology
|
Disease |
Symptoms |
Pathogen/Cause |
Management |
|---|---|---|---|
|
Decline |
Stunted growth and dieback occur. Young foliage turns grayish green or bronze and finally straw colored. Old leaves fall prematurely. Middle or top branches die. Sunken cankers form at the soil line or on branches in the crotches where dead leaves accumulate. Wood under the sunken canker is blackened. |
Attack by various fungi and nematodes add to damage from winter injury and stress on plants, especially those in poorly drained sites. |
Protect plants from winter injury and other stresses. Prune dead branches well below cankered areas. Remove dead leaves accumulated among the branches. |
|
Leaf burn |
Leaf tips and margins yellow and redden as leaves fall prematurely. |
Water stress and low temperature. |
Protect shrubs from drought and drying winds in the autumn and winter. |
|
Leaf spot |
Straw-yellow leaves are dotted with small, black fungal fruiting structures. |
Macrophoma candollei |
Only leaves weakened by winter injury are infected. Protect plants from wind, salt spray, and salt runoff. |
|
Nematodes |
Growth is stunted, leaves have a bronzed appearance, and the shrub is in decline. Small roots have small brown dead areas which enlarge to engulf the entire root ends. |
Pratylenchus |
There are no adequate controls once the plant is infected. If a plant is removed, do not replace it with a nematode-susceptible plant unless the site is thoroughly fumigated and aerated first. |
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Issued in furtherance of Cooperative Extension work, Acts of Congress, May 8 and June 30, 1914, in cooperation with the U. S. Department of Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.
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