|
|
Botrytis petal blight (fungus) |
Occurs in wet springs. Irregular brown areas on fading flowers and leaves. May be covered with gray mold in wet weather. |
Apply fungicide just before, during and after bloom, especially during wet periods. Use iprodione or thiophanate-methyl. |
|
| Dogwood anthracnose (fungus) |
 |
Dogwood anthracnose is a lethal disease of Pacific dog woods, flowering dogwoods and some varieties of Kousa dog woods. It is not established in Missouri to date, but be alert for symptoms: leaf spot, blotches and shoot dieback that are obvious in early spring to mid-summer, twig and branch die back occurring throughout the season, and proliferation of succulent shoots on the lower stem. |
Avoid bringing in planting stock from Eastern states. If you notice symptoms, please send samples to the Extension Plant Disease Clinic. |
|
| Leaf scorch (nonparasitic) |
 |
Margins of leaves turn brown. Most likely to occur when trees are planted in full sun, following transplant, or when nutrient deficient. Dogwoods may be nutrient deficient in soils with pH above 7. |
See leaf scorch in General Problems table. Avoid planting dogwoods on exposed sites. |
|
|
Powdery mildew (fungus) |
Leaves appear gray or white powdery on the surface. Young leaves may be distorted. Seriously affected leaves may brown and die. Powdery mildews have become serious in some areas of the South, but serious levels have not been seen in Missouri. |
Refer to the PDC Fact Sheet "Leaf Spot Diseases of Shade Trees and Ornamentals" for more information. If you think you have seriously damaging levels of this disease, please submit a sample to the Extension Plant Disease Clinic. Myclobutanil, thiophanate-methyl, thiophanate-methyl plus mancozeb, or triadimefon may be used if serious. |
|
|
Spot anthracnose (fungus) |
Common in wet seasons. Spots of various sizes, shapes and colors, often with dark-purple to brown borders. |
Refer to the PDC Fact Sheet "Leaf Spot Diseases of Shade Trees and Ornamentals" for more information. Apply fungicide once a month, starting in April when flower buds are in the cup stage and continuing until the flower buds for the following year are formed in late summer. Use copper fungicides (see label), quaternary ammonium compounds, mancozeb or thiophanate-methyl. |
|
| University Outreach and Extension does not endorse commercial products. Follow the label on all pesticides. |
