Astilbe Diseases
| Disease | Symptoms | Pathogen/Cause | Management |
|---|---|---|---|
| Flower failure | Plants do not flower but otherwise appear healthy. | Not a disease | Divide and replant to alleviate overcrowding. |
| Foliar nematode | Brown areas on the leaf are restricted in shape by leaf veins. These angular spots are usually seen on the lower leaves. | Aphelenchoides | Remove the leaves showing symptoms. Thin dense clumps to improve air circulation and irrigate in a manner that keeps water off the foliage. |
| Leaf scorch | Margins of leaves turn red to reddish-brown. | High temperatures, dry soil, windy conditions. | Move the plants to a shady, moist location. Note that leafhopper feeding can also cause leaf tips to redden and brown. |
| Leaf spot | Well defined dead spots form on leaves. Under ideal conditions of wet weather, spots merge and result in large dead areas on the leaf. | Cercospora | When watering plants, do so in a manner that keeps water off the foliage. See the NOTE below. |
| Powdery mildew | White fungal growth develops on the upper surface of leaves. | Erysiphe polygoni | See the NOTE below. |
| Root knot nematode | Galls form on roots and plants may be stunted. | Meloidogyne | Remove infected plants. Cultivate the area to remove all plants and leave the soil bare for a growing season before replanting. |
| Virus | Plants are yellowed but roots appear healthy. | Tobacco ringspot virus | Remove infected plants. |
| Wilt | Plants are stunted or wilted and have brown sunken dead areas on the stem near the soil line. | Rhizoctonia or Fusarium | Remove affected plants. |
NOTE: Although there are no fungicides specifically labeled for Astilbe, there are some for ‘ornamental use.’ These can be applied but the user assumes all liability for possible plant damage. If the label states that the fungicide is effective for a particular plant disease, apply the chemical to a few plants and wait 24-48 hrs to see if damage occurs. If none occurs, it may be safe to use that chemical more extensively on that variety and test it on other varieties prior to extensive use.
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DISCLAIMER
Notice: The user of this information assumes all risks for personal injury or property damage.
Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams or ponds.
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