| Table 4a: Scouting for Root and Stem Rots. | excerpt from: New England Integrated Pest Management Scouting Guide for Poinsettias: A Manual for Growers and Scouts |
| Disease | Scouting |
| Rhizoctonia root and stem rot | On cuttings: Look for a dry, brown discoloration at the cutting base that may develop before or after rooting. On mature plants: Look for dry, brown stem canker at the soil line. Lower leaves may yellow and drop, roots rot and entire plants may die. |
| Table 4b: Scouting for Botrytis Blight | |
| Production Phase | Scouting |
| On Cuttings | Look for blighted leaves or decayed cuttings. |
| On Mature Plants | |
| On leaves: | Look for brown, blighted lesions. |
| On stems: | Look for tan, sunken cankers. These cankers may develop on older stems, at the base of the petioles of blighted leaves. |
| On bracts: | Look for necrotic tissue at the edge of the bracts that gets darker as lesions expand. Do not confuse Botrytis blight with injury from pesticide sprays, overhead fertilization, or bract necrosis. A diagnostic symptom is the presence of a whitish-gray or light brown cobwebby mold that develops under conditions of high relative humidity. |
| Table 4c: Scouting for Powdery Mildew | |
| Production Phase | Scouting |
| On Incoming Cuttings | Look on the underside of leaves for the small, circular colonies while inspecting cuttings for immature whiteflies. Active colonies are white and "fluffy." |
| During Crop Production | Look on the upper and lower leaf surface of the lowest leaves for white, talcum-like patches (1/2"). With a 10x hand lens, look for the fungal mycelium radiating out from the center. Do not confuse with white spray residues that tend to be more variable in shape. |
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