Scouting for diseases: Botrytis blight
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EmailEditor’s note: This article is from the archives of the MSU Crop Advisory Team
Alerts. Check the label of any pesticide referenced to ensure your use is
included.
Editor’s note: This information is from the new field guide A Pocket Guide for IPM Scouting in Herbaceous Perennials. For ordering information, call 517-353-6740 or visit: http://www.ipm.msu.edu/pdf/pocketGuidesLandsc07.pdf
Pathogen. Botrytis cinerea. (view images)
Hosts. Very large host range, some of the most susceptible include Delphinium, Hosta, Iris, Lilium, Primula, Rudbeckia and Viola. Blossoms are especially susceptible.
Symptoms. Seedling blight,leaf spots and blight, distortion of young leaves, crown rot and blossom blight.
Signs. In high relative humidity, grayish, fuzzy mold on the surface of the affected tissue is visible with the naked eye.
Spread. Spores are produced in mass under humid conditions and
are readily released and moved by air currents. Additionally,
overwintering structures (sclerotia) are formed and can persist in soil
and plant debris. Sclerotia are found on the surface of heavily diseased
plant material.
Management. Sanitation and aeration procedures that reduce
humidity levels around plants and appropriate fungicide applications are
recommended for disease control. Botrytis cinerea can
sporulate on dead plant material; fallen leaves and petals should be
carefully removed from production areas. Trash cans used for dead plant
tissue should not be kept in production areas. Regular fungicide
applications will likely be necessary to reduce losses on especially
susceptible hosts grown in humid environments.
