Gary W. Moorman, Professor of Plant Pathology
|ANTHRACNOSE||Circular to oval brown leaf spots have a yellow halo. Spots may become 2 inches in diameter and contain tiny black fungal fruiting structures.||Colletotrichum||Avoid overhead watering.|
|BACTERIAL LEAF SPOT||Small gray or dark green leaf spots enlarge and become irregular in shape, tan, dark brown or black.||Pseudomonas cichorii, Erwinia chrysanthemi, or Xanthomonas campestris dieffenbachiae||Purchase plants free of the disease. Remove infected leaves and water in a manner that keeps the surface of the leaves dry.|
|COPPER DEFICIENCY||New leaves are yellow,strap-shaped or distorted.||Lack of copper||Apply a micronutrient that contains copper. Damaged leaves will not recover. New foliage will form normally|
|MYROTHECIUM LEAF SPOT||Large gray-brown, oval leaf spots form at leaf tips or margins. Fungal structures form in concentric rings within the spots on the underside of the leaf.||Myrothecium roridum||Do not apply excessive amounts of nitrogen fertilizer.|
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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.
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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