|Cold Injury||Reddish dead areas form on leaves within five days of exposure.||Temperatures below 40° F.||Do not place plants near air conditioners. Maintain temperatures above 45° F.|
|Fluoride Injury||Chamaedorea palms' leaf tips turn dark brown and die. On areca palms, small dead spots form in chains between leaf veins.||Excessive fluoride in soil.||Maintain soil pH between 6 and 6.5. Avoid using perlite and super-phosphate. Do not irrigate with water containing 1 ppm fluoride.|
|Helminthosporium Leaf spot||Reddish-brown to black oval spots less than 1/4 inch in diameter merge to become irregular in shape.||Drechslera setariae, Exerohilum rostratum, Phaeotrichoconis crotalariae||Avoid overhead watering. Apply a fungicide to protect plants.|
|Iron or Copper Toxicity||Oval dead leaf spots have yellow halos and may be confused with Helminthosporium leaf spot.||Excessive iron fertilization or copper fungicide use||Do not use copper fungicides. Do not use iron sequestrene under low light, high nutrient conditions.|
|Leaf Burn||Tips of lower leaves turn brown and die.||Excessive fertilization||Maintain moderate levels of fertilizer.|
For more detailed information, see Compendium of Ornamental Palm Diseases and Disorders. 2004. Ed. by M. L. Elliott, T. K. Broschat, J. Y. Uchida, and G. W. Simone. APS Press. 69 pp. with many color photos (1-800-328-7560). A CD of palm diseases and disorders can also be purchased at that site alone or in combination with the compedium.
Prepared by Gary W. Moorman, Professor of Plant Pathology
This publication is available in alternative media on request.