Ornamental Pathology Facts

Gary Moorman
Professor of Plant Pathology

Palm Diseases

Disease	Symptoms	Pathogen/Cause	Management
Cold Injury	Reddish dead areas form on leaves within 5 days of exposure.	Temps below 40 degrees F.	Do not place plants near air conditioners. Maintain temperatures above 45 degrees 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 superphosphate. 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 chlorothalonil, iprodione, or mancozeb to protect healthy leaves.
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.

Fungicides mentioned above:

COMMON NAME TRADE NAME

cholrothalonil Daconil 2787, Exotherm Termil

iprodione Chipco 26019

mancozeb Dithane, Protect T/O

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Last modified Wednesday, August 2, 2006