Disease Symptoms (Stem bleeding of coconut palm):


  1. Soft, slowly expanding decay of trunk tissues, darkening to black with age. 
  2. As decay progresses, a darkly pigmented liquid bleeds down the trunk from the point of invasion (usually a stem wound, e.g., Figure 1), covering the stem surface with a superficial black layer of stem fluids.  The sap flow may extend several feet down the trunk, blackening the trunk as it dries.
  3. In advanced cases, the interior of affected trunks are hollow due to decay of interior tissues.
  4. Basal stem invasion may occur in wet areas, producing a black collar of diseased stem tissue and the plant-soil interface.
  5. Roots may be similarly blackened and decayed.


Pathogen: Chalara paradoxa (fungus)


Palm species known to be susceptible to Chalara paradoxa:


Areca catechu

Brahea edulis

Caryota spp.

Cocos nucifera

Elaeis guineensis

Phoenix africanus

Phoenix canariensis

Phoenix dactylifera

Raphis sp.

Roystonea elata

Sabal palmetto

Sygarus romanzoffinia

Washingtonia filifera


Prevention and Treatment


  1. Avoid wounding palm trunks at all stages of growth and during transport of palms, e.g., from east Hawaii to West Hawaii.
  2. Avoid wounding stems during landscape operations (tree trimming, weed whacking)
  3. Cut, remove and destroy severely diseased plants, as they may serve as a source of disease for neighboring plants if the environment is moist.
  4. In some cases, early or localized infections can be excised through tree surgery, followed by benomyl treatment (a fungicide), or other approved product(s).
  5. Early infection of bud, leaf or stem tissues can be effectively treated by benomyl.
  6. Avoid direct impaction of sprinkler irrigation water upon wounded palm stems.
  7. Inspect all new palms for symptoms and do not even plant them if they are diseased.

Note: References to products in this publication are for your convenience and are not an endorsement or criticism of one product over similar products.  Follow the label directions exactly to protect the environment and people from chemical exposure.

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