Disease Symptoms (Stem
bleeding of coconut palm):
- Soft, slowly
expanding decay of trunk tissues, darkening to black with age.
- 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.
- In advanced cases,
the interior of affected trunks are hollow due to decay of interior
- Basal stem invasion
may occur in wet areas, producing a black collar of diseased stem tissue
and the plant-soil interface.
- Roots may be
similarly blackened and decayed.
Pathogen: Chalara paradoxa (fungus)
species known to be susceptible to Chalara
Prevention and Treatment
- Avoid wounding palm
trunks at all stages of growth and during transport of palms, e.g., from
east Hawaii to West Hawaii.
- Avoid wounding stems
during landscape operations (tree trimming, weed whacking)
- Cut, remove and
destroy severely diseased plants, as they may serve as a source of disease
for neighboring plants if the environment is moist.
- In some cases, early
or localized infections can be excised through tree surgery, followed by
benomyl treatment (a fungicide), or other approved product(s).
- Early infection of
bud, leaf or stem tissues can be effectively treated by benomyl.
- Avoid direct
impaction of sprinkler irrigation water upon wounded palm stems.
- 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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