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Plumeria Black Tip, What is it?
Is it a fungus?
What is the TRUE Cause?
With this short article we will give you some of the causes and the most effective ways to deal with
Plumeria Black Tip.
Sean Miller an entomologist has generated much interest in the black tip issue. He gave a very
interesting and informative presentation several years ago at the Southern California Plumeria Society
on his revealing findings. We have been collaborating with Sean as of spring 2003 on various issues with
plumeria black tip and stem
rot. We have made some very interesting scientific determinations based on his and our
studies and the results.
First and foremost their is no known fungus called "back tip".
Science does categorize or use the "naming" convention in this way.
books.google.com/books?isbn=1574444689...
"Plumeria Black Tip" as I have known it for over three decades is not a fungus or fungus related. If a fungus does attach
itself to the damaged tips it is after the necrosis starts. We have narrowed the issue
down over the last
five years to two totally different causes. And, we are not stating that there are not others (other than a fungus). Kimis Plumeria Nursery has sent affected tips for lab analysis (see picture ) which have ALL came back negative to any fungus on or within the tips.
So other explanations i.e. causes were determined by several side by side comparisons. One first must consider a plumeria trees dormancy issues in North America.
Plumeria go dormant in their native habitat for the purpose of surviving the dry season. In our latitude this happens to be winter. So the tree is
facing much unnatural stresses. Most issues with "black tip" are in fall, winter and spring however we have seen full blown "plumeria black
tip" in the middle of summer. This leads us to believe that black tip is caused by broad stresses to the plant.
The plant is genetically expecting hot dry conditions but cold and rain is
prevalent. This also is in part the reason for what is commonly called
"black tip". True tropical regions do not suffer cold conditions therefore
"plumeria black tip" as we know it doesn't exist. And as Sean Miller had discovered and
we have confirmed mites can be one of the causes of "black tip". Now that I carry a 10X loop in the field at all times I have become very aware of the
damage to plumeria by spider mites in any environment wet or dry. There is a misunderstanding of mite activity with many in the horticulture field.
Mites are not deterred by wet conditions alone. I have worked in high humidity commercial greenhouses in the past seeing serious mite issues.
In addition, we have had more mite issues in our own greenhouse this past several seasons than outside in the growing grounds. This theory of mites
don't like moisture or humidity needs some more thinking through.
It's a changing world out there and sad the Plumeria Societies don't
recognize these latest scientific findings. Sean Miller discusses treatment
for mites at his web site.
(..http://plumeriatc.org/) We mostly know how to treat fungal issues with
fungicides. This doesn't always rectify the problem, finding the source of
the stress is also part of the remedy. "Black tip" is much more complex then
a simple fungal issue this is why it can become very difficult to control.
How have we found success deterring the "black tip" issue? Prevention is the
number one way to reduce the incidence of "black tip". First begin with
analyzing your growing routines such as daily care inclusive of your
watering and fertilizing/feeding program. Horticulture science has proven
that plants under stress are more likely to succumb to insect and disease
issues. Always remember a strong healthy robust plumeria can resist issues
of disease and insect infection better than a weak and poorly maintained
plant. Consistent observation of your plants is essential to reduce chances
of disease or insect invasion. When one discovers a spider mite presence
immediately take action
 to control the outbreak.
(see our FAQ article Spider Mites A Simple Control)
True plant health eludes many. I say this because of all the hype of
"high middle number" fertilizers extolled by many pundits and
Plumeria Societies in their articles.
(see our FAQ "High Middle Number "P"
Fertilizers) These fertilizers are not even close to supplying plumeria the
amounts of Potassium (K) or other necessary nutrients for optimum plant
health. Stronger cell structure helps to prevent intrusion of disease and
deters leaf and stem piercing insects. Along with increased potassium (K) we
suggest the use of sea weed extract.
(..more info on
Sea Weed Extract)
Interesting notes on plant nutrients:
●Potassium-reaches a higher concentration in plants then any other
mineral element: activates over 60 enzymes
●Calcium-important for
the processes that take place in the cellular membrane and binds the cells
together A plant needs more calcium than all NPK combined
●Magnesium-a
key element in the chlorophyll molecule
●Iron-necessary in the
synthesis of chlorophyll
The lack of any of these elements means death.
You cannot say which is the most important
Applying alcohol or another
topical agent to a stem with "plumeria black tip" is not a bullet proof cure all.
I always cut off the black tip to prevent the rot to continuing down the stem
and also to help prevent an infection of a bacterial agent.
Dressing the cut with a sealing agent such as white latex caulking or latex
white paint will also help prevent bacteria intrusion. When I cut the stem
it will usually die back to the area of initiation and that’s it. That is
unless you have a secondary bacterial infection, which can continue until it
is eliminated by a systemic fungicide. A cutting does not have the resources
a growing/rooted plant does for curing itself. When this happens to a rooted
plant in fall the issue is more complicated as the plant is slowing down its
entire systems. Therefore its defense systems are not much protection. In
spring when the plant becomes active again I always make a fresh cut eliminating all the old dead tissue. The plant will respond to the new wound and begin making effort to grow new branches much faster.
We hope this material is useful for you now and in the future. If you have any questions I can be contacted by email; jack@kimisplumeria.com or telephone; (888)
819-4811.
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