As a grower I observe my plants. From observation I try
to form a picture of what nature is doing. I cannot say what is
going on beyond these observations. But I will not offer
theories of fungus, insects, etc. because I have no proof or
evidence of those.
These examples of tip pimples, bruises and black spots are not
rot. Rot is a malignant disease that will spread like
gangrene to kill an entire cutting.
is not about this! (left)
That is rot; everything turns to brown slime. It
spreads from one end to the other of an infected
cutting by overwhelming the plants immune system.
can travel up from rotting roots and spread
through the core of cuttings. It is common during
the rainy season or in winter when the plants are dormant.
longer take cuttings during the winter or during
cold, wet weather because of the problems with rot.
Rot has one cure; amputation. You have to cut
well ahead of its spread to save parts of a plant
not yet destroyed. If roots or lower portions begin
to rot you should cut off the upper sections
to callus and save for replanting.
A) SPONTANEOUS TIP PIMPLES ON NEW GROWTH TIPS
1) Tip pimples will appear on both cut and uncut tips. They will
appear on rooted, healthy plants.
alone; no fungicide, no insecticides!
those who don't want to read all this
worry, don't obsess
• Do nothing and it will run its
course and go away
2) Tip pimples seem to appear when there is very rapid growth,
in summer, from a heat wave. After sudden jumps from 90 F to 107
F many plants developed rashes of tip pimples. Yes, even on ones
cut and being allowed to callus.
3) Tip pimples can fade away.
4) Tip pimples can leave behind a v-shaped scar similar to
"stretch marks" in human skin.
5) They appear on cut tips if the spines are allowed to scratch
adjacent tips--this occurs anywhere on the column scratched by
another--something like a rash, or small local scratch.
6) Scratches heal to form tan colored scars, tip pimples can
fade away or leave behind the v-shaped scar marking that year's
growth spurt heat wave.
B) INJURY MARKS ON NEW OR OLD SECTIONS
1) Mechanical injury such as bruising or punctures can result in
a black area. This is similar to a bruise on a person.
as this example will normally not spread.
This is NOT rot. Do not use any fungicide, etc. In
this particular example the little bud should be
snapped off and the log (column section) rooted. In
the future plenty of new buds will form.
2) Punctures or bruises form more easily on young, new growth
tips. But old, thick columns can be bruised--but it takes more
mechanical force to injure one.
3) The aftermath of an injury bruise is a scar.
C) BLACK PUSTULES APPEAR INEXPLICABLY ON PLANTS
(left) This may
be a fungal disease such as "black spot".
never used a fungicide; it always stays localized
and runs its course. Why? Because a healthy plant
has an immune system and can heal itself.
How this occurs on one out of 50 similar plants
under similar conditions is inexplicable. The black
spots heal into tan colored scars.
(above) one of my plants.
(below) photo emailed from unknown person.
1) A rooted plant one day shows a black spot. This can grow,
swell, spread, and even weep liquid.
2) Pustules can appear on one plant but not affect ones growing
nearby under the same conditions.
3) Pustules can occur during the dormant period when the plant
is not being watered, or in the spring or autumn. They seem less
common during the growing season.
4) Pustules can flow downward on a column.
5) Pustules can be cut open and drained, flushed with alcohol.
6) Pustules can be left untreated.
7) Every pustules on my plants has "run its
course" as a localized infection. The aftermath is a tan scar.
|Close up of the plant at left. I do not
know what the person did to make this plant
so unhealthy, but the twist tie holding it
up is a big hint that this was a sick plant.