on dealing with Wilt and Dieback disease in Hibiscus
Author's note: Below is a description on Wilt and Dieback disease in Hibiscus
plants and some suggestions on dealing with it. Mr. Charles Black
of Hidden Valley Hibiscus provides this information. He has
graciously allowed us to use this information on our web site, for
which I am grateful.
Wilt and Dieback
can be prevented in many cases but only if one is willing to embrace
an overall control strategy. Here are a few techniques taken
from a number of professional books I have plus some experience dealing
with these problems at Hidden Valley Hibiscus.
wilt: The cause
disease is no different from wilts that affect many ornamental plants.
It is caused by fungus with such intimidating names as Fusarium oxysporum
and Vertocoium. This disease is often referred to as "root rot" but
that is a misunderstanding of the problem. What is actually
happening is that pathogenic fungi are rapidly reproducing in the
soil mix of the pot and entering the plant through roots. The
roots of such plants do not show any "rot" except possibly
tnicillium the late stages of the disease if the plant survives that
Once inside the
plant, the fungi disrupt the capillary system of the plants, preventing
water and nutrients from circulating normally. That is when
yellow and or droopy leaves appear over the entire plant or over one
side of the plant. Do not confuse this with a few wilted leaves
at the top of a stem (more on that later). Also always check
to be sure the plant has sufficient water as dryness is the most common
cause of wilting. If the plant remains wilted although there
is ample water, read on……
What can be done?
before wilt occurs:
the wilt appears:
- Keep your
pots clean. Remove dead leaves and flowers from both the plat
and the pot.
- Control insects
as tey can spread disease and make wounds in the plant that pathogens
- When transplanting
try not to wound the plant, as such wounds are entry points for
- Do not over
fertilize when the soil mix is dry as this can burn the roots
and make the plant more vulnerable to attack.
- Adjust watering
to match the season and the weather. In the summer they
need lots water often daily, but in cooler times reduce the frequency
of watering so as not to create conditions that favor fungi growth.
- Apply worm
castings to the surface of the potting mix, working it into the
mix as best you can. Start with a layer that is ½"
to 1" of castings on the surface of the potting mix. This
has reduced my problems with wilt of young transplants to almost
zero the last several years.
- Apply Rootshield/Plantshield
beneficial fungi according to label directions. This material
is similar to the worm castings but perhaps mote potent and targeted
to diseases problems.
but recommended for those with continuing disease problems. In
fall and again in spring drench your pots with fungicides.
Phyton (copper based), any product containing thiophanate methyl
such as Cleary's 3336. Domain or Fungo or other fungicide recommended
by your local Ag extension office (I like Medallion personally)
will help to remove or suppress fungi. Subdue Maxx is not
recommended as it is specific for other types of fungi that do
not usually cause the wilt disease nor the dieback disease in
hibiscus (advise you might see elsewhere notwithstanding).
try an emergency save by mixing 1 pint of house bleach with 2
quarts of warm water and pouring the solution into the pot with
the wilted plant, saturating all of the potting mix. This will
kill off the fungi in the mix but will not affect the fungi already
in the plant. Sometimes the plant recovers after this, sometimes
not. If the plant is still alive a week later try adding
Plantshield/Roorshield to the mix so that these beneficial and
protective fungi will colonize the roots again. A transplant
shock treatment containing Vit B is also good, Superthrive being
one such product.
to bleach, use the fungicides above as a drench in the potting
removing the wilted plant from the pot, removing as much soil
as possible from the roots and then washing the toots with clean
water can achieve a rescue. Afterwards repot in fresh clean soil
mix in moist, but is not sopping wet potting mix.
- While the
plant is recovering keep it in the shade and do not over water
it. New leaves will appear after some days or even weeks
if the plant is recovering. If no leaves appear, try scratching
the bark on the main stem it see if there is green underneath.
If not then the plant has died and should be disposed of the property
place in plastic a bag and place in the trashcan is one method.
- Wilt is a
serious plant disease. Prevention is better than a cure as many
plants will perish once they have it, no mater what type of "cure"
This disease happens
whenever fungi or bacteria enter a stem through a wound and causes
a rot to begin at the point of entry.
The most common
type occurs when a flower does not fall from the plant but remains
attached to the peduncle (stem that attaches the flower to the plant).
Both the old flower and peduncle are eventually invaded by fungi and
or bacteria, and if left on the plant the infection spreads from peduncle
and then into the plant where the peduncle attaches to the plant.
most common form happens when the flower falls off the peduncle
but is caught in the stems and foliage of the plant and is held against
on to the main stems. Here it will be attached be fungi such as Botrytis
and as it molds and rots it passes this infection on to the stem is
clouds, and poor air circulation encourage dieback disease, which
is why it is seen most often during periods when weather creates these
of dieback can occur from internal infections of the plant similar
to those that cause the Wilt Disease. In the case of dieback
the fungi or bacteria (Erwinia sp mostly) do not block the circulation
of nutrients enough to cause wilt but instead accumulate at the very
tips of the stems where they will sometimes appear to explode of the
top of the branch.
before the dieback occurs:
the dieback appears:
- Remove all
spent blooms from the pants.
- Remove the
peduncle that was holding the flower. Do this carefully so as
not to create a wound in the side of the stem.
- Provide good
air circulation with fans or plenty of vents if indoors.
- Wet conditions
will contribute to the problem. If there is anyway to prevent
plants from being wet, particularly at night, do this.
- Follow the
same smart growing practices as outlined for wilt disease, such
as cleanliness, insect control etc.
- Promote a
healthy soil using worm castings and or beneficial fungi.
- Dieback is
less often fatal than Wilt Disease if one acts quickly to control
- The best
way to deal with dieback is to cut away the infected part of the
stem(s) from the plant. Find the source of the infection, which
will appear as a dark of discolored area on the stem. Often there
is wilting of leaves immediately above the infected area. Go down
the stem one or two nodes and then cut the stem ¼ inch
above the node, removing the infected area. Dispose of the
bad wood in the trash, not on the ground.
- Next, look
at the inner core of wood it has been cut. It should appear
clean and white. If there is dark streaking visible it is best
to go a few more inches down the stem and cut again. Keep doing
this until clean weed is found. It does not hurt to apply grafting
wax to such cuts as this will help prevent re-infection thru the
cut. Alternatively, painting the wound with Phyton (Copper biocide)
diluted to label specified strength is a good idea, too.
- Most Hibiscus
will recover from Dieback if the infection is removed from the
plant, if not removed it can spread to the entire plant and kill
it. But often-older plants will stop the infection before that
point. Still, it is best to remove the infected area, which also
serves as a pruning for the plant, something the plant needs from
time to time anyway.
in Hibiscus have found a half dozen or so viruses. However, most commercial
labs do not even have tests to detect them. There role in Hibiscus
disease is poorly researched with little information available, but
common diseases must Hibiscus growers will see have been diagnosed
by labs as caused by fungus and sometimes by (Erwinia ct.). The symptoms
are classic for these type of diseases and the prevention and cure
of them is also well established as they are basically the same in
all ornamental plants.
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