hi,
x-posted -- what causes sap production (there are sap drops at the
leaves' bases (where the stem (?) attaches to the leaf))
this has been occurring since summer 2004 these are indoor plants
(tropical hibiscus) (no relation to h2o, food, light, humidity, soil, no
pests, etc...)
plants eventually lose all leaves and die
so would like to know what stimulates sap production to troubleshoot
tia

You probably have aphids or mealybugs, both are very common on tropical
hibiscus. What you are seeing is probably not sap, but insect poop.
On another note, sap production is a function of staying alive, the
only thing that would affect its production is temperature.

Toad

" wrote in
oups.com:

You probably have aphids or mealybugs, both are very common on
tropical hibiscus. What you are seeing is probably not sap, but
insect poop. On another note, sap production is a function of
staying alive, the only thing that would affect its production is
temperature.

Toad


Tanya might also be describing the result of extrafloral nectar that
some plants produce. It is generally used by the plant to feed ants
that would otherwise farm aphids on them. Extrafloral nectar is
generally produced in pit-like glands at the base of leaves, ends of
petioles, or other parts of the plant.

In addition to extrafloral nectar, some plants will produce fluid
under certain conditions. I refer to a process called 'guttation',
which usually occurs under very high humidity. This fluid is nearly
pure water.

Sean

hi and thanks for the reply!
[...below...]

" wrote:

You probably have aphids or mealybugs, both are very common on tropical
hibiscus.

no pests i have been over them with magnifying glasses (plus some have
those yellow insect *traps* - sticky) and there are no pests...

What you are seeing is probably not sap, but insect poop.

no it is very sticky and is *only* at the leaf base

On another note, sap production is a function of staying alive, the
only thing that would affect its production is temperature.

this began during the summer (2004) (i live in zone 5 -- these are
housePlants) and it continues now (and through the winter)
(the house temp fluctuates slightly summer - winter)
thanks

Toad

sincerely
Tanya

thank you very much for the response!
[...below...]

Sean Houtman wrote:

" wrote in
oups.com:

You probably have aphids or mealybugs, both are very common on
tropical hibiscus. What you are seeing is probably not sap, but
insect poop. On another note, sap production is a function of
staying alive, the only thing that would affect its production is
temperature.

Toad


Tanya might also be describing the result of extrafloral nectar that
some plants produce.

these are in the house (no ants) and i have thoroughly inspected them
for pests... (some had spider mites in the past (several years ago) but
i cannot see any now)
also i've tried safer's insecticidal soap (which made them worse)

It is generally used by the plant to feed ants
that would otherwise farm aphids on them. Extrafloral nectar is
generally produced in pit-like glands at the base of leaves, ends of
petioles, or other parts of the plant.

this is the location if the sap -- at the leaf bases (where it attaches
to the leaf stem(?) (i'm defining the leaf stem as the part that
attaches to the branch -- not certain about the term)
appears as a drop of fluid but is really sticky

this is in regards to tropical hibiscus (hibiscus rosa-sinensis)
housePlants most of which i rooted from cuttings; (since 2001)

In addition to extrafloral nectar, some plants will produce fluid
under certain conditions. I refer to a process called 'guttation',
which usually occurs under very high humidity. This fluid is nearly
pure water.

this problem started during the summer... (2004) with higher humidity
(however it has continued through the winter (zone 5))

Sean

i don't think that it is guttation (which afaik feels like water) --
would you know the name of the glands at the leaf base?
is there any other cause of gland activity apart from being used by
ants?
thanks very much again!
sincerely
Tanya
the end result of this is leaf loss and the plant dies...

Tanya wrote in
:

i don't think that it is guttation (which afaik feels like water)
-- would you know the name of the glands at the leaf base?
is there any other cause of gland activity apart from being used
by ants?
thanks very much again!
sincerely
Tanya
the end result of this is leaf loss and the plant dies...




The gland would be called an extrafloral nectary. Don't count on my
thoughts about the cause of the glands suddenly turning on. It is
possible that stress could cause a plant to produce more than
normal, and that stress could be leading to the loss of leaves, etc.

Sean

Sean Houtman wrote:

Tanya wrote in
:

i don't think that it is guttation (which afaik feels like water)
-- would you know the name of the glands at the leaf base?
is there any other cause of gland activity apart from being used
by ants?
thanks very much again!
sincerely
Tanya
the end result of this is leaf loss and the plant dies...




The gland would be called an extrafloral nectary. Don't count on my
thoughts about the cause of the glands suddenly turning on. It is
possible that stress could cause a plant to produce more than
normal, and that stress could be leading to the loss of leaves, etc.

Sean

thank you, Sean,
i'll look into the extrafloral nectary (as you mention, they may be
under some sort of stress -- all of them (regardless of where they are
etc.) have this feature...
thanks!
sincerely
Tanya