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sticky substance on leaves

DLO News J.Harbinson at ATO.DLO.NL
Thu Sep 23 04:23:00 EST 1999

Many plants have extra-floral nectaries (ie necataries not in the flowers)
that will exude a sugar-containing (probably sucrose) syrup that can be very
messy. In my experience this tends to be a problem with older leaves. I also
think this process should probably rule out some plants for use as
house-plants, but no-one else seems to think so. Insect pests can also
produce a sugar-rich exudate (the story is that the the phloem sap, which
they suck from the plant, is low in protein and high in carbohydrate, so the
insects dump the excess carbohydrate on your carpet - thoughtless of
them....). Lastly, and this is just based on crude observation, I have a
suspicion that insect pest attack may stimulate the activity of extra-floral
nectaries in some plants; in some of my plants (eg Citrus, Stephanotis,
Zamia?) attacked by either scale or mealy bug I have seen substantial
production of sugary sap on parts of leaves with no insects. The
solutions? - put the plants in the shower, and wash them with warm water
twice, the first time to wet the leaves, and the second some time later to
wash off the dried sugar syrup which will have been dissolved or softened by
the water, or, if is due to an insect pest, kill the wee buggers.
all the best,
Jeremy Harbinson

Forng wrote in message <37e4115f.25543739 at news>...
>Hi there,
>I have a green plant (don't ask me what type) indoors, that has a
>sticky substance on the leaves, that seems to fall to the floor.  The
>strange thing is I can see no drippings of any sort, nor are any bugs
>Can someone help me?  Point me towards a good page that might help me?

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