Penelope said:

However, why do you think the ants are causing the problem with your
gardenia? Unless they're herding aphids, I don't see how the ants
would hurt the plant.

AAh, well, ants setting up house in a potted plant *can* cause problems,
and not just by farming aphids, as I've found out this year.

Two identical (well, mirror-imaged) containers of flowers, planted at
the same time, same treatment. The one with the ants suffered (wilting,
yellowing, root damage). The one with no ants is fine.

I suspect that the original poster's problem likely did involve aphids, as
he mentioned sooty black mold on the leaves. Driving off the ants would
be useful, as they protect and distribute ('herd') aphids.

Spinosad is derived from a bacteria and is available in products certified for
organic produce.

It is recommended for drenching for fire ant control and would probably
work for other ants as well (though it wouldn't be useful against aphids
or other sucking insects).

Green light makes a spray concentrate with Spinosad, as does Monterey
Garden. (Do a Google product search for Spinosad and you will have
your choice of online vendors.)

Locally, I'm able to buy a pre-mixed Spinosad product by Bonide named
(sort of annoyingly) 'Captain Jacks Dead Bug Brew' which I've been using
on my cabbages and kholrabi this year with good results (no sign of
cabbage worms -- better results than Bt).


--
Pat in Plymouth MI

"So, it was all a dream."
"No dear, this is the dream, you're still in the cell."

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