In article ,
"Geoff" writes:
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| You may remember that a short time ago I recommended using large modified
| plant pots (8-9 inch diameter), inverted over runner bean plants to enable
| watering and feeding liberally but not wastefully. Well, it has other
| advantages apart from watering and slug/snail barrier for I've noticed no
| ants which I reckon carry aphids from one part of a plant to another. The
| beans still have blackfly but I keep them under control with regular
| spraying with a soft soap/rainwater solution. Soft soap is made with
| caustic potash instead of the caustic soda used in the manufacture of
| household soap which is not anywhere near so effective against aphids.

I have very little trouble with aphids on my runner beans - perhaps my
ants eat them all :-)

More seriously, I doubt that your pots have anything to do with the lack
of ants, just as much as I doubt that the ants have a significant effect
on the aphids. The long, miserable winter is more likely to be the cause
of a lack of ants.

Why do you invert the pots, incidentally, rather than just using them
the normal way up with the bottoms cut out (which I assume is your main
modification)?

| However, not all in my bean patch is rosy! Some of the plants' leaves are
| "bobbly" and become withered and dried at the edges. The affected leaves
| are very frangible even though still green. Some - about half - of the
| affected leaves had been attacked by aphids but I do not think they were the
| cause.

My guess would be a virus - probably aphid transmitted. And there is a
VERY high probability that the aphids that brought the virus were flying,
mature females. My observations on broad beans indicate that such a
female will lay eggs on several plants in a single trip.

If it is a virus, there is damn all you can do, except destroy infected
plants to stop it being spread by aphids (which can crawl, and be washed
by rain, from plant to plant, whether or not ants transfer them). If most
of your plants are affected, get what crop you can and hope for better
luck next year. Such viruses do not survive composting, incidentally.

If the new leaves on an affected plant don't show that trouble as they
enlarge, it isn't a virus.


Regards,
Nick Maclaren.