Help: RUST

[Mike Slater]

There is at least one alternative to destroying a plant affected with
Arisaema rust. (I believe I mentioned this several years ago either on this
list or on Aroid-L)

The rust is native to my area on local Arisaema triphyllums.  I planted an
A. sikokianum tuber and it did well for several years and even set seed. In
the third or fourth year the plant got a severe case of the rust. I
consulted with Judy Glattstein who is a friend of ours with much experience
growing Arisaemas and she told me (as I recall) that the rust is only in the
above ground portion of the plant and the tuber is not affected. She
recommended that I behead the plant (i.e. cut it off at ground level) and it
would likely survive and come back rust free the next year. This was in
June, early summer, long before the plant would normally go dormant.  I took
a deep breath and did as she suggested. It worked! The plant came up the
next year and bloomed (I didn't check it's sex) and lived on for another few
years and never had the rust again.  I believe the local outbreak of rust in
A. triphyllums had declined as I haven't had and cases in the garden on A.
triphyllum for over ten years either.

The only species I have had the rust on are A. triphyllum and A. sikokianum.

So, if you live in an area with the Arisaema rust present in local
populations, and thus spores in the air I would recommend you try the
beheading procedure.  However, if you live where the rust is unknown (no
local Arisaema triphyllum populations) and you have a case in your garden
you should probably destroy the infected plants immediately.


Mike Slater, Southeastern Pennsylvania, USA, z6