Arisaema rust

[Jean Halverson]

Thanks, Jim, for posting the previous thread on this subject.  I have a small, isolated
wooded area that was previously fenced in and pastured and had virtually no native
plants left. This rust showed up about 3 years ago, possibly brought in with triphyllum
specimens planted here.  I haven't checked the nearest native population (which is also
on my land) but if it is not infected, I have a couple of questions.

1)Does any one know what the alternate host is?  Are alternate rust hosts usually
trees/shrubs and will they have the same orange spots?  I haven't noticed any other
plant material with similar symptoms but haven't specifically looked either. How close
does the alternate host have to be?

2)So far, my treatment has been sporadically pulling out infested plants, obviously not
an effective solution.  One of the postings said the roots wouldn't be infected.  Does
that apply to the corms as well or should they be destroyed?  Since I don't have any
non-native variations of triphyllum planted there, I can survive the thought of doing
that.

3)How far do such air born organisms travel?  If the native population is infected, is
there any hope of having a bed of triphyllum 500 feet away uninfected?

It's easy in the dead of winter to plan what I'll do next spring but I'll try to
experiment with some infected plants to see if the tuber remains uninfected unless
someone already knows the answer!
Jean Halverson
Wisconsin