Re: arisaema rust/mayapple rust/

Knew the good folks on Trillium-L would know about the mayapple
rust...got two replies, both from very knowledgeable people.

Dr. Jim Waddick says this is fairly common on his local wild
populations of Podophyllum on an irregular- depends on the season-
basis with some plants getting it badly but it doesn't seem to harm
them in the long run.  He thinks it's just an opportunist fungi and
relatively harmless.

Jim McClements says he's noted it both last year and this year, more
on some special seedlings than adult plants and including some of the
Chinese species.  He checked with Barry Yinger (Asiatica Nursery) who
imports and sells a lot of the Chinese species. Barry says it's not
the same fungus as the Arisaema rust and doesn't seem as serious.
Barry uses Daconil to combat it, which he says works well for him.
Jim used the Daconil once and hasn't seen more infected plants since.

Personally, I'm relieved to find it's not as virulent as the Arisaema
rust, tho' I've not seen it on my populations of mayapple (knock on
wood).

Rust fungi (as well as hundreds of other disease fungi) are all
around all the time.  Most plants have a high tolerance for them and
survive with either disfigurement or some damage...rather like we
humans deal with the various bacteria and virus (viri?..what is
plural of virus?)  floating around us all the time.

I have never used Daconil, but search results appear to indicate it
is widely used for turf diseases. The Biocontrol In Greenhouses web
page

http://ipmwww.ncsu.edu/biocontrol/2a.htm/

seems to indicate it as one of the products which most predator
insects can tolerate.  Appears the primary ingredient is
chlorothalonil.  Extoxnet has a page on this with everything you'd
ever want to know about its toxicity to humans and other critters.
Appears it's fairly benign except for fish.

http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/chl
orothalonil-ext.html

So, seems as though, if you want to try using a control, Daconil - or
some formulation of it, appears that there are several - should be
worth trying.  As with any fungicide or pesticide, proper precautions
need to be taken and instructions on the package followed.

Marge Talt, zone 7 Maryland
mtalt@clark.net
Editor:  Gardening in Shade
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