For all us permies, we're used to looking at what we can get from plants, even noxious ones. (scotch broom=nitrogen fixation, morning glory=LSD, etc!)
I'm just reading 'The Apple Grower' by Michael Phillips. On p. 243 he says that a water extract of Hedera Helix has been used to control apple scab.
Score! Scab afflicts many apples here in Pierce County, and English Ivy is running rampant in nearby forests. Maybe we could not only take out the ivy, but someone could make money turning the ivy into anti-scab elixir!!
okay, in the few hours since the post i've found this, http://www.pierce.ctc.edu/biology/arboretum/ivy.htm, which just mentions the swiss study and talks about ivy being a 'succesful ground cover' (duh!) And a hair dye. but no more info than 'water extracted.'
okay, and then a lot of websites with no info on it. Where's a Swiss person when you need one? Who can read that study and pass it along to us?
Apple scab season will soon be upon this. Everyone experiment and keep track of what happens! Even a study in Switzerland won't be able to tell us how our particular hedera helix and our climate and our scab all interact. We'll have to figure it out anyway.
You guys probably already know this, but you can buy Ivy Extract at most nutritional supplements stores. Apparently a bunch of studies have been done that show that it's a fantastic cough expectorant, better at relieving bronchitis symptoms than many prescription medications. I imagine you'd want to dilute this solution to use it on your scab, but might be easier for the purposes of experimenting than making it yourself:
Brave New Leaf - Everyman Environmentalism http://www.bravenewleaf.com