North American Fruit Explorers mailing list at ibiblio

["Alan Haigh" <alandhaigh@gmail.com>]

So many things are involved with controlling scab including the mysterious, what the... kind of situations.  In my own orchard scab has never been much of a problem for reasons I fail to fathom.  I have a large crab apple that I refuse to spray that is covered with scab every season but none of my apples succumbs to the generous innoculum the crab provides.  I know that some of my varieties are susceptible and have required chemical control on other sites I manage.

 

Mancozeb is a late model fungicide mostly used around here as a co-mixer with Nova to delay resistance to the more affective Nova.  Resistance has become pretty wide spread anyway and commercial growers are switching to the strobes like Flint at least to alternate and maintain effectiveness of both S I's like Nova and strobes like flint.

 

In southeastern NY the most crucial sprays for controlling scab are usually at petal fall and about 10-14 days later for me.  I tend to tank mix Nova with Captan because I have read that Mancozeb is harder on beneficials and is more likely to lead to mite outbreaks.  Experience seems to bear this out.  I alternate with Flint alone.

 

I've never bothered to ask about the restrictions put on Mancozeb the last few years but you could probably ask the manufacturer if you don't have an expert to consult through your cooperative extension.