North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

Because I manage so many orchards at so many different sites in the
southeastern NY area I think I've got a pretty good idea about CAR
control.  First thing to know is that it is a huge problem for organic
growers and there is no practical solution for them in high pressure areas,
short of limiting your selection to highly resistant varieties.  However,
myclobutanil, found in the home formulation called "Immunox" can give
control with as little as two applications starting at petal fall and
following up10 to 14 days later.  Happily this will also probably control
scab and if you include something like Triazicde (Ortho Once and Done, a
pyrethroid)  in the mix you will have a good chance of controlling
everything that stands between you and a successful harvest (in the
northeast).

I manage one orchard where one tree continued to get a fair amount of CAR
even with the 2 applications.  It was not in the orchard proper but behind
the house (mansion, actually) and in the adjoining woods I found a large
cedar tree not a 100 ft away.  Just anecdotal, but I'm convinced that its
local proximity increased the pressure, although it was an older tree of a
different variety than trees in the orchard.  There were plenty of
susceptible varieties in the orchard though, such as RI Greening and Yellow
Delicious (the old strain that actually tastes pretty good).

Pest control is an extremely local affected issue so even though my
experience is in 3 states and 3 different zones it still doesn't cover
enough territory to be at all definitive.

Here's some varieties Tom Burford considers resistant.  Arkansas Black,
Ashmead's Kernel (what an apple!), Empire, Enterprise, Freedom, Fuji,
Golden Russet, Granny Smith, Grimes Golden, Hawaii, Jersey Mac, King David,
Liberty, Limbertwig, Macintosh, Melrose, Ralls, Roxbury Russet, Spartan,
old strain Stayman, St. Edmonds Pippin, Virginia Beauty, William's Pride,
old strain Winesap and Yates.

Some very good apples in that selection, I'd say.