Not sure if anyone can use this info, but I’ve made some observations on my apples about CAR resistance this year. Seems to be bad year for it, even my serviceberry was infected.
I have a handful of grafts on Liberty and Enterprise trees: Sweet 16, Goldrush, Pristine, Victoria Limbertwig, and Black Limbertwig. Sweet 16 is the only graft showing the telltale leaf spots of CAR, which matches what I’ve read since it’s more scab resistant than anything else.
I didn’t apply any fungicides.
I have CAR on three apple trees this year. A first! It is on Pristine, Enterprise and Jonagold. I started spraying my Immunox late and am about to spray Captan. This is the first year for it in my orchard. After spraying Immunox, the bright yellow dots have stopped forming.
I had a light year here for CAR. The Immunox program (Ty, H’man) on the very susceptible Urban Apples kept them squeaky clean. I was just admiring the perfection of their leaves last evening. My N. Spy - which usually has a good case of CAR, and its too damn big to spray as is (its getting reduced in March) - has a milder case than usual.
Galls seen on cedars were from April to early June, in waves.
Knock on wood I have zero CAR anywhere this year. I still really think the myclobutanil combined with sulfur does better than either one alone. A two pronged attack maybe?
Perhaps the sulfur provides some medium by which more myclo remains on the leaf surface. Sulfur does however have some efficacy in combating it.