I live in Virginia and recently purchased 10 apple trees of varying types including Golden Delicious, Arkansa Black, Pink Lady, Granny Smith. I planted in late February and the trees have looked great up unit the last 1.5 weeks. Now the leaves are developing yellow spots with burned tips. This is happening on all trees. We used the fruit tree spikes in March to boost them and we have experienced a fairly wet spring.
Does anyone have thoughts on possible causes?
Well those leaves pictured have a lot of Cedar Apple Rust, brown tip could just be environmental stress.
Thats what I thought initially as well. Everything I have read online suggested Cedar Rust would have red/brown rings around the outside of the spots.
If it is Cedar Rust, what is the best treatment and should we do it now or after the blooming season?
I agree that is probably CAR, but to be sure look at the bottom of the leaves, there should be some hairy growths. If that is CAR it is a pretty bad case of it!
It is a once-a-year thing, you need to treat it right after petal fall (that timing anyway) with myclobutanil aka Immunox. At this point there is no reason to spray and the new leaves coming out later in the summer will not be infected.