Fire Blight. If any of your trees still have open flowers, there is the potential for fire blight infections. Very young trees are especially vulnerable now, because these trees may still be in bloom. If you or your neighbors had fire blight last year, consider applying a strep spray now. Here is what Jon Clements from UMASS said:
“ Those of you who planted trees this year may have some in bloom. The weather conditions this afternoon (Monday) are very favorable for blossom infection if you have open bloom and we get any rain. You do not want to get fire blight in young trees! If you have a young orchard in bloom I suggest you apply streptomycin (Agrimycin 17 WP, 1.5 lb/acre) to the trees before it rains or just after. Pre-rain application is best, but if you come back within 12 hours of the rain (sooner the better) you will be effective with that application too. This is a very serious situation in young trees and not to be taken lightly. Again, it applies only to trees with open bloom, and particularly those on susceptible rootstocks like M.9.”

Scab.We are probably at the end of primary apple scab season. I think that today’s rain could release the last of overwintering ascospores. It is still two weeks before all the lesions from primary scab infection periods will be visible. If you feel confident that your trees have been well protected, you can switch to a longer interval between fungicide applications. IF you do not feel confident, continue with the tight schedule for another two weeks so there is fungicide present in case scab lesions appear.

Plum curculio. Today, Tuesday, is perfect plum curculio weather. It is warm and humid, exactly what makes plum curculio active. Hopefully all your trees are protected with an insecticide today. Using Orchard Radar as a guide, the final plum curculio insecticide needs to be applied June 1 or later.

I do see the winding scars of European apple sawfly, but the sawfly are not boring into a second fruit yet. Last year I started seeing sawflies entering their second fruit on June 5