In years past I waited until May to spray immunox and triazicide on my apple, nectarine, pear, almond and cherries. Come June I was surprised to see that my trees were ravaged by plum curculio and bacterial leaf spot.
So this year I had enough of pests and diseases and made sure to start spraying at green tip phase in April. I am now rewarded with healthy looking trees and fruit that are not damaged by plum curculio. I have much respect for organic pomologists as maintaining an orchard without artifical pesticides and pesticides is very hard. Next step is to hand thin fruit in the next few weeks after June drop starts.