Between Half Inch Green and Tight Cluster Infection period conditions rating is 5. 42 leaf wet hours, with 46 F degrees average temperature during wet hours. Infection period accompanied by daytime rain to release ascospores. Opportunity for sterol inhibitor or strobilurin fungicide 96-hour kickback ends Wednesday May 3 at 5 pm. First generation lesions arising from this infection period could show as early as Sunday, May 14.
Many orchards are in the same situation regarding scab.
The prolonged rains, and conditions being too windy to spray when it wasn't raining, have prevented protectant fungicide applications. Orchards that were free of scab last fall normally shouldn't have too much to worry about from infection periods prior to and shortly after Half-Inch Green. And in a normal year, starting a sterol inhibitor program before tight cluster is unnecessary. Many orchards have not had any fungicide protection at all so far this year. Though it is important to note that this kind of weather at Half-Inch Green is a completely different story than having it during the peak of scab maturity just prior to and following Bloom, which is what happened in 1998.