Tree stage:

3/27/2000 – green tip
4/7/2000 – half inch green
4/14/2000 – tight cluster
5/1/2000 – pink
5/4/2000 – early bloom
5/8/2000 – early petal fall
5/10/2000 – petal fall

*See apple scab lesions in commercial orchard – 5/8/2000
*See apple scab lesions in 3 commercial orchards – 5/11/2000

Apple scab infection periods:

4/8/2000 – 4/9/2000 : slight infection period, not significant unless had abundant scab in 1999.
4/15/2000 – 4/16/2000 : first significant scab infection period!!!
4/16/2000 – 4/19/2000 : off and on wet weather causing infection period(s)
4/21/2000 – 4/23/2000 : another significant scab infection period
last two wet periods have not caused apple scab infection periods (4/26-4/27 & 5/2)

5/5/2000 – 5/8/2000 : scattered showers causing some apple scab infection periods in many locations.
5/10/2000 : apple scab infection period
5/13/2000 : area wide apple scab infection period. Nearing the end of primary scab season. 90% of ascospores should be mature
5/18/2000 – 5/20/2000 : apple scab infection period; next week should end primary scab season. The real problem now is secondary scab spreading in orchards. I see apple scab lesions in many orchards!
5/22/2000 – I think primary apple scab season is over. But, our trouble with scab is not over. I see scab in more orchards than ever before. See lesions on fruit too.