May 31, 2015

by Terence Bradshaw

After last night’s rains, I would say that every orchard in the region experienced an infection period last night that will likely continue through Tuesday. Because it has been so dry this spring, few opportunities have been available to release of apple scab ascospores, so a large amount of this season’s inoculum is releasing during this event. Orchards protected with a protectant fungicide applied Thursday or Friday may be fine through this event without recovering, depending on the amount of rain that falls. It would still not be a bad idea (and is a very good idea for anyone going into this with questionable coverage) to apply a good kick-back fungicide (strobilurins, DMIs, or SDHIs) when things dry out and you can next get back in.