On 26 July we visited a classic training system orchard in south part of Winchester, VA, with trees of apple cv. 'Ginger Gold' and detected symptoms of Apple Blotch Disease (ABD), also known as Marssonina Leaf Blotch (MLB). The symptoms were found on the lower scaffolds in the canopy and are visible in Figure 1 . This disease primarily expresses on apple leaves and is caused by a pathogenic fungus Diplocarpon coronariae . Even though we recently experienced dry weather periods in the Shenandoah Valley, e xcessive rains we received in May and June 2021 favored the development of ABD. Leaf symptoms express as grey to brown large round spots (blotches) that can merge. This leads to leaf yellowing. Figure 1. Apple Blotch Disease (aka Marssonina Leaf Blotch) on apple cultivar 'Ginger Gold' in Winchester, VA. If effective fungicides are not applied timely, continued infections by D. coronariae can occur during s...
Disease management information for Virginia tree fruit industry during the growing season by Srdjan Acimovic, Virginia Tech's Agricultural Research and Extension Center in Winchester, Virginia.