VIRGINIA TREE FRUIT DISEASE UPDATES

  I.  APPLE SCAB If apple scab was not controlled timely last year and primary and secondary infections on leaves were visible at any time during the season, you should aim to reduce overwintering scab inoculum residing in leaf litter on the orchard floor. Especially conducive for apple scab fungus overwintering are numerous late summer and fall infections visible as small lesions on the underside of the leaves (Figure 1). Figure 1. Late summer and fall scab infections on the underside of apple leaves (Photo by S. G. Acimovic, 2009). These fall scab lesions are the most productive places where apple scab fungus will grow into the tissue of leaves after they reach the orchard floor and form initials of pear-like fruiting bodies of the fungus called pseudothecia (Figure 2). The pseudothecia facilitate release of apple scab ascospores in the spring with each wetting event.  Figure 2. Round-like pseudothecium of apple scab fungus harbored in the dead leaf tissue visible under the mic

  The preliminary efficacy trial results conducted at AREC in 2021 can be downloaded via this link: Preliminary Report on Efficacy of Gatten and Parade Fungicides in Control of Apple Powdery Mildew at AREC in Winchester VA Figure 1. RIMpro apple powdery mildew output for April 2021 in Winchester, VA.