First Rust and Secondary Powdery Mildew Symptoms Visible on Apple Leaves in Winchester VA

All the major apple fungal diseases in the Shenandoah Valley are visible, except apple scab. This morning I found first fresh rust (Fig. 1, 2) and powdery mildew (Fig. 3) infections of this season on unsprayed ‘Ginger Gold’ and ‘Pink Lady’ trees here at AREC. The prevailing cold weather this spring, with brief snippets of warm, has severely slowed down disease symptom occurrence. In terms of scab, we never had a high pressure here at AREC to begin with and also we applied early fungicide applications on all blocks, so scab has not yet expressed regardless of the large amount of last years leaves with scab I introduced in our Fuji block. Alas, I hope to find it soon in any fallow orchards around AREC and report to you the first infections visible and the fungus will catch-up soon with warm weather predicted next week. One of the first signs, if you were to see apple scab on spur leaves of any unsprayed trees, are dark olive spots (Fig. 4).

FIGURE 1. CEDAR APPLE RUST ON ‘GINGER GOLD’ APPLE LEAF CAUSED BY THE FUNGUS Gymnosporangium juniperi-virginianae SHOWING ORANGE SPERMAGONIA AND SPERMATIA OF THE FUNGUS (PHOTO BY AĆIMOVIĆ S. G., 2022).
FIGURE 2. CEDAR APPLE RUST ON ‘GINGER GOLD’ APPLE LEAF CAUSED BY THE FUNGUS Gymnosporangium juniperi-virginianae SHOWING ORANGE SPOTS THAT CONTAIN SPERMAGONIA AND SPERMATIA OF THE FUNGUS (PHOTO BY AĆIMOVIĆ S. G., 2022).
FIGURE 3. SECONDARY INFECTION ON A LEAF OF ‘PINK LADY’ APPLE CAUSED BY THE POWDERY MILDEW FUNGUS Podosphaera leucotricha (PHOTO BY AĆIMOVIĆ S. G., 2022)
FIGURE 4. EARLY OLIVE GREEN SPOTS AS SIGNS OF INFECTION WITH APPLE SCAB FUNGUS Venturia inaequalis ON APPLE LEAVES (PHOTO BY S. G. AĆIMOVIĆ, 2017)