Starts to be visible in crop fields by early bloom, later in June in prune fields.
Isolated patches of stems are affected.
Leavers are bright red (sometimes not the whole leaf), and leaf may be slightly thickened.
About the end of June, white spores are produced on the underside of infected leaves.
Key Symptoms: Bright red leaves, with color not just at tips of leaf. Slightly thickened leaves, later white underside of affected leaves.