Lesion expansion occurs slowly on older leaves. Affected leaves may also exhibit black streaks along midribs and veins. Leaves displaying this symptom may al be crinkled along the midvein or margin. Petioles and stems may be girdled by black lesions and the tissue beyond this point withers and dies. Tissue directly affected by syringomycin turns black and exhibits water-soaking while those that die as a result of girdling turn brown.
Dead shoots bend, forming a shepherd's crook.
Twigs that become woody before infection occurs have lesions comprised of black streaks that run lengthwise. Flower clusters often blight rapidly when infected and turn black. The rest of the inflorescence turns dark brown and limp. Plant Health Management Sanitation. Prune out infected twigs several inches below the margin of healthy and infected tissue.