shot_hole_fungus

PEST TYPE

  • fungus Wilsonomyces carpophilus
  • aka Coryneum blight
  • other bacteria and fungi cause similar symptoms, collectively known as "shot hole diseases"

COMMONLY AFFECTED TREE SPECIES

  • Ornamental cherries
  • Stone fruits
  • English laurel

DAMAGE/ SYMPTOMS

  • Purple-brown spots on young leaves
  • The infected spots eventually drop out of the leaf, creating the "shot holes"
  • Stem cankers provide overwintering site
  • Spotted, deformed fruit

MANAGEMENT

CHEMICAL:

  • Copper fungicide or chlorothalonil, available at A Plus by request
  • Apply in winter after leaf drop and before bloom
  • If severe, apply a second time during full bloom before petal drop

CULTURAL:

  • Remove old fruit and all infected wood
  • Prevent sprinklers from wetting foliage

BIOLOGICAL:

  • None

RHYME ZONE

"Look closely at those little purple-brown spots,
soon they'll fall out as though the leaf were shot."