Pest Spotlight: 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."