How to Manage Pests

Apple measles

Apple measles occurs in California's coastal areas, most frequently on 'Red Delicious'. Measles first appears as small, red pustules on the smooth bark on young twigs. Tissue in the centers of the pustules is dead, and the lesion extends into the cortex or to the phloem tissue on the inside of the bark. Surface tissue of the bark may thicken, crack, and slough off over a large area, resulting in scurfy cankers. Slicing into the roughened bark reveals brown flecking or streaking of internal bark tissue. Cracking and sloughing of the bark surface may continue for several years.

Solutions

Apple measles symptoms are an expression of manganese toxicity, caused by acid soil. Applying lime may alleviate measles symptoms, but it is usually difficult for trees to recover.

Small red pustules on young twigs

Older apple measles lesions