Life histories of two little known parasites of the apple and pear

Abstract

The Sooty Blotch is a very common fungus upon the fruit of the apple and pear. It was first reported by Schweinitz in 1831 from Pennsylvania. Since then it has been reported from all parts of the United States and Europe. The Sooty Blotch first appears on the apple in the late summer when it has passed the stage of medium growth. It is a superficial parasite which does not penetrate the cuticle of the apple, breaking down the tissues; but merely roughens the outer surface of the cuticle. The fungus is easily recognized by the pale to deep black blotches that appear superficially upon the apple. These blotches are irregular in outline, in many cases coalescing to form large areas. Sometimes closely associated with this fungus there is another whose appearance upon the surface of the apple has suggested for it the common name "The Fly-Speck Fungus". Although these two fungi are commonly found together, in many cases only the one may be found. This fly specked and blotched appearance of the apple is prevalent in most orchards, it extent depending upon the variety, the weather conditions, and the situation of the orchard. Such an affection of the pear is not so prevalent, though the extent of the fungus depends upon very much the same conditions.