312 MANUAL OF FRUIT DISEASES 



York. The distribution in America would appear rather 

 limited. It occurs widely in Algeria on apricots, peaches and 

 cherries ; in France on almonds ; in Australia and New Zealand 

 on plums and other stone-fruits ; and in Europe commonly on 

 cherries. 



This blight disease constitutes a well-known and important 

 factor in peach growing throughout California. ' Most damage, 

 however, is wrought in the more humid localities, where no 

 variety seems to be immune. l Trees are more or less weakened, 

 depending on the severity of the attack, and frequently crops 

 are destroyed. Buds are killed, green fruiting twigs are spotted, 

 and leaves are dwarfed. Premature defoliation is not at all 

 uncommon t 



Symptoms. 



The effects of the Coryneum-blight are shown early in the 

 spring. This is particularly true under California conditions. 

 ^ The most evident symptoms of blight consist in a gumming 

 and death of the buds on the fruiting wood, accompanied by a 

 splitting of the bark on branches of the current year's growth. 

 Affected buds may die before spring and thus fail to start, or 

 they may start and die later after the young fruit sets. Blighted 

 twigs become spotted, and an exudation of gum ensues ; finally 

 death occurs: The spots may show as early as the first of 

 February, at least in California. These are depressed areas 

 in the bark, and are in reality cankers. The leaves may be 

 affected when young. The lesions produced are circular, 

 brownish spots, with dark-red margins; finally the affected 

 tissue falls away, leaving a hole in the leaf where each dead 

 spot first occurred. Where several such holes occur there 

 results a shot-hole appearance. This shot-holing is more 

 common as a result of the first lesions produced ; lesions de- 

 veloped later in the season do not exhibit this peculiarity. On 

 the latter spots small grayish tufts of the pathogene may be 

 seen. Lesions produced on peach-fruits resemble somewhat 



