57 



In hot and moist summers Scab may destroy or reduce in value 25 to 30 per 

 cent, of the crop. There are two stages of the disease. One on the fruit, twigs, 

 and leaves in spring and summer causes deformations in some varieties of fruit 

 while the leaves are spotted or even curled up. Wind spores, or conidiospores, 

 spread the disease, but it winters on fallen leaves where the cup-spores develop 

 and are shed in the spring. 



The Pink Rot or mould, Cephalothecium roseum, which occasionally develops 

 on the scab spots, does most damage to fruit after storage, and is especially to 

 be feared in R. I. Greenings. 



The Bitter Rot, Glomerella rufomaculans, is thought to be the most serious 

 apple disease of the United States, where an epidemic in 1900 caused an estimated 

 loss of ten million dollars. The disease causes cankers on twigs and limbs, des- 

 cribed as sunken spots with broken or cracked bark. Spores from the cankers 

 infect the early diseased fruit, which then shows spreading lines of small brown 

 spots radiating from a centre. Pustules on the spots produce wind-borne spores, 

 spreading the rot to other fruit. There is also a perfect or ascus stage. The winter 

 may be spent in windfalls on the ground, but early summer infection is supposed 

 to be spread mainly from the cankers on the tree. Duggar says : " Bitter rot can 

 spread with alarming rapidity, causing enormous devastation within a week." 



Black Rot and Canker of the Apple, or New York Apple Canker, Sphaeropsis 

 malorum, was reported to this Society as being present in 1909, and occasionally 

 in 1910. It is characterized at first by a brown spot spreading over the whole 

 fruit. On the tree occur cankers or depressed withered spots upon the large limbs. 

 These are not always severe, but they may cause large wounds, girdle the affected 

 branch, and so kill it. Standard winter varieties are susceptible, such as Baldwin, 

 Wagener, Greening and King. The vegetative part of the fungus is brownish, and 

 the spore-bearing organs burst through the outer tissues as a pustule. The spores 

 are said to live as long as a year. 



Though not classed as a disease, being rather a feeder on dead tissues, Soft 

 Rot, or Common Blue Mould, PeniciUium glaucum, is a most destructive fungus 

 in stored apples. Entering the fruit by some wound, bruise or worm-hole, the 

 mycelium grows over the tissues and dissolves them, forming a greenish-blue mat. 

 Conidia or wind-spores are developed in chains or branched organs, while cup — 

 or ascospores — may also occur. Fruit in closed barrels is apt to suffer heavily 

 while awaiting re-packing, if kept at all warm. By storing no over-ripe or injured 

 fruit, Blue Mould can be avoided in part. When it begins it makes rapid progress, 

 even at low temperatures. 



While we have thus numerous diseases in stored apples, up to the present the 

 chief means of control is storage at low temperatures ; or, if the stock is to be 



