Pomaceous Fruits 69 



less prevalent in the South antl West than in the North 

 and East. 



The entire leaf area often presents a diseased appearance, 

 and there is no striking zonal arrangement in the infected 

 spots as in leaf-spot. Eventually the leaf yellows, or turns 

 brown and falls. The l)light may attack the fruit itself, caus- 

 ing a red spot, which in a later stage resembles pear scab. 



The treatment already recommended for pear seal) will 

 suffice for pear leaf-blight. 



Black-rot canker {Physalospora cydonice, Sphceropsis.). — ■ 

 In appearance and treatment this disease is similar to black- 

 rot of the apple. 



Minor diseases 



Pink-rot often follows seal). The cause and general rela- 

 tions are given under apple; Bark-canker, Frost injury, 

 Crown-gall, Sooty-blotch, Fly-speck, Black-mold, Brown- 

 rot, Texas root-rot, Hypochnose, Septobasidium canker, 

 Die-back canker, Alternaria, see apple. Bitter-rot is 

 identical with that of the apple but is of slight importance 

 on the pear. Red-leaf, a disease of unknown cause, has been 

 noted in New York. 



QUINCE.so 



Rust '^^' ■'"' '"•"' (Gymn.osporangium clavipes C. & P., Roes- 

 telia). — The quince rust, spring stage, agrees with apple 

 rust in general characters. The causal fungus grows upon 

 the fruit in the summer and produces there myriads of spores 

 which, on the approach of fall, are carried by the wind to ad- 

 jacent red cedar trees (Juniperus), and there produce swellings 

 upon the branches and twigs during the fall and winter. In 

 the spring, these give origin to masses of spores embedded in a 

 matrix of jelly. These spores are conveyed to the quince tree 

 by the wind, and there again produce the quince rust. The 

 cedar is a necessary resting place for this fungus during 

 the winter. 



