1192 THE FRUIT INDUSTRY IN NEW YORK STATE 



cavities of the winter fruiting-bodies, which are known as peri- 

 thecia. The perithecia contain numerous club-shaped sacs, each 

 of which in turn bears eight winter spores, or ascospores. By 

 March or April these spores are matured, and at this time, or 

 possibly a little later, they are shot during rainy periods from 

 the sacs through the openings mentioned above. The air currents 

 carry these spores to other limbs, and apparently they gain en- 

 trance on actively growing tissue or through wounds. The young 

 knots very soon begin to appear as previously described. 



About 1850, turpentine, kerosene, and other washes were ap- 

 plied to the knots, but forty years later k ' the heroic use of th< 

 knife " was the recognized remedy. The eradication of the knots 

 has been the subject of legal enactments in several states, including 

 New York.* 



In removing the knots, it should be remembered, first, that th( 

 summer spores are produced abundantly from May until Ia1 

 in the summer; secondly, that the winter spores develop late ii 

 winter or early spring and are discharged with the warm Apri 

 rains. Therefore, the knots should be removed before either ty] 

 of spores are produced; in other words, diseased limbs should 

 eradicated in the fall or early winter. Watch closely for th< 

 appearance of any young knots in the spring; these, if foun< 

 should be removed at once. Spraying alone for this disease 

 not effective. 



BROWN ROT 



The brown rot, caused by Scleratinia cinerea, is next in ordei 

 of seriousness among the diseases of the plum. It may be vei 

 destructive one year and of relatively slight importance the follow- 

 ing season. In years of full fruitage, accompanied by damp, wai 

 weather, the disease is most troublesome. But the weather is IK 

 the direct cause of the rot; a fungus is directly responsible, the 

 weather only offering the proper conditions for the developmenl 

 of the fungus. 



The fruits are the common seat of the injury, although th< 

 blossoms and twigs are quite susceptible (figs. 394 and 395). The 

 fruit is attacked as it approaches maturity, turning it brown, soft 

 and worthless. At first the rotted areas are small, circular, an< 

 brownish. These rapidly enlarge until they involve the entii 



* Section 304 of the Agricultural Law. 



