: ;r THE PLUMS OP XKW YORK. 



prevention or core are not established though all agree that sofls may be 

 inoculated with the disease from infected stock; hence the nM^sfty of 

 discarding diseased trees at transplanting time. 



Smith found in Michigan and Clinton in C"""**AkTil a disease of the 

 fruit called bacterial black spot 1 (Pstmdomtmas fnuu Smith) of the same 

 generic origin as the crown gall but widely different in nature. The writ- 

 ers and the growers who found the infected fruit, saw the disease only on 

 the Ttiflora plums., It attains the giuui fruits which show conspicuous, 

 black-purple, sunken spots sometimes as large as half an inch in diameter. 

 The injuries are usually isolated and quite superficial but nevertheless, 

 spoil the fruit. 



The phnn in *-rm*nrm* with other stone-fruits often suffers from an 

 excessive flow of gum, for which trouble the name gnmmosis* is now 

 generally applied. The disease is to be found wherever plums are giuwu 

 but it is much more destructive on the Pacific than on the Atlantic sea- 

 board. So far as is now known, gnmnxxas is secondary to injuries caused 

 by fungi, bacteria, insects, frost, sunscald. and mechanical agencies. The 

 disease is least common in species and varieties having hardwood; on 

 UULI> on sofls favoring the maluiii^ of wood; under conditions where 

 son and frost are not injurious; and. obviously, in orchards where by 

 good care the primary cantsts of gumming are ktjA out. Stewart* has 

 recorded an interesting case of gum-pockets in the fruit, but could assign 



injuries uofu. the 5* 1 **), fiosA and hail are 1 rrnihln 

 which nearly aH plum-growers must contend at one time or another. La 



..- - ft - _ f*m ____ - : __ : _ 1 .,,. ** 



me mvevne \jauoe ano. innora iii"iii^^ suner 



bat none are wholly immune, M 1 * 1 !*^ 1 Tximlaiid is possibly most so. These 

 injuries from the dements of weather are often mistaken for diseases. 

 and are so often foubwed by fungal parasites and insects as to make it 

 difficult to ilfflinjMHfili the primary from the secondary trouble. Low- 

 heading of the trees is the best preventive of these trunk injuries. 



Prams are somewhat subject to attacks of the well-known peach 

 scab (Cladosporimm tarfofkHmm Thumen). The scab appears in numer- 

 ous, small, sooty, circular spots of Uomuisib color, often confined to one 



