PEACH SCAB AND ITS CONTROL. 61 
Furtliermore, since even on the worst affected varieties the disease 
may be efficiently and economically controlled by spraying, the use 
of varieties which are in some degree disease escaping or resistant 
is unnecessary, though advisable when other factors are equal. 
SUMMARY. 
Peach scab {Cladosporium carpophilum Thiim.) manifests itself in 
serious spotting and cracking of the fruit and superficial injuries on 
twigs and leaves. 
In the United States the disease has been reported from 34 States, 
which include practically every important peach-producing district 
east of the Kocky Mountains. Its occurrence has also been recorded 
in Austria, Canada, Holland, Australia, southern Europe, and South 
Africa. 
Among the fungous diseases of the peach in the United States east 
of the Rocky Mountains, scab ranks next to brown-rot in economic 
importance. In many sections, before satisfactory control measures 
were developed it rendered unprofitable the growing of certain valu- 
able commercial varieties. Unless controlled, it would be a serious 
menace to successful commercial peach culture in many of the most 
important peach-producing districts of the Southern, Eastern, and 
Central States. 
The peach-scab fungus was first described by Von Thumen (1877), 
who assigned it the binomial Cladosporium carpophilum. Oudemans 
(1901) described as Fusicladium carpophilum Gud. a fungus growing 
on fallen young peaches. He fists as a synonym Cladosporium carpo- 
philum Thiim., but neither gives Von Thumen credit for the specific 
name nor states his reasons for transferring the fungus to the genus 
Fusicladium. Aderhold (1901) expressed the belief that C. carpo- 
philum TMm. and C. cerasi (Rbh.) Aderh. are identical, but he 
admittedly failed to adduce sufficient evidence to justify this con- 
clusion. Until further evidence is presented, the writer accepts the 
name Cladosporium carpophilum Thiim. for the peach-scab parasite. 
The primarily important diagnostic characters of the fungus are 
the short, erect, more or less flexuous, one to several septate, rarely 
branched, olivaceous conidiophores and the ovate-fusiform, obtuse to 
apically subacute, continuous or 1-septate, fight fuscous conidia, 
which are borne acrogenously, singly or in simple or branched chains. 
The fungus was isolated from peach fruit, twigs, and leaves, respec- 
tively, in single-spore strains, which were grown comparatively upon 
more than 30 media. The cultural differences between strains from 
different organs of the host were no greater than those observed in 
strains from the same organ. The fungus grew well upon this wide 
range of media and showed only minor variations upon the different 
substrata. 
