366 Worm aid. — ‘ Brown Rot ’ Diseases of Frtiit Trees . 
Massee again recognized one species only, referring to it as Monilia 
fructigena in his ‘ British Fungus-Flora’ (1893), and in ‘A Text-Book of 
Plant Diseases ’ (1903) ; later (1910) he describes it as Sclerotinia fructigena . 
Cooke (1906) also attributed attacks of Brown Rot on apples, pears, 
cherries, and apricots to one species, Monilia fructigena. 
Spinks (1915-16) has recently investigated ‘ A Black Rot of Apples ’, 
particularly with regard to its occurrence on cider apples, and finds that it 
is caused by Sclerotinia fructigena , in the restricted use of this name as 
defined by Woronin ; this disease is probably identical with the one 
observed by Worthington Smith (1885). 
In 1907 Salmon recorded outbreaks of Brown Rot on acid cherries, and 
in 1910-14 called attention to a serious ‘Brown Rot 5 disease which destroys 
the blossom of apple trees and may invade the branches and produce 
cankers. The present writer (1917) undertook the further investigation of 
epidemic attacks of this ‘ Blossom Wilt and Canker Disease ’ of apple trees, 
which was particularly prevalent on the variety Lord Derby in the Weald 
of Kent, and found that the fungus responsible was not Monilia fructigena , 
which had been assumed to be the species causing the disease, but a grey 
Monilia conforming to descriptions of M. cinerea , Bon. Later a ‘ Wither 
Tip of Plum Trees ’ (1918) was found to be caused by a fungus morpho- 
logically similar to that occurring on ‘ Brown Rot Cankers ’ of apple trees, 
but was different from that form biologically, in that it was unable to 
establish itself in the flowering spurs of the apple, and so was incapable of 
inducing the typical ‘ Blossom Wilt ’ condition or of forming cankers on 
apple trees. 
Meanwhile phytopathologists in the United States had been attracted 
to the investigation of outbreaks of £ Brown Rot ’ in America, where fruit- 
growers were subjected to great losses annually, caused by a species of 
Monilia , peach trees proving particularly susceptible to the disease. Peck 
(1881) found that Oidium fructigenum attacked the fruit through wounds, 
for he was unable to produce infection by placing conidia on the uninjured 
skin. In 1886 Arthur recorded a blossom infection of cherries in New 
York as having occurred during the previous summer, and three years later 
Erwin F. Smith (1889) described a blossom blight of peaches as caused by 
Monilia fructigena , another paper on the same subject by the same author 
appearing in 1891. In that year Humphrey also wrote on ‘ The Brown Rot 
of Stone Fruits ’, and he too referred the fungus to M. fructigena , which 
he believed to have a conidial stage only. During the nine years following, 
further papers by Humphrey appeared, and other investigators took up 
the work, e.g. Chester (1892), Taft (1894), Bailey (1894), Goff (1897), 
Quaintance (1900), Waugh (1900). 
In 1902 Norton made an important discovery when he found the 
ascigerous stage of the Brown Rot fungus occurring on peaches in Maryland ; 
