104 .1 Blo^mm Wilt and Ccmher of Apple Trees 



apple trees which, from tlie description, appears to be identical with 

 that observed in this country. He found that the Monilia pustules 

 which developed on the affected parts w^ere grey in colour but states 

 that he makes no distinction between Monilia cinerea and M.frucfigena, 

 and assumes that the form which appears on the fruit in autumn is a 

 stage in the annual cycle of that form which kills the twigs and blossoms. 



Broz(6) in 1913 describes the occurrence of the " Zweigdiirre *' at 

 Vienna and states that late frosts favour the outbreak of the disease. 



Brown Rot is also known in America where it is particularly de- 

 structive to peach trees, killing blossom, fruit and branches. The 

 American form, though it has been generally^ named Sderofinia frucfi- 

 gena, is found by the iiiore recent investigations of Matheny (U), Jehlo(i2), 

 Conel(T), and Bartram(n) to conform more nearly to the descriptions 

 given of S. cinerea, and is referred by them to that species. 



In our own country it has been customary to' refer all cases of Brown 

 Rot of fruit trees to Monilia fructigena, and although the Monilias are 

 probably responsible for greater losses to the English fruit growers 

 than any other genus of fungi (since in one form or another it attacks 

 the blossom, young fruit, ripening fruit, fruit in the store, twigs and 

 branches), no attempt appears to have been made until quite recently 

 to determine whether the conclusions arrived at by Continental workers 

 hold good for Britain. 



In 1903 Mr G. Massee observes (13) that Monilia fructigena "is most 

 frequently seen on apples and although best known to the casual observer 

 on the fruit occurs also on the young shoots, leaves and even the flowers.'' 

 That Monilia is capable not only of killing the flowering spurs but may 

 also produce large cankers on the main limbs of apple trees was recorded 

 by Mr Salmon (16) in 1910. Since that year many specimens of Blossom 

 Wilt and Brown Rot canker have been sent to Wye College, and it was 

 evident that the disease was becoming a serious menace to the cultiva- 

 tion of some varieties of apples in certain districts, particularly in Kent. 



Mr Salmon has, on several occasions 2, pointed out the serious nature 

 of this form of Brown Rot ; since preliminary examination showed that 

 the results of investigations made abroad were not wholly in accordance 

 Yvith observations made on the disease as affecting apple trees in this 

 country it was evident that it w^as a subject demanding further research, 

 and as Mr Salmon himself, from pressure of other duties, was- unable to 

 continue the work, it was entrusted to the present writer. 



^ Vide Duggar's Fiivgous Disen.^r.'i of Plmit.", footiioto on pace 187. 

 - See Bibliographj^ on p. 203. 



