90 Disease of Fruit Blossom 



at this institution, including the following kinds : Beurre d'Aman- 

 lis, Catillac, Vicar of Winkfield, Louise Bonne de Jersey, Conference, 

 Bellissime d'Hiver, Dr Jules Guyot, Williams' Bon Chretien, and 

 Pitmaston Duchess. Of these sorts the two first named are much more 

 badly attacked than the remainder ; and most of the trees of those 

 kinds, although covered with blossom, produced very few fruits in 1913, 

 some indeed failing to yield a single pear. After examination of the 

 older fruit spurs of the trees of all of the varieties named, it is evident 

 that also in years prior to 1913 the two varieties in question have suffered 

 more severely than the other kinds. 



In the case of apples discoloured flowers of Beauty of Bath, Bramley's 

 Seedling, Allington Pippin, Devonshire Quarrenden, and Duchess of 

 Oldenburgh have been examined, and from each sort the bacillus has 

 been isolated. There is not sufficient information available yet to show 

 if some varieties are more susceptible than others. Few kinds of plums 

 have yet been examined ; but cultures of the bacillus have been obtained 

 from the Victoria variety and the Myrobella plum. Only two cases of 

 cherry blossom have been examined, viz. the Norwegian cherry and a 

 kind sent through the Board of Agriculture without name. In both 

 instances the organism was isolated. 



There is little doubt from the specimens of fruit blossoms examined 

 last year that the disease is very widely spread. Not only was it re- 

 peatedly found in the immediate neighbourhood of Bristol, but also in 

 many other parts of the country. The bacillus has already been isolated 

 from affected pear flowers sent to us from Devon, Teddington, Wolver- 

 hampton, Stroud, Ross, and Offenham ; and from apple blossom sent 

 from Berkeley, Ledbury, Elsenham, Essex, and Hailsham. The 

 occurrence of the organism over so wide an area suggests the probability 

 of a general distribution throughout the midland and southern counties 

 at least ; and the fact that it has been isolated from a number of plants 

 other than pears and apples, in which blossom or foliage damage was 

 slight, raises the question of its pathogenic character in all cases. 



It undoubtedly is responsible for the disease of pear blossom in the 

 forms already described, since branches of pear trees carrying unopened 

 and undamaged blossom have been brought on under greenhouse con- 

 ditions and have in due course borne flowers which have developed the 

 disease both after artificial inoculation with the bacillus and in many 

 cases without deliberate infection. Also abnormally late blossoms 

 produced in the open in June have been found to be affected. In such 

 instances the possibility of frost damage has been excluded, care having 



