30 A. L. PlERSTORFF 



ism, concluded that "the germs of the disease gained entrance to the 

 interior of the branches through the newest growth of the young shoots 

 and the central parts of the flower, especially the moist nectariferous 

 surfaces." Waite (1896:298) suggests that bees, wasps, and flies 

 undoubtedly carry the microbe from oozing cankers to the blossoms, 

 and states (page 297 of reference cited) that the microbes "are able 

 to live and multiply in the nectar of the blossom." The last-mentioned 

 fact has been observed by other workers and unquestionably substan- 

 tiated by Gossard and Walton (1922). 



In order to determine whether infection would occur when other 

 parts of the blossom than the nectaries were inoculated with the fire- 

 blight organism, a number of branches of Rhode Island Greening 

 apples and Bartlett pears were brought into the greenhouse in the 

 latter part of March, 1925, and placed in battery jars containing 

 water. In about two weeks the branches blossomed profusely, and on 

 April 14 inoculations were made with a bouillon culture of Bacillus 

 amylovorus in the following ways: (1) by brushing the center of each 

 petal with a camel's-hair brush; (2) by puncturing the center of each 

 petal with a needle; (3) by puncturing the base of the blossom with 

 a needle; (4) by brushing the stigmas with a very fine camel's-hair 

 brush; (5) by atomizing into the center of the blossom. The results 

 of the inoculations are given in table 5. 



The average temperature of the greenhouse was about 65° F. No 

 insects were noticed on the branches. Aphids were abundant on the 

 opening buds but were killed by fumigation shortly before the blossoms 

 opened. Results similar to those shown in table 5 were obtained by 

 another series of inoculations made in the latter part of April. 



It was recognized that the conditions of the cut branches, and their 

 environmental influences, were entirely unlike the conditions prevail- 

 ing in nature. For this reason, similar tests were made during the 

 blossoming period in the Preswick and the Slater Brothers' orchard, 

 at Ithaca and Rochester, New York, respectively. In addition to bou- 

 illon cultures, fresh bacterial ooze also was employed. Inoculations were 

 made on branches covered with cheesecloth bags. Some inoculations 

 were made also on unprotected blossoms, and comparable results were 

 obtained but they are not recorded here since there is no assurance 

 that insects did not inoculate these blossoms. The data are recorded 

 in table 5. The weather records covering the blossoming period for the 

 Preswick and the Slater Brothers' orchard in 1925 are given in table 9 

 (page 42). 



Again, in 1926, stigma and petal inoculations were made in the Pres- 

 wick orchard and the Slater Brothers' orchard (table 5). The blossoms 

 were inclosed in glassine bags, to prevent the possibility of rain wash- 



