6 A. L. PlERSTORFP 



shoots blighted so rapidly with the characteristic symptoms of fire 

 blight thai no further inoculations appeared to be necessary. This 

 work confirms the findings of Arthur (1885a) and of Waters (1921), 

 .•md, judging from the extended killing of the hedges, one would con- 

 clude that C. oxyacantha is highly susceptible to Bacillus amylovorus in 

 New York. 



INOCULATIONS ON STRAWBERRY 



(Fragaria chiloensis Duchesne, var. ananassa Bailey) 



Following the work reported by Munn (1918), the writer sought to 

 obtain additional information concerning the pathogenicity of Bacillus 

 amylovorus for strawberry blossoms, leaves, crowns, fruits, and runners. 

 Strawberries of the varieties Chesapeake and Premier, and of one 

 unknown variety (hereinafter designated as variety X), were used for 

 all greenhouse tests. 



On February 2, 1925, six blossoms of each variety were inoculated 

 in the greenhouse by puncturing with a sterilized needle dipped in a 

 three-days-old bouillon culture. Three days after inoculation, four of 

 the inoculated blossoms, two of Premier and two of the variety X, 

 appeared water-soaked and light brown in color. In eight days these 

 blossoms had turned almost black and were badly shriveled. The pedicels 

 of the blossoms had turned black for a distance of about two inches from 

 the flower. Isolations made from two pedicels about one inch below 

 the blossoms yielded the fire-blight organism, which was checked by 

 inoculation into apple seedlings. 



On March 3, 1925, ten blossoms of each of the three varieties were 

 inoculated by atomizing with a bouillon culture of the organism ; nine 

 days later three of the Premier blossoms, two of the Chesapeake, and 

 four of the variety X, were dead. In another test, five berries six 

 days old, of the variety X, were inoculated with a needle; six days 

 after inoculation, four of the fruits had been killed by the blight 

 organism. In Plate I, 1, a blighted fruit is shown on the right and a 

 healthy fruit on the left. The writer was unable to produce infection 

 in half -grown or maturer fruits. 



On March 9, 1925, one hundred leaves, thirty runners, and the crowns 

 of twenty-four plants, were punctured with a needle dipped in a culture 

 of B. amylovorus. Half of the plants were left in the greenhouse, and 

 the other half were placed in a moist chamber in the headhouse for 

 twenty-four hours and subsequently removed to the greenhouse. This 

 experiment was repeated on March 21, but no infection was detected 

 in any of the leaves, runners, or crowns. The cultures used were 

 pathogenic to apple seedlings. 



