A Bacterial Disease of Stone Fruits 397 



In 1909, at Mountain Grove, cross inoculations with the four strains 

 obtained from the leaves were made on eight-years-old Royal apricot, 

 Victoria nectarine, Elberta peach, and Abundance plum trees. Two 

 hundred leaves, fifty fruits, and twenty twigs were used in each case. 

 The organism from young-slant Hiss-glucose cultures was thoroughly 

 mixed with sterile water and sprayed on the leaves and the fruit with 

 an atomizer. Each of the twenty twigs was inoculated at four points 

 with a hypodermic syringe. Spots appeared on the leaves of all the 

 inoculated trees in ten days, and on the fruit in from twelve to fifteen 

 days. The inoculated tissue on the twigs assumed a water-soaked appear- 

 ance in from four to eight days, becoming dark brown and finally, in 

 about twenty-five clays, almost black. Poured plate cultures from the 

 spots on leaves, fruit, and twigs yielded numerous colonies of the yellow 

 organism. Three of the check leaves on peach also developed a number 

 of brown spots. 



In 1910, at Mountain Grove, cross inoculations with strains of the 

 organism from the fruit of the four hosts were made on eight-years-old 

 Royal apricot, Victoria nectarine, Elberta peach, and Burbank plum 

 trees. Fifty leaves and ten twigs were used in each case. The organism 

 from young-slant Hiss-glucose cultures was scraped into sterile water. 

 The fingers were dipped into this water, and the material was applied to 

 the lower surface of the leaf by gently rubbing the leaf between thumb 

 and fingers. Each twig was inoculated at six points with a hypodermic 

 syringe. Gray spots appeared on the leaves of all trees in from six to 

 seven days, and water-soaked spots appeared in great numbers about 

 the tenth day. The inoculated tissue on the twig assumed a water- 

 soaked appearance in from five to seven days and became dark brown in 

 about twenty-five daysi Poured plates from the spots on leaves and twigs 

 yielded colonies of the organism more or less abundantly. All the twig 

 check wounds soon healed, and the check leaves remained free from spots. 



In 1911, at Ithaca, New York, cross inoculations with the four strains 

 obtained from the twigs of the four different hosts were made on three- 

 years-old Elberta peach and four-years-old Abundance plum trees. The 

 organism from young-slant Hiss-glucose cultures was thoroughly mixed 

 with sterile water and sprayed on the leaves with an atomizer. Twelve 

 twigs were used in each case, and each twig was inoculated at five points 

 with a hypodermic syringe. Spots on the leaves developed in nine days, 



