76 CEOWN-GALL OF PLANTS. 



the 12 inoculated plants. These knots were under the pieces of 

 cotton, placed over the punctures, so there was no mistaking the 

 infection. The checks had no knots. These roses were not making 

 a rapid growth. 



Remarks. — The rose is rather difficult to infect. Probably if one 

 knew just the right age and stage of growth infection might not be 

 difficult, since some varieties of rose are very liable to contract this 

 disease in hothouse culture, the Killarney in our experience being 

 one of them. 



Inoculations of January 15, 1908. 



Twelve Killarney rosebushes were inoculated with agar streak 

 cultures 1 day old. The soil was laid back from the crown of the 

 root, and the root washed carefully with sterile water before inocu- 

 lating. Fifteen needle pricks were made on each root. Each inocu- 

 lated spot was covered with a piece of moist cotton. 



Result. — February 3, 1908: Only 1 root had a gall. 



April 17, 1908: The entire lot was again examined carefully, and 

 but 1 other gall found. This one was taken to the laboratory and the 

 organism was obtained from it by poured agar plates. 



Inoculations op March 18, 1908. 



Six young, healthy Rambler rosebushes were inoculated by needle 

 pricks with agar streak cultures 2 days old. The plants were taken 

 from the pots, the soil removed, but not washed, so that none of the 

 fine rootlets were broken off. 



Result. — April 6, 1908: The plants were taken from the pots and 

 examined but no knots were found. The growth had been slow. 

 (For checks, see Rose on Daisy, p. 75.) 



Remarks. — Of .30 rose plants inoculated only 4 contracted the 

 disease. 



ROSE ON PEACH. 

 Inoculations of January 14, 1908 (Townsend and Brown). 



Eight young peach trees were inoculated at the crown with slant 

 agar cultures 1 day old. Twenty-five punctures were made in each 

 tree in groups of 5. Four trees were held as checks. The work was 

 done in the laboratory and the trees planted immediately afterward 

 in pots in the greenhouse. The trees were dormant at the time of 

 inoculation and probably remained so long enough to interfere with 

 the infection. 



Result. — April 6, 1908: The trees were taken from the pots, 

 washed, and carefully examined. No galls were found on any of 

 the trees. 



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