102 CBOWN-GALL OF PLANTS. 



HAIRY-ROOT ON TOMATO, 



Inoculations of November 21, 1908 (Brown). 



In connection v,dtli the inoculations of the apple-gall organism 

 into the adventitious roots of tomato, the hairy-root organism was 

 also tried on tomato. The tomato plants were of the same sort 

 as those used for the apple-gall inoculations, viz, a small, red, hot- 

 house variety, 5 feet tall and in fruit. The stems about halfway 

 down the plant showed bulgings where roots might possibly pro- 

 trude, and adventitious roots projected a distance of one-eighth to 

 one-fourth inch. Both the bulging places on the stem and the 

 smallest adventitious roots were inoculated from agar streak cul- 

 tures 3 days old. Three plants were inoculated, more than a dozen 

 places on each being punctured. 



Two check plants were held, the punctures being made in the same 

 way as those of the inoculations. 



Result. — December 10, 1908: No trace of hairy roots or galls on 

 the plants inoculated with the hairy-root organism. 



December 22, 1908: No galls or hairy roots formed on the adventi- 

 tious tomato roots inoculated with the apple hairy-root organism. 



The checks remained healthy. 



Inoculations of December 10, 1908 (Brown). 



A second test of the apple hairy-root organism on tomato was 

 made, much younger plants in a better growing condition being 

 inoculated with 3-day-old cultures of the hairy-root organism. The 

 nascent roots on the stem were treated in the same way as the first set. 



Result. — January 2, 1909: No effect produced on the stem of the 

 plant or on the nascent roots by the inoculation. 



Inoculations of April ], 1909 (Brown). 



Ten young tomato plants about 6 inches tall were inoculated with 

 agar streak cultures of the apple hairy-root organism 2 days old. 

 The crown of the root, the middle of the stem, and the growing point 

 of the stem were inoculated. Four checks were lield. 



Result. — ]\Iay 2, 1909: Examined tlie plants and found that 6 had 

 roots projecting in a cluster, but whether these were adventitious 

 roots put out to liold the plant in position or due to the j^resence of 

 the organism could not be determined. The checks had not these 

 decided rootlets, but the inoculated plants did not always have the 

 rootlets in the immediate area of the puncture. The ])lants Avore 

 re[)lace(l in larger pots and left to grow. 



September 3. 1909: Decided that no hairy roots had formed. 

 2i:i 



