EXPERIMENTS WITH THE PEACH ORGANISM. 71 



Nine trees of the same kind were punctured for control. 



Result. — November 24, 1908: Of the inoculated Kansas, 10 trees 

 made no growth, 12 were missing, and 1 out of the remaining 12 

 bore a knot. Of the supposed controls, 5 made no growth, 14 were 

 missing, 6 bore knots, and 10 were free. 



Of the inoculated Virginia only 4 bore knots; 5 only of the controls 

 were found. On these there were no knots. 



All of these trees were grown on the Arlington Experimental Farm. 

 They were dug, washed, inoculated, and replanted at Arlington. 

 Doctor Townsend superintended the washing and inoculation, but not 

 the replanting. The soil in which the trees had grown, and in which 

 they were replanted, was believed to be free from the gall organism. 

 The appearance of galls on the trees marked as checks was attributed 

 to the workman's having mixed checks and inoculated trees at the 

 time of replanting. The failure of this experiment emphasizes the 

 necessity of safeguarding every step of an experiment. 



PEACH ON RED RASPBERRY. 



Inoculations of May 20, 1908 (Brown). 



Nine young red raspberry bushes in a good growing condition in 

 pots in the greenhouse were inoculated with agar streak cultures 2 

 days old. Seven plants were inoculated on the crown and on the 

 stem. Two plants were inoculated on the crown only. Four checks 

 were pricked on crown and stem. 



Result. — June 12, 1908: One hundred per cent of infections. Four 

 of the 7 plants inoculated on crown and stem bore knots on both 

 crown and stem, wliile the other 3 had knots at the crown only; of 

 the 2 plants inoculated only on the crown, both bore knots. Those 

 plants inoculated on the stem received 2 to 3 groups of pimctures, 

 each one yielding a gall. 



No galls formed on the 4 checks. 



PEACH ON BLACK RASPBERRY. 



Inoculations of May 19, 21, 22, 1908 (Brown). 



Thirty-four plants were inoculated, as follows: 



May 19. Ten young black raspberry bushes in a good growing con- 

 dition in pots in the greenhouse were inoculated with agar streak 

 cultures 8 days old; 6 plants, both on the crown and on the stem; 4 

 plants, on the crown only. Four checks, punctured on both crown 

 and stem, were held. 



May 21. Twelve similar plants were inoculated at the crown and 

 on the stem \\rith agar streak cultures 3 days old. 



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