110 PROTECTION. OF PLANTS — 1922-23 



Field Inoculations. 



On August 8th, 1921, some twenty-five pure cultures were transferred to 

 agar slants and incubated at 7°C for twenty-four hours. The cultures were 

 then taken to Montreal where they were used for the artificial inoculation of 

 some wild Iris plants which had been located at the edge of a swamp in the 

 outskirts of the city. The inoculations were made by needle pricks in the base 

 of the stem just below the surface of the ground. These opei-ations were carried 

 out late in the afternoon, so as to give the organisms the best possible chance of 

 becoming established before they became affected by the intense heat of the sun 

 during the day. The inoculated plants were carefully observed every day for 

 two weeks and twice during the third week. At the end of this period, no visit 

 ble infections were observed. 



On August 16th., day-old culturete were obtained from the twenty-five 

 organisms mentioned above, and inoculated in the same manner as above into 

 cultivated Iris plans on the College campus. These inoculations were observed 

 to regular intervals of two days for three consecutive weeks. At the end of this 

 period, nothing but negative results were obtained. 



The writer is unable to explain the reason for these negative results, but it 

 was probably due to the dr}' environmental conditions which prevailed at the 

 time of inoculation. Although the wild plants were located in a damp field, 

 the entire three weeks during which the observations were taken were extremely 

 dry, there being only one slight shower during the period. Similar conditions 

 also existed aftei the cultivated plants had been inoculated. Although the 

 inoculations were made late in the afternoon to give the organisms the bes- 

 possible conditions to produce infection, it is not at all unlikely that the dry 

 heat of the ensuing days inhibited their pathogenic action and finally killed 

 them entirely. 



Tansplanting. 



Before the ground was frozen in the fall of 1921, some four dozen plants 

 were removed from the field and planted into five inch pots with good green- 

 house soil. Half of these plants were placed in cold storage and the remainder 

 were placed in the greenhouse where the temperature ranged from 65°-70°F 

 These latter plants were given a month in which to become established before 

 inoculations were made. 



Petri Plate Cultures. 



To test the pathogenicity of the isolated organisms before trying to infect the 

 Iris plants in the greenhouse, inoculations with all the organisms were made on 

 slices of raw yellow carrot and also slices of Iris rhizomes. The medium to be 

 used was cut into slices about I/4 inch thick and washed thoroughly in distilled 



