8. F. Armstrong 87 



Condilion <if the phints on June 2nd, 1 920. 



By this date rust attack was at its height and the state of the beds 

 was very interesting (Table XII). 



It will be seen that every plant of Burbank's, Wilhelmina, and the 

 two extracted susceptible types was rusted. On Wilhelmina the attack 

 was generally speaking of a moderate character; on the other susceptible 

 varieties it was very severe. The two extracted rust-resistant types and 

 American Club continued to show very high resistance to attack, but 

 in a few cases this resistance had apparently been more or less broken 

 down. These cases will be noticed after first comparing the number of 

 such apparent "breakdowns'" on the different beds. 



On bed D there were 83 plants of the immune varieties, and these 

 all remained completely rust-free ; not the shghtest sign of infection could 

 be found throughout the season. 



On bed C only one plant was "flecked" out of a total of 14. Out of 

 15 plants on B 7 either bore pustules or were "flecked," while on bed A 

 17 plants were either "flecked" or bore pustules out of 93 individuals. 

 The percentage of more or less successful attacks at this date on beds 

 D, C, A and B was therefore respectively 0, 7, 18 and 40. These results 

 point in the same direction as those given above for the number of 

 early infections recorded among the susceptible varieties on the same 

 beds. 



These cases of infection were distributed among the "immune" 

 varieties as follows: 17 cases occurred out of the 118 American Club 

 plants; 6 occurred amongst the 45 plants of 66/9/f/; while only 2 cases 

 were met with out of 42 plants of 82/14/a. 



The following particulars may be given of the individual plants 

 concerned. 



American Club. On bed C (row (i) 1 jilant was slightly flecked. On 

 bed A (row 2) 3 plants were clearly flecked though no pustules were 

 formed. In row 6, out of 22 plants, 6 showed signs of infection. Plant 

 No. 5 had a pronounced attack — though chiefly confined to one leaf. 

 On this single blade, 71 well-developed pustules were counted, every one 

 shedding spores, in addition to 17 other unbroken pustules. Plant Ifi, 

 besides being flecked, bore three large pustules, one of which was shedding 

 spores. Plant 19 had 7 well-developed pustules, 4 of which were broken, 

 besides numerous flecks. Plants 6, 10 and 22 were flecked. In row 10, 

 plant 2 was flecked and bore 47 pustules, many of which were broken. 

 Plant 9 bore flecks and 2 unbroken pustules. Plants 12 and 15 were 



