38 



James Stewart Wiant 



Spring applications of dusts made directly on the surface of fall-sown plats 

 just prior to emergence, were approximately as effective as the fall treat- 

 ments. Dusting the seed alone was practically without effect. 



An experiment was conducted on red pine during the season of 1927 

 with dry applications of aluminum sulfate and a number of organic and 

 inorganic mercury materials (table 11). The experiment was comparable 

 to experiment A of the liquid treatments of the same season. 



Many of the mercury treatments were effective in reducing the disease 

 from 67.7 per cent, as noted for the checks, to an almost negligible amount. 

 From a consideration of the percentage of damping-off and the final stand 

 (figure 3), it would appear that the best results were obtained with the 



Figure 3. final stand of red-pine seedlings in plats treated with dry applications 



of chemicals 



The numbers below the columns refer to the treatment numbers given in table 11 



two treatments with Bayer 1 1-6, the heavier application of mercuric 

 chloride, and the two heaviest applications of mercurous chloride and of 

 Semesan Jr. The 2-gram applications of Bayer dust and of Dipdust were, 

 on the other hand, rather ineffective in controlling the disease. Of the 

 remaining treatments, those with the two heaviest applications of aluminum 

 sulfate, the 4-gram application of Bayer dust, and the 4- and 6-gram 

 applications of Dipdust, gave the least satisfactory results (Plate V, 2). 



No evidence of chemical injury was noted except in a few of the plats 

 receiving treatments 11, 12, 14, 15, and 18, where there was an indication 



