42 James Stewart Wiant 



of very slight stunting. This injury is of no particular significance except 

 to indicate the maximum amount of these chemicals which can safely be 

 employed under these conditions. 



Norway spruce — Liquid treatments. Solutions of mercuric chloride 

 and several organic mercury materials were used on spring-sown beds of 

 norway spruce during the season of 1926. The details of the experiment 

 are recorded in table 12. The low figures for percentage of emergence in 

 both the treated and the untreated plats are due in part to the low viability 

 of the seed and in part to the fact that the seeds were sown at a greater 

 depth than usual. Damping-off, which occurred chiefly in the check plats, 

 was rather unevenly distributed. The heavy losses noted from treatments 

 2, 8, 10, and 12 were due primarily to the injurious effects of the second 

 application of chemical. Although the losses with the other treatments 

 were considerably lower than those of the check, significant differences 

 occurred only with treatments 1, 3, 6, 13, 15, 17, 21, and 23. Similarly, 

 for the final stand significant differences were found only with treatments 

 11, 15, and 23. 



Second applications of mercuric chloride and of the stronger treatment 

 with Bayer compound caused marked injury. This was manifested by a 

 killing of some seedlings and a severe stunting of others. The larger 

 amounts of the other chemicals caused slight retardation, while with the 

 smaller amounts slight stunting was noted in several of the replicates. 

 With the single-application treatments, retardation was noted in several 

 plats where the larger amounts were used. Observations were again 

 made at the end of the second growing season. Although considerable 

 variation in the size of the seedlings occurred, it was possible to group the 

 plats in. a general way. In the plats of class A, therefore, most of the seed- 

 lings were typical of the average stock commonly used for transplanting. 

 In those of class B the stock was of a somewhat smaller size than in A. but 

 large numbers of these seedlings would normally be transplanted. In 

 those of class C the majority of the seedlings were of decidedly inferior 

 quality and would be discarded. 



This experiment indicates that norway spruce is rather susceptible to 

 chemical injury, and that of the treatments employed only the single 

 applications with the smaller amounts are practicable for use on this species 

 under these conditions. 



Liquid treatments were used also in one series of norway-spruce plats 

 sown in the fall of 1926. So little damping-off occurred that counts were 

 made only of the final stand. From table 13 it is seen that stunting 

 occurred from a number of the treatments. Since germination did not 

 take place until the spring of 1927, five months after the time of treating, 

 it would appear that either the chemicals exerted a toxic action upon the 

 dormant seed, or else they were present in a readily available state at the 

 time of germination. The latter hypothesis seems the more tenable. 



