the amount of disease, and the general effect of combined pruning and spraying is a 
decrease in the effectiveness of pruning which tends to balance the ineffectiveness 
of sprays. Dusting with sulphur is, however, somewhat effective and, when combined 
‘with pruning, proves the most effective among the treatments tested. 
Tests with Sulphur Summer Spray and Dusts 
Data in addition to those obtained from the uniform 5-year long treat- 
‘ments just described are furnished by plots IX-S and XIV for a sulphur spray and 2 
sulphur dusts. These are summarized in table 2. 
Table 2,.--"Wilt" control obtained from treatment of nursery elms by pruning, by 
spraying and by dusting with sulphur, and by combining pruning with 
spraying and with dusting for various periods. 
—_—S 
Difference.in Percentage of 
Plot numbers No, of trees No. of trees favor of (+) or control (+) 
and originally contracting against (-) or lack of 
treatments used present disease treatment* control (-) 
‘Plot IX-S (sprays) 
Check, 5 seasons 226 74 
Pruning, 5 seasons 250 62 + 20 + 24.4 
Koloform, 5 seasons reg EY 47 + 28 + 34,1 
Koloform, 5 seasons 
+ pruning, 2 seasons 200 44 + 27 + 32.69 
Plot XIV (dusts, 2 seasons) 
~ Check 256 84 
Pruning 218 46 + 37 + 41,1 
Flotation sulphur 205 86 + 4 + 4,4 
Flotation sulphur 
+ pruning 220 28 + 58 + 64,4 
Kolodust 255 81 + 3$ cas a 
_Kolodust + pruning 201 53 + 23 + 2566 
ee eee 
—— 
* Calculated on the basis of 250 trees per block in plot IX-S and 253 trees per 
block in plot XIV. 
= Que 
