Plot IX-S has been in operation for 5 years and the data for the check, 
pruning, and Koloform sprayed blocks cover the entire period. Pruning in addition 
_ to Koloform has been done for 2 years only.- The most prevalent elm disease in this 
| plot is the Coniothyrium canker, Pruning during 5 years proved about 25 percent 
effective and Koloform spray about 35 percent effective. The pruning of a group of 
the sprayed trees during the past 2 years has not materially affected the value of 
| the spraye 
Plot XIV, in progress for 2 years, provides a test of the effectiveness 
of sulphur dusts in the control chiefly of Phoma dieback. Neither flotation sulphur 
dust nor Kolodust give noteworthy control, but pruning appears to have been about 
40 percent effective, With pruning and flotation sulphur combined a large increase 
over the effectiveness of each appears demonstrated in nearly 65 percent control. 
But with Kolodust and pruning combined, the 25 percent cmtrol obtained is less than 
that shown for pruning alone. 
Two-year Tests of Dormant and Summer Sulphur Sprays 
The possibility of increasing the effectiveness of sulphur sprays by 
supplementing them with dormant season sprays has been under test for 2 years. In 
plot XII, consisting of 850 trees, combinations of liquid lime sulphur as the dormant 
, spray and dry wettable flotation sulphur and Koloform as summer sprays have given 
| the data shown in table 3, 
| Outstanding is the fact that the addition of lime sulphur as a dormant 
| spray has not tended to increase the effectiveness of summer sulphur sprays, and in 
this plot it is important to note that pruning, whether used alone or in combination 
| with sprays, has tended very decidedly to increase the proportion of diseased trees, 
-Qea 
Pia. ee 
