’ 
Table 4,=—"Wilt" control obtained from 2 years! treatment of nursery elms with 
dormant and summer copper sprays. 
ee 
——— 
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 XII 
Check 134 21 , dey 
Pruning 145 35 - 12 = 5202 
Z=0 143 28 = 5 - 21.7: 
Z-O + pruning 133 21 O 0.0 
Plot XIII 
Check 186 57 
Pruning 181 40 ~ 4 - 10.8 
Instant Bordeaux 178 54 - 19 - 51.4 
Instant Bordeaux 
+ pruning 186 29 + 12 + 3204 
*Calculated on the basis of 145 trees per block in plot XII and 186 trees per 
Block in plot, XLII. 
Results 
The Re ee and text have given detailed data derived from 
practical tests, conducted under actual nursery conditions, of a number of fungi- 
cides as preventives of “elm wilt." Other considerations, such as effect of treat- 
ment on growth, general health, survival, or value, have been ignored, A tree, 
ence it became diseased, was counted out permanently, whether eventually it lived 
or died. Consequently the information presented deals solely with the effect of 
treatment upon new infection, 
Because elm wilt" is a. collection of diseases, one of which may pre- 
dominate in one situation or in one year and another elsewhere or in another year, 
experiments have been scattered among selected tree plots located at some distance 
] from each other. This has provided opportunity for fairer tests of treatments and 
-lle 
