New York AGRICULTURAL EXPERIMENT STATION. aud 
SUMMARY FOR ORCHARD I. 
In the winter treatment (Table I) none of the healthy plum 
trees showed evidence of injury by the 25 per ct. emulsion but 
all were injured and some killed by the 40 per ct. and above. 
In all cases the old trees (Reine Claude) were more sensitive to 
the treatment than thé others, some of them being injured by 
the weakest emulsion, half of those treated with the 4 per ct. 
seriously injured and all killed or seriously injured by the 
stronger emulsion and the undiluted petroleum. The younger 
trees, Monarch and Quackenboss, especially the latter, stood the 
treatment better, being uninjured by the 25 per ct. and only 
slightly by the 40 per ct. emulsion. The pears and cherries were 
uninjured. 
The spring treatment (Table II) shows ¢ven more serious 
injury to the Reine Claudes than the winter treatment but the 
other varieties consisting of younger trees were less affected 
being uninjured by the 40 per ct. and only slightly by the 60 
per ct. emulsion. Both the pears and cherries were uninjured 
by the highest percentage of petroleum (60 per ct.) used in this 
series. 
As was to be expected the winter and spring treatments com- 
bined (Table III) caused more serious injury than either of the 
single applications. The Quackenboss was the only variety 
treated with 25 per ct. emulsion and the trees were not in: 
jured. Reine Claudes and Monarchs were treated with the 
higher percentages with the result that every tree was killed. 
From these results it appears that the spring treatment was 
Slightly less injurious than the winter treatment while the two 
combined proved fatal except with the 25 per ct. emulsion, 
The 40 per ct. and stronger emulsions caused so much injury 
to the plum trees as to indicate that they are dangerous. The 
only exception was the Quackenboss trees which were uninjured 
by the 40 per ct. although unable to withstand the higher 
percentages. The lack of injury to the pear and cherry trees 
even by the undiluted petroleum indicates strongly that these 
trees are much less susceptible to crude petroleum than the 
plums. 
