New York Agricultural Experiment Station. 2dS 



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 the others, some of them being injured by 

 the weakest emulsion, half of those treated with tlie 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 even 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 uninjurc d 

 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. 



