THE POPLAR AND WILLOW BORER 475 



Experiments in 1915-16 



The success of the preliminary experiments led to the trial of the car- 

 bolineum treatment on a commercial scale. In the fall of 1915 arrange- 

 ments were made to treat two entire blocks of poplar trees in each of two 

 large nurseries. This was made possible by the courtesy of the owners, 

 who provided all the material, help, and necessary equipment, the writer 



FlG. 126. INFESTATIONS BELOW LINE OF CARBOLINEUM 



TREATMENT 

 End of treatment shown by arrow A 



taking charge of the work. Each block contained approximately fourteen 

 thousand trees. Owing to the excessive snowfall during the winter of 

 1915-16 it was not possible to apply the carbolineum as early as was 

 intended. The application was further delayed somewhat in order that 

 the trees should be pruned. 



On April 8, 1916, twenty-one rows in one block were treated. As the 

 day was cold, threatening snow and sleet, the work was discontinued. 

 During the following day over three inches of snow fell, and the remainder 



