8 



been seen to fly, nor were any of them caught at trap lanterns set 

 in nursery blocks where they were numerous. Many marked 

 beetles were liberated within fifty yards of a block of poplar trees 

 but none of them were ever found on the trees. 



It seems convincingly proven that any successful treatment of 

 a nursery block of trees need not be repeated because of the 

 migration of beetles from neighboring blocks that are one hundred 

 yards or more distant. 



The Station would accordingly recommend, ex- 

 Summarized perimentally, the treatment of poplar and willow 

 directions for trees, in nurseries in localities where the beetles 

 treatment, are abundant, with a poison spray. The poison 



should be combined with bordeaux mixture, as 







such a combination will protect the trees against many fungus 

 diseases and various other insects. An application of such 

 a mixture of bordeaux with 3 pounds of arsenate of lead to 

 each 50 gallons can be made on nursery blocks of two-year- 

 old poplars at an expense of one-fourth of a cent a tree. 

 The application should be made about July 15, since the 

 beetles are most numerous after that time. As further remedial 

 measures, new blocks of poplar and willow should be set at some 

 considerable distance, say one hundred yards, away from blocks 

 of older trees. Nurserymen should, as far as practicable, dispose 

 of stock before it is three years old, as the infestation is liable to 

 gain very rapidly in the second and third years. Badly injured 

 or unsalable trees and brush left from pruning should be removed 

 and burned, as should also any infested willows along creeks, 

 ditches or swampy places near the nurseries, as these make excel- 

 lent breeding grounds for the pest. 



When a few trees or a plantation is slightly infested, the infested 

 trees or branches should be removed and burned in June, before 

 the beetles emerge. 



If willows or poplars planted for windbreaks, or screens, or 

 holders of the soil, should become so badly injured as to impair 

 their beauty, it is advisable to dig out and burn the infested trees 

 during the winter or spring, and to replant with some other kind 

 of a tree. The silver maple and Weir's cut-leaved maple are 

 recommended for this purpose, as they are said to grow well in 

 damp localities. 



