CONTROL OF Two ELM-TREE PESTS 



509 



dead branches and were in a weak, dying condition, 

 sprayed thor- 

 oughly with 

 " Black-leaf" 

 tobacco ex- 

 tract, 3 gallons 

 to 200 gallons 

 of water, with 

 10 pounds of 

 fish-oil soap 

 and 8 pounds 

 of arsenate of 

 lead. "Black- 

 leaf " tobacco 

 extract con- 

 tains only 2.7 

 per cent nico- 

 tine and is 

 usually diluted 

 at the rate of 



These trees were 



FIG. 178. Unsprayed leaves infested with the miner 

 i gallon to 70 or 80 gallons of water. 



In these experiments the mixture 

 was slightly 

 stronger than this, 

 because of the 

 necessity of 

 thorough work. 



Owing to diffi- 

 culty with the pump 

 and the engine 

 there was a delay 

 of a day or two in 

 getting to these 

 trees, and some of 

 the larger larvae 

 were not killed so 

 soon as had been 

 expected. The 

 tobacco must have 

 worked o n them 

 FIG. 1 79. Sprayed leaves from the same tree slowly, however, 



for the trees made 

 better growth than they had before in some years, and looked in the fall 



