New York Agricultural Expeirimbnt Station. 21 



ence was probably due in large part to imperfect protection and 

 accidents to the treated buds after setting. 



Tlie experiments of Series II resulted in a failure to kill the 

 scales during the winter with gas of less strength than .3 gram 

 of cyanide. The spring treatment gave different results. The 

 gas at a little more than half the strength (.18 gram) killed the 

 scales in every case and did not injure the foliage. 



In tests made on Long Island the conclusion was reached that 

 it is possible to exterminate the scale in small, isolated orchartTs 

 of small trees by fumigation. Under favorable circumstances 

 the gas from .15 gram of cyanide per cubic foot of space sufQced 

 to kill the scales; but where the fumigation is done over damp 

 soil, or when the trees are wet, it is best to use twice this 

 amount as the gas is rapidly absorbed by water, thus reducing 

 the percentage in the air. It is safe to use gas of this strength 

 (.3 gram of cyanide per cubic foot) for frojn 30 to 60 minutes 

 upon all dormant orchard trees. 



Trials of different proportions of cyanide, acid and water in 

 the formula for generating the gas in fumigation showed that 

 1 part of lump cyanide by weight, \\ times as much acid by 

 volume and 3 times as much water by volume gave complete, 

 rapid and not too violent chemical action. This formula differs 

 but slightly from the commonly used formula (1-1^-2:^); so that 

 the latter may be followed if preferred, using a little more water 

 if the action seems too violent. 



Promising inseotioides. — Certain insecticides which were tried 

 as most promising remedies for the San Job6 scale, but which 

 require further tests to demonstrate their value are whale-oil 

 soai) and crude petroleum compound, the lime-sulphur-and-salt 

 wash and a kerosene-lime emulsion. 



Modlfloation of the Station fumigatm: — This consists of a new 

 method of holding the door in place. Instead of buttons, four 

 strips extend across the front of the door and project about 

 three inches on each side. The projecting ends are cut on a 

 bevel and fit against corresponding surfaces of blocks fastened 

 to the sides of the fumigator. As the door is pressed down it 

 is forced securely into place. 



