NEW YORK EXPERIMENT STATION BULLETIN 377 



J. B. Smith* recommends a fish oil soap which can be made after the 

 following formula: 



Concentrated lye 3^ pounds 



Water 7-^ gallons 



Fish oil 1 gallon 



The l3'e should be dissolved in boiling water and the fish oil at once 

 added. This mixture should be kept boiling for two hours and then 

 allowed to cool. This soap should be used at a strength of one pound 

 to one gallon of water. 



Pure kerosene oil has been used as a winter application with varying 

 degrees of success. It will kill all the scales with which it comes in 

 contact, but unless the tree is very hardy or the conditions are just 

 right it is liable to kill the tree also. It should not be used except in 

 extreme cases. 



When the trees or nursery stock are to be fumigated with hydrocyanic 

 acid gas, the gas may be generated after the following formula: 



Fused cj^anide of potassium [98 per cent] 1 oz. 



Sulphuric acid, commercial 1 oz. 



Water 3 ozs. 



Pour the water and the sulphuric acid into a glass or glazed earthen- 

 ware dish. When this is placed where it is to remain add the cyanide 

 of potassium. This will generate enough gas for 150 cubic feet of space. 

 Much care should be taken that the operator does not breathe any of 

 the fumes. 



Fumigation is not considered the most practical method of treatment 

 for infested orchard trees here in the east, but it may be used for infested 

 nursery stock. On another page reference is made to treating nursery 

 s'tock in large cellars. A convenient house for fumigating a small 

 amount of nursery stock is shown at Plate IV. These may be built any 

 convenient size. Thej' are built of a double thickness of boards with 

 building paper between to make them as nearly air tight as can be con- 

 veniently done. The door is made to fit very tight. The stock is piled 

 in the house in such a manner as to allow the gas to circulate freely. 

 One generator with enough material to fill the space is placed about the 

 middle of the floor, and as soon as the cyanide is added, the door is 

 shut and the stock left for an hour. When the fumigating is done on a 

 cool, cloudy day, or at night, there is practically no danger of injuring 

 the stock as shown by the fact that various varieties of fruit trees, also 

 currants and gooseberries, have been exposed in the building shown in 

 the plate and in others in their immediate vicinity, all night without 

 the least apparent injury. 



A closely allied species common in New York. — This insect Aspidiotiis 

 ancylus Putn., resembles the San Josd scale in general appearance and 

 is frequently mistaken for it. It is not a serious pest in this state, how- 

 ever, but in the south it may occur in sufficient numbers to do serious 

 injury to the infested plants. Its life history has not been worked out for 

 this locality. 



*N. J. Agr. Exp. Stas. Rept. 1896, p. 559. 

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