612 Report of Entomologists of the 



placed under the box. As soon as the potassium cyanide is dropped 

 into the generator the hole under the box should be closed with a 

 short piece of board and banked with dirt. It is best to run the 

 generators during cloudy days, or during early morning and 

 late in the afternoon. The gas should be allowed to act for one 

 hour. 



Dipping Stock. — As Parsons & Sons JS'ursery Co., follow the 

 plan practiced by some nurserymen of digging their stock only as 

 needed to fill orders, some plan, which would be as cheap and more 

 convenient for small lots of trees than the gas treatment, had to be 

 devised. Dipping the trees in a solution of whale-oil soap appeared 

 feasible and harmless to the trees. For this purpose the tank shown 

 at Plate II, was made. This nursery haul their stock to one 

 packing house to pack, hence it was an easy matter to dip the stock 

 before packing and the principal cost by this method of treatment 

 was the tank and soap. The tank was made of galvanized iron and 

 cost $9.00. It is approximately 8x2x1 feet, and will hold a trifle 

 over 94 gallons. It was found more convenient to only use from 

 60 to TO gallons of ihe mixture at a time. Whale oil soap costs 6|- 

 cents per pound in half barrel (200 lb.) quantities in NewYork city. 



C. L. Marlett * in his report on " Experiments with winter washes 

 against the San Jose scale " says : " Wliale-oil soap washes, even at 

 tbree pounds to the gallon are thin enough when cool to be sprayed 

 without difiiculty and no trouble whatever was experienced with 

 one and one-half and two pounds to the gallon." 



There must be a difference in the whale-oil soap manufactured by 

 different firms. It was found that two pounds of the soap, obtained 

 in INew York city, added to a gallon of water had to be kept at a 

 temperature of about eighty degrees to work well, and, if allowed 

 to cool below sixty degrees it formed a very thick soft soap. It had 

 to be scooped out of the tank into a kettle each morning and 

 remelted, after which it was kept warm by placing an ordinary oil 

 stove under the tank. 



Parsons & Sons Nursery Company have only used this tank since 

 !November 10th, and none of the treated stock has been inspected. 

 From the tests made of whale oil soap by the United States Division 

 of Entomology near Riverside, Maryland; also, from those made 

 during the fall in the nursery of Keene & Foulk at Flushing, it is 



* Insect Life, Vol. VII, p. 3G8. 



