24-8 Agkicultdbal Expebimknt Station, Ithaca, N. Y. 



year's growth; so it is only nec^ssarv' to cut back tha^e shoots, 

 as many growers do, and bum them, to destroy large numbers of 

 eggs. 



After the unsuccessftil efforts to destroy the eggs with insecti- 

 cides, we could do nothing more until the njTiiphs appeared'. Some 

 of the nymphs appeared before the buds had opened much; these 

 nymphs immediately^ crawled into the buds out of the reach of the 

 insecticides. It was feared that all the young and tender" nymphs 

 would thus get out of reach. But a majority of the eggs did not 

 hatch this year until many of the leaves had expanded, thus leaA'- 

 ing the nymphs exposed. During a warm early spring the eggs 

 might hatch early, but many of the leaves expand in a few days 

 and thus the nymphs would be exposed before they had become 

 more than one-third grown. 



Our experiments against the 3'oung nymphs were first carried 

 on in the insectary upon infested branches brought in from the 

 field. It was soon found that the young nymphs wei-e very ten- 

 der and very susceptible to kerosene. A kerosene emulsion was 

 prepared according to the Hubbard-Riley fonnula.* The nymphs 

 wei'e dipped in the emidsiou diluted with different quantities of 



*The formula is one-half pound hard or soft soap, one gallon water, two gallons 

 kerosene. 



First, thoroughly dis.^olve the soap in boiling water. Wliile this solution is 

 still very hot add the kerosene; if the whole is then left over the fire for a few 

 moments to raise the temperature of the kerosene slightly, it will facilitate the 

 emulsifying process. Remove from the fire and quickly begin to agitate the 

 whole mass through a syringe or force pump of some kind; draw the Hquid into 

 the pump and force it back into the dish. Continue this operation for five 

 minutes or until the whole mass assumes a creamy color and consistency which 

 will adhere to the sides of the vessel, and not glide off like oil. If desired for 

 use immediately, it may now be readily diluted with cold water, preferably 

 witli rain water. Or the whole mass may be allowed to cool when it has a 

 semi-solid form, not unlike loppered milk. This stock if covered and placed 

 in a cool dark place will keep for a long time. In making a dilution from this 

 cold stock emulsion, it is necessary to measure out the amount of the emulsion 

 required and first dissolve it in three or four parts of boiling water; if cold 

 water be used a large quantity of a white floccu!ent mass rises to the surface 

 and does not dissolve. After the stock emulsion is dissolved, cold water may 

 be added in the required quantities. If all the utensils are clean, and the direc- 

 tions followed closely, no free oil will rise to the surface of the dilution. 



