Entomological Division. 431 



believed tliat the distribution of the root forms is thus facilitated 

 by the ants, and they may also aid in getting the aphids to the 

 surface in the spring. The aphids repay the ants for their assist- 

 ance by secreting a sweet liquid called honey-dew, upon which 

 the ants feed. 



The root forms mostly congregate on the tendtuvst ro«»ts, but 

 some are to be found on all parts of the root system. Many of 

 them still cling to the roots when the trees are dug np, ; U(3 they 

 are thus often transported great distances on nursery stock. 

 The pest then readily acclimates itself to its new homo and &oon 

 spreads throughout whole nurseries or orchards. 



Above ground the insects attack the swelling buds in the 

 spring, and later their increase in numbers crowd them onto the 

 twigs and leaves. As each little aphis begins to suck the sap as 

 soon as it leaves the body of the mother, the result of so many 

 hiindreds of those little pumps working almost continuously upon 

 both roots and branches must be a speedy check to the growth of 

 the tree. 



Methc)ds of preventing the ravages and spread of this pest. — If 

 this jiest on.ce gets a good foothold in a nursery or young orcharil 

 it will prove a difficult insect to fight. Those individnals that 

 infest the branches are easily reached and have been found to suc- 

 cumb readily to either kerosene emulsion or a strong decoction of 

 tobacco.* The emulsion should be diluted with nine or ten parts 



*To make the emulsion, thoroughly dissolve one-half pound hard or soft soap 

 in one gallon boiling water. While this solution is still very hot, add two gallons 

 kerosene and quickly begin to agitate the whole mass through a syringe or force 

 pump, drawing the liquid into the pump, and forcing it back into the dish. 

 Continue this for five minutes or until the whole mass assumes a creamy color 

 and consistency wliich will adhere to the sides of the vessel, and not gUde off 

 like oil. It may now be readily diluted with cold rain water, or the whole 

 mass be allowed to cool when it has a semi-soHd form, not unUke 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 emulsion, it is necessary to dissolve the 

 amount required in three or four parts of boiling water, after which cold rain 

 water may be added in the required quantities. 



The tobacco decoction is made by steeping five pounds of tobacco stems in three 

 gallonsof water for three hours; then strain and dilute with enougli water to 

 make seven gallons. The decoction is now ready for spraying without further 

 dilution. 



