180 THE APPLE 



Badly infested trees should be given two applications. Pruning 

 should always precede winter spraying. 



The prepared solution, in a proportion of i\ gallons of lime 

 and - sulphur to 50 gallons of water, is a dependable spray to use 

 in the summer. Although too weak to kill the protected scale 

 insects, it is caustic enough to kill by contact all that are crawling 

 or otherwise unprotected. 



The type of nozzle best adapted for use in this spraying is one 

 that throws a medium-fine, cone-shaped spray. High pressure 

 should be maintained, so that the mist at close range will possess 

 a penetrating power. 



Woolly aphis (Schizoneura lanigera, Hauss). The woolly aphis 

 works injury both to limbs and to trunks, and also to the roots. 

 It is only the injury to the roots, however, that demands specially- 

 directed treatment, the limbs and trunks being readily freed from 

 this pest by high-pressure applications of diluted lime and sulphur 

 during the summer. The white cottony substances secreted by 

 the insect protect it against contact sprays, unless administered 

 forcefully. 



The root form of the woolly aphis, by reason of its peculiar 

 feeding habits, damages the roots seriously, and not infrequently 

 causes the death of the trees. 



Treatment. The most dependable remedy yet discovered for 

 the root form of the woolly aphis is kerosene emulsion. In rec- 

 ommending it, however, an emphatic warning should be given : 

 the utmost care must be taken thoroughly to emulsify the kerosene, 

 so that it will not separate into a free state. This cannot be done 

 by merely stirring the constituents together. They should be 

 mixed in a vessel larger than necessary to hold them, to allow for 

 the increase in bulk which results from the process of emulsiTying, 

 and then be forcefully and continuously beaten for at least ten 

 minutes. A 10-per-cent solution is recommended on account of 

 the possible injury to the trees from an emulsion carrying a greater 

 percentage of kerosene, and it is as effective as a stronger solution, 

 although the length of time it retains its strength is not so lasting. 

 If the preparation is made, carefully following suggestion here 

 given, and applied only in the growing season, no damage to the 

 tree or its roots need be feared. 



