298 INSECTS 



protected. The round-headed borers of pomaceous 

 fruits like apple and quince, and the boring caterpillars 

 infesting peach and its allies, usually enter near the 

 surface and work in just at or below the ground. A 

 wash of hydraulic cement mixed with water, or better, 

 with milk, is often used to protect trees at this point 

 and on peach trees a band of newspaper or tar paper is 

 tied so as to extend a little below the surface and for a 

 distance of eighteen inches above. Other mixtures have 

 been recommended and all are more or less effective. 

 It means simply coating the bark with anything that 

 the insects cannot or will not penetrate in their efforts 

 to get to their place of feeding. 



Gas tar is safely used in some localities as a protec- 

 tion, but in others is fatal to the trees, and it is better 

 not to use tar paper or any black paper, since that 

 seems to cause a scalding of the bark beneath it. So, 

 while paints mixed with linseed oil are tolerably safe, 

 those in which turpentine is used should be avoided, 

 as they are almost always dangerous. 



A great variety of protective devices are in use on 

 trees to prevent insects from getting up or down the 

 trunk, or to attract them as shelter for larvae and 

 pupse, and some of these are effective in special cases, 

 as when a band of fluffy cotton or of a sticky material 

 bars the ascent of female canker-worm moths or the 

 ascent of caterpillars of the tussock moths, from egg 

 masses laid below them. The larvae of codling moths 

 can be attracted to burlap bands when they leave the 

 fruits to pupate, and many of them can be there gathered 

 and destroyed. Finally, on field crops we can use, very 

 effectively, tar paper discs to protect cabbage plants 

 from root maggots. 



The direct campaign with poisons is a most impor- 

 tant feature of the war with insects, and to carry it on 



