The Peach-Tree Boeer. 241 



used it freely on the same trees for three successive years without 

 the sHghtest injury to the trees and it kept out nearly all the borers. 

 We had been led to believe that tar was very injurious to young 

 trees, and confidently expected to see our trees die each year after 

 being treated with it. But the trees kept just as healthy and grew 

 as thriftily as any others in the orchard. Let the trees become thor- 

 oughly established and get a year's growth, and it is our experience 

 that tar can be used with safety on them. Go slow with it, by first 

 testing it on a few trees in your orchard. We believe it will prove 

 equally effective whether the borers are dug out or not, and from 

 no other application yet devised would we expect to get such results 

 when used independent of the "digging-out" method. 



A few miscellaneous washes of very doubtful value are discussed 

 on p. 236. 



Some general conclusions regarding washes. — Lime and some 

 kind of soap are often the principal ingredients of washes. Our 

 experience leadr us to believe that neither of these substances exer- 

 cise any preventive effect on the peach-tree borer. Furthermore, 

 climatic conditions in New York and doubtless in most northern 

 peach districts, will cause any wash containing much lime to scale 

 off and thus render it ineffective, before the moths have stopped 

 laying eggs. Tlius soap and lirne or clay are useless ingredients 

 and lime may seriously interfere with the effectiveness of a wash in 

 moist climates. 



We do not believe a poison like Paris green adds anything to the 

 effectiveness of a wash, and it may prove a dangerous ingredient, as 

 with glue or white paint. The theory upon which the poison is sup- 

 posed to work is a wrong one. The newly-hatched borer does not 

 deliberately eat its way through the wash and thus get some of the 

 poison, according to the theory, but it seeks a minute crack or crevice 

 and works its way in below the surface bark, on which the wash is 

 applied, before it begins to eat. We believe this last fact, regarding 

 the entrance of the newly-hatched borer into the tree, will explain 

 much of the ineffectiveness of washes. It is very difficult to so 

 thoroughly cover the bark of even a young peach tree that many 

 minute cracks will not be left or soon be made through the wash by 

 climatic conditions or by the growth of the tree. 

 16 



