194 DESTRUCTIVE INSECTS. 



This is a very important factor in the success of the " digging 

 out" method. Dig out the borers in June or in June and 

 September in northern peach-growing districts. 



We kept out about two-thirds of the borers with tobacco 

 stems wound around the tree just below the surface of the 

 soil. The old " mounding " method evidently has considerable 

 value as a preventive, and is, perhaps, the cheapest method 

 yet devised. It is the most practicable method yet suggested 

 for combating the insects in nurseries. Paper protectors, 

 when carefully put on and kept intact during the danger 

 period, will prove a valuable and very cheap preventive 

 measure, especially when combined with the " digging out" 

 method. Wooden boxes or wire cages did not prevent the 

 entrance of the borer. 



The favorite method of preventing the ravages of the peach- 

 tree borer has been, for at least a century, by the use of a 

 wash of some kind. More than fifty different washes have 

 been concocted, most of which are valueless as preventives, 

 and some of which will injure or kill the trees. Soap, lime, 

 or clay proved useless ingredients of washes in New York's 

 climate. Paris green did not add to the effectiveness of a 

 wash, and is a dangerous ingredient to use on a tree. Car- 

 bolic acid or other odorous substances did not repel the in- 

 sect. 



Gas tar proved to be the best application we tested. We 

 used it freely on the same trees for three successive years 

 without the slightest injury to the trees, and it kept out nearly 

 all the borers. Go slow with it, by first testing it on a few 

 trees in your orchard, as trees have been killed with it. 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. 



The following substances injured or killed our young trees, 

 and are, therefore, classed as dangerous: Paris green and glue, 

 raupenleim, dendrolene, white paint (with or without Paris 

 green), and printer's ink. 



The following is a list of the things we found to be practi- 

 cally ineffectual or useless : Wire-cages, carbon bisulphide, 

 asafoetida and aloes, lime, salt and sulphur, resin wa^h, hard 



