﻿78 SEVENTH ANNUAL REPORT 



has finally painted them with a mixture of soap, lime and a small 

 proportion of Paris Green. The Green might, I think, be dispensed 

 with, but the lime gives consistency as well as persistency to the 

 soap, and in many of the trees thus treated the larvae have actually 

 worked their way out only to fall to the ground and perish. A small 

 proportion of glue dissolved in the mixture would add etill more to 

 its persistency, and, being gradually dissolved by the rains, not injure 

 the tree. 



Other substances have been applied to trees as preventives of the 

 attacks of this insect, and right here the question is naturaly asked, 

 "does it hurt trees to grease them?" The question has been dis- 

 cussed for many years by horticultural bodies, and the individual 

 experience is always conflicting. Indeed, it only admits of a condi- 

 tional answer, as so much depends on the quality of the grease and 

 the time of year in which it is applied. All greasy substances of such 

 consistence that they will effectually preclude the air for any length 

 •of time must necessarily be injurious, whereas, if they soon evapo- 

 rate or crack open they may be applied so as to produce no injurious 

 effects. Kerosene and axle grease have been used by several promi- 

 nent Kansas fruit-growers, without injury to the tree, and with satis- 

 factory results in keeping off both borers and rabbits. Coal tar has 

 ■sdso been used for the same purposes, and with satisfaction, by many, 

 and is now being extensively tried in the college orchards at Man- 

 hattan, and by H. E. Van Deman of Geneva, and others; while pitch 

 tar applied direct to the tree is generally injurious. 



From what has already been said we see the importance of keep- 

 ing the bark smooth, whether by the use of soap or by scraping. The 

 former mode of keeping the bark smooth is altogether preferable, not 

 only because it is more obnoxious to the beetle, but because it is less 

 hurtful to the tree. For it is a fact, exemplified in the experience of 

 Mr. Wm. R. Randall, of Washtenaw county, Michigan, as communi- 

 cated to the jVe^o York Tribune, that in scraping trees or in using a 

 knife to cut off the loose bark, the fresh bark is often abraded and 

 bruised so as to form just the nidus needed by the beetle. And Mr. 

 Randall found that the very parts which he had left exposed in this 

 manner by Summer scraping were afterwards well supplied with 

 borers. Scraping, therefore — if it has to be done — should be done 

 early in Spring, before the beetle appears, so that any unavoidable 

 bruising may have time to heal before Chrysobothris is seeking to 

 deposit her eggs. 



