28 THE MISTLETOE PEST IN THE SOUTHWEST. 



TKEE SURGERY AS APPLIED TO MISTLETOE INFECTION. 



Another method of treatment will have suggested itself in the 

 case of infected limbs which are too large to be advisedly cut off 

 and in cases where the trunk is infected. Since the repeated devel- 

 opment of mistletoe shoots takes place from buds formed on the 

 cortical roots and since these roots extend only in the soft bark 

 (cortex), why not cut away the bark and cortex down to the zone 

 of young wood at these infected places? If the infection is a recent 

 one or if the infected area is very small this would be a simple mat- 

 ter of applying a gouge or chisel locally, care being taken to cut far 

 enough from the point of attachment of the mistletoe to include the 

 spreading cortical roots. Thus there would result a small wound 

 from 1 to 4 inches in diameter and extending into the branch per- 

 haps one-eighth of an inch below the inner margin of the soft bark. 

 This should be treated with an antiseptic wash, as indicated later, 

 and painted with asphalt paint or coal tar or lead in oil. 



In the case of old infection where the cortical roots have spread 

 widely the removal of infected tissue could be accomplished also by 

 means of chisel and mallet, but in such cases the size of the wound 

 becomes a serious feature. In most cases of this sort it would 

 be better to combine the surgical method with the chemical treat- 

 ment and wrapping previously described. Thus with a chisel and 

 mallet cut out each shoot or bud or bit of exposed cortical root of 

 the mistletoe, making no wounds larger than the diameter of the 

 shoot or bud removed; then paint with, carbolineum and wrap with 

 burlap, or treat with an antiseptic wash and then paint with asphalt 

 paint, coal tar, or other waterproof dressing. 



In this connection a word may be said about the general sub- 

 ject of mutilation of trees and the treatment of w 7 ounds in trees. 

 It should be understood that every wound on a tree invites disease 

 from some fungous or bacterial infection. Unwise or careless prun- 

 ing or trimming of trees is a source of much ultimate and really 

 preventable damage. It is of course necessary to cause these wounds, 

 but to leave them ragged and undressed is not necessary, nor is it 

 any more rational than it would be to treat animals by the same 

 cruel system of surgery. Whenever a w 7 ound is made on a tree, 

 whether in ridding it of mistletoe or from whatever cause, it should 

 be disinfected and dressed so that no disease spores can enter while 

 the wound is healing over. The antiseptic wash may be prepared 

 by dissolving 1 part of corrosive sublimate in 1,000 parts of water; 



« For further advice in this connection, see "Pruning," Farmers' Bulletin 181, by 

 L. C. Corbett, and "Diseases of Ornamental Trees," by Haven Metcalf, in Year- 

 book, U. S. Dept. of Agriculture, for 1907. 

 166 



