148 (iVPSY AND BROWN-TAIL MOTHS. [Jan. 



Cementing. 



Had all the trees in the infested region, particularly those in 

 orchards, been properly trimmed, it would be unnecessary to 

 speak of cementing operations. But unfortunately much of the 

 little trimming of orchards that has been done has been done 

 poorly, and as a result the majority of trees throughout the 

 district are full of cavities which would not have developed had 

 the branches been correctly removed and the wounds properly 

 treated. In preparing such orchards for exterminative work 

 against the gypsy moth it is necessary to eliminate as far as 

 possible all hiding places of the insect. To this end, therefore, 

 much closing of cavities by cementing or otherwise is required 

 in the case of trees which are to be preserved. Generally speak- 

 ing, the use of cement is preferable to other methods, because 

 of the ease with which it is applied, its economy and its adapta- 

 bility to a wide variety of conditions. 



In cementing cavities it is necessary first to remove as much 

 as possible of the decayed wood, so as to get a sound surface 

 on which to work. Next, all large cavities should be packed 

 full of stones pounded tightly together, so that the cement plug 

 shall not fall inward, and thus afford egress for any insects 

 confined within or ingress to those without. The orifice of the 

 cavity should be cut away on a bevel inward, so that its interior 

 diameter shall be greater than that of the outer edge. Then 

 the cement should be thoroughly worked in and brought flush 

 with the cambium layer of the tree, being depressed on the 

 average about one-fourth of an inch from the outer surface 

 of the bark. If these directions are followed, the cement cap 

 can never fall outward, and a natural growth of the tree will 

 hold it more tightly in place from year to year until the wound 

 i- fully closed. (See Plate, Fig. 7.) 



Tinning, etc. 



In treating orchard and other trees, cavities are often found 

 which will not permit of cementing, and these may be closed 

 1>\ tinning, or in some cases by the use of heavy burlap. In 

 tinning cavities it is desirable to cut back into the sound wood 



