johannsen: apple-tree borer control 
385 
little clay into it. Against the tree, with the open side over the borer 
holes, build a clay cell with open top, resembling a large mud-wasp’s nest. 
Have ready a flat piece of clay for a lid. The size of the cell is dependent 
upon the number of holes it has to cover. 
5. Put a small, loose wad of paper in the cavity of the clay cell, pour 
over it a teaspoonful of carbon disulphid, and clap on the lid. 
6. Quickly and firmly seal on the lid, wetting the surface of the whole 
cell, rubbing smooth with the hand, and sealing tightly to the ground and 
to the tree. If the clay or muck is of the right sort, an air tight cell is 
thus formed which communicates only with the burrows of the borers. 
If the clay cell is well constructed, the odor of the carbon disulphid is 
still apparent upon opening the cell 24 hours later. Upon investigation 
the insect will be found dead in its burrow. In my experiments I did not 
fail to kill the boreres in situ in a single instance. 
A few cautions should be observed. Use fine clay or loam such as 
will work up well into a putty-like mass and is not crumbly. Seal the 
cell carefully to the tree and to the ground, smoothing the surface with 
the hand which has been dipped in water. If the ground is porous, 
floor the cell with clay also. Follow up your work after several weeks. 
Some of the borers may not have been active when going over the orchard 
the first time and thus have been overlooked. Mark the side of the tree 
which has been treated so that later on you may know how effective your 
work has been. 
This method kills borers in the root-base as well as those in the trunk. 
A man working alone should be able to treat 50 trees a day effectively, 
which is more than can be done by the digging-out process, as figures, 
which have been kept by the Department of Pomology of Cornell 
University, show. The method is applicable to trees of any size and for 
borers of any age. It may be used at any time between May and Oc¬ 
tober. It has the advantage over “digging out” in that it requires less 
time, neither mutilates nor injures the tree, and when properly done is 
100% efficient. 
Instead of clay, plasticine may be used. It is easy to apply, takes 
less time, is much less messy, and may be used several times over. 
The only objection to it is the expense. Whether the slight amount of oil 
in its composition has any injurious effect upon the tree remains to be 
seen. Dry, finely pulverized clay mixed with about one-fifth its bulk of 
vaseline makes a fair substitute for plasticine. 
In a few cases where the borer holes were up some distance from the 
base, tar paper was used for the body of the cell and sealed to the tree 
