103 



case eleven forest trees in a group were infected, the original 

 infection having been two trees, dating apparently from as early 

 as 1007. Up to tlie present time (June, 1011) the disease has not 

 reappeared at any point where eliminated and the country with- 

 in a radius of approximately thirty-rive miles from Washington 

 is apparently free from the bark disaese, although new infections 

 must be looked for as long as tho disease remains elsewhere 

 unchecked. It is therefore believed that this method of attack 

 will prove equally practicable in other localities, and if carried 

 out on a large scale will result ultimately in the control of the 

 bark disease." 



Since June, two new points of infection, dating probably from 

 1910, and a third suspicious point have been discovered within 

 this area. This was exj^ected, as above. If the results of legis- 

 lation this winter show that an effort will be made to control the 

 disease in Maryland, Virginia, and the District of Columbia, 

 these points of infection and any others that may be found will 

 be destroyed in the spring. Otherwise the experiment will «be 

 abandoned, except for keeping a record of previous cuttings. 



Since Christmas six of the fourteen points above referred to 

 have been visited. In one case where only diseased limbs were 

 removed and the balance of the tree left standing, the tree has 

 become infected. This was expected; we have always recom- 

 mended complete destruction of diseased trees. At two points 

 the diseased trees were cut, but the stumps left unbarked. This 

 we believe to be bad practice, but in spite of this the stumps are 

 still with one exception unaffected. In the other three cases 

 the trees were entirely destroyed, and the disease has not reap- 

 peared in the vicinity. The regular inspection of all fourteen 

 points will be made again in May and June, after the leaves are 

 out, as has been our previous practice. 



Only indicative conclusions can be drawn from the above ex- 

 periment until at least six more years have passed. It should be 

 borne in mind that this is an experiment, not a demonstration. 

 The experiment should in any case have been duplicated in var- 

 ious parts of the country. It is not too late to do this now; even 

 in States where it is too late to attempt general control, local 



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