THE MONTHLY BULLETIN. 559 



was everywhere in evidence. A peculiar fact noted by Mr. Fiske, 

 with regard to this disease, is that strangely enough its virulence is 

 greatly augmented when the caterpillars feed upon certain species of 

 trees and shrubs, and for that reason these trees are practically resistant 

 to the gypsy moth attack. The great importance attached to this dis- 

 covery is obvious. 



Mr. Fiske has spent a large part of the past four years abroad in the 

 study of the gypsy moth, paying especial attention to its control 

 through natural factors. He also investigated carefully the effect upon 

 the moth's abundance of certain types of forests and forest manage- 

 ment. His study in Europe, added to by extensive experiments carried 

 on in this country under the direction of A. F. Burgess of the United 

 States Department of Agriculture and Doctor Wheeler of Harvard, 

 has thrown great light upon the subject of resistance of various types 

 of forests to the moth through the agency of the ' ' wilt. 



Jn brief it has been found that upon certain trees, principally the 

 oaks and birches, the moth increases rapidly to the point of complete 

 defoliation. Upon certain other trees, when growing alone, it rarely 

 increases to the point of defoliation, and usually is barely able to hold 

 its own. This latter group includes the conifers, some poplars, chest- 

 nut, hickory, sycamore, elm, catalpa, ash, locust, maple and several 

 others. These trees are spoken of as being resistant to the gypsy 

 moth through the operations of the "wilt" disease. 



With regard to the practical application of this valuable informa- 

 tion, Mr. Fiske has the following to say: 



"There are, therefore, two phases of the complex problem of gypsy 

 moth control in forests which must be considered. First, how best to 

 eliminate the oak and secure its replacement by other, and, if possible, 

 more valuable trees; and, second, how best to protect the oak from 

 serious injury in localities where little else can be grown to advantage. 



" In a large portion of the area at present infested by the gypsy moth 

 the solution is almost absurdly simple. This is the natural home of the 

 white pine, one of the most valuable timber trees to be found in the 

 whole' temperate zone. In a way the oak is an interloper. Over a 

 large part of New England the white pine was once preeminent, and 

 it Avould become so again were the country to be deserted by civilized 

 man. The pine reproduces freely, if given half a chance, but there are 

 thousands of acres in the aggregate in which a natural reproduction of 

 pine is being retarded, destroyed even, through the mere circumstance 

 that the oak chanced to secure a running start, by sprouting when the 

 land was last cut over. The German forester who would permit such 

 conditions to prevail would be considered hopelessly, even criminally, 

 insane. Under such circumstances oak is to be^considered a?, a weed, 

 and the advent of the gypsy moth as a blessing when, as sometimes 

 happens, it takes the oak and leaves the pine. If it would always do 

 just that and nothing more its progress might be watched with a 

 certain degree of complacency. But it does not always stop at that, 

 and, what is worse, injudicious cutting not infrequently results in 

 greater damage than would be done by the gypsy moth itself. The 

 larger pines are apt to be cut or broken down, and the smaller ones, 

 unable to compete with the rapidly growing oak sprouts, are quickly 

 in no better condition than before. 



