THE PINE INVESTIGATION. 299 



POSSIBLE METHOD OP CHECKING THE TROUBLE. 



The fact is that the trouble has now extended over an area in Virginia and 

 West Virginia of at least 10,000 square miles during the last three years, 

 killing possibly 75% of all the large pine except the white pine, making 

 the trouble appear to be beyond control, at least as far as the yellow, pitch 

 and scrub pine is concerned. 



In regard to^the spruce and white pine, they are the last to be attacked 

 by this destroying beetle, thus indicating that they are naturally more 

 capable of resisting the attack. 



Therefore, any natural or artificial means that would reduce the num- 

 bers of the beetles or prevent their increase would possibly check the 

 trouble entirely in the spruce and white pine. 



It is only through the attack of great numbers of these beetles that they 

 are capable of killing the trees, therefore, any method which would even 

 slightly reduce their numbers might be the turning point lead- 

 ing to their natural death from lack of proper conditions for their 

 multiplication. It seems necessary that they kill the trees in which 

 they breed, and, if at any time there is not enough of them to kill the trees, 

 this-will end their destructive existence. 



The only apparent way to accomplish the above end is through the 

 natural appearance or artificial introduction of some disease or insect 

 which will prey upon the destructive beetle and thus reduce its num- 

 bers. 



A species of disease has been discovered by us which is killing them to 

 some extent in the pine, but the beetle seems to have few insect enemies 

 in the country. 



SIMILAR TROUBLES CONTROLLED BY THE NATURAL APPEARANCE AND ARTIFI- 

 CIAL INTRODUCTION OF INSECTS. 



A similar trouble in the spruce between 1882 and 1889, when at least 

 10% of the 500,000 acres of spruce in the State was evidently killed by the 

 spruce bark beetle (Polygraphus rufipennis) was, I have every reason- to 

 believe, reduced beyond its destructive power by the natural appearance 

 and increase of at least six species of insects which feed upon it. 



It is a demonstrated fact that the introduction of a species of the "Lady 

 Bug" from Australia for the purpose of feeding on and destroying a de- 

 structive orange insect in California resulted in the almost total destruc- 

 tion of the orange insect and a saving of millions of dollars to the orange 

 growers of the State. 



It has therefore seemed to me very possible that if we could introduce 

 certain insects that would feed upon the destructive pine bark bee- 

 tle, a great saving might be effected at a comparative light expense. As I 

 know of no insect in this country which would likely be effectual, it oc- 

 curred to me that some foreign species known to feed on beetles similar to this 

 one if introduced might have the desired effect. Upon my return from the 

 first investigation in May, I wrote to my correspondent in Strassburg, Ger- 

 many, who is one of the best informed entomologists, and the Emperor's 

 overseer of the forest of Elsass, asking him if he would procure and send 

 me certain species which were known to be very beneficial to their forests. 

 His prompt reply which I have just received, informs me that old age and 

 poor health would prevent him from aiding me in the experiment, but re- 

 ferred me to another party in Saxony who would doubtless give me the 

 desired information and aid. 



I shall make every effort in my power to secure as many friendly insects 

 as possible from Europe, which should arrive here in time for them to be 

 introduced into the forest by the middle of August, or^first of September. 

 I shall communicate with the party mentioned, by cablegram in order 



