76 SOME INSECTS INJURIOUS TO FOKESTS. 



Control of the Black Hills beetle.— An extensive outbreak of the 

 Black Hills beetle {Dendroctonus ponderosce Hopk.) in the vicinity 

 of Colorado Springs, Colo., in 1905-6, which was threatening the 

 living pine timber of the entire section,, was brought under control 

 through the efforts of the private owners of forests and those of for- 

 est o%ials in the adjoining National Forests. It was accomplished 

 by cutting and barking about 1,000 beetle-infested and beetle-killed 

 pine trees. The cost of the operations was largely, if not entirely, 

 covered by the utilized felled timber, although there was consider- 

 able unnecessary expense involved through the felling and barking 

 of trees from which the beetles had emerged and from the unnec- 

 essary burning of the bark and tops. 



The successful control of another serious outbreak of the Black 

 Hills beetle, in 1906, on an extensive private estate in southern Colo- 

 rado, was effected through the efforts of the owners, who had some 

 500 infested trees felled and barked within the necessary period to 

 destroy the broods. A large percentage, but not all, of the infested 

 timber was thus treated. These operations were so successful that not 

 a single infested and dying tree could be found when the area was 

 inspected in 1908. In this, as in the other case, considerable unnec- 

 essary expense was involved in the burning of the bark and tops, 

 but the value of utilizable timber was evidently more than enough 

 to pay all expenses. It is evident that in this case a destructive inva- 

 sion was prevented. 



The most striking example of success relates to a large estate near 

 Idaho Springs, Colo., and in the adjoining Pike National Forest. In 

 May, 1907, it was found that some 63,000 feet of standing timber 

 on the estate was infested by the Black Hills beetle, and the owner 

 was advised by the Bureau of Entomology that unless the ravages 

 were checked at once the beetle would kill the timber not only on 

 this estate but that on the adjoining estates and National Forest, and 

 that therefore radical action should be taken according to the rec- 

 ommendations and detailed instructions given relating to a necessary 

 control policy. No action was taken, however, before the first of 

 the following July, and therefore not in time to prevent the broods 

 of beetles from swarming from the infested trees and extending 

 their ravages. In December, 1907, another examination of the 

 timber was made, and it was found that instead of 65,000 feet of 

 timber in the old infestation there was nearly four times as much 

 timber involved in the new, or over 250,000 feet. The owner was 

 again notified of the serious character of the outbreak, and further 

 suggestion made that if the logs from the infested trees were con- 

 verted into lumber and the slabs burned before May, 1908, it would 

 result in the protection of the remaining living timber. Immediate 

 steps were then taken by the owners to carry out the original 



