INSECT ENEMIES OF WESTEllN FORESTS Hg 



Some attempts have been made in California to control outbreaks 

 of this beetle in youno- pine stands by felling the trees and burning 

 the infested bark nnich as is done for the control of the western pine 

 beetle. Usually such methods are not Avarranted, as outbi'eaks are 

 sporadic and can be avoided if roadway, line, or other slash is burned 

 before the beetles emerge, or in logging operations if a continuous 

 supply of fresh material is provided to absorb developing broods. 



The Arizona five-spined engraver {Ips lecontei Sw.) is the south- 

 western form of /. confusus. It attacks ponderosa and other pines in 

 the southern Rocky Mountain region and at times is exceedingly 

 destructive. Its characteristics and habits are very similar to those 

 of its near relative, and the methods of control are the same. Re- 

 cently some rather extensive operations have been carried on in 

 Arizona to control this beetle. 



The Vancouver ips (/. vancouveri Sw.) is also closely allied in 

 character and habits to /. confusiis^ but is slightly larger. The adult 

 beetles are reddish brown to black, about one-fourth inch in length, 

 and with five spinelike teeth on the margins at each side of the 

 concave elytral declivity, which is densely clothed with long, slender 

 hairs. These beetles usually attack decadent or weakened western 

 white pine, sugar pine, foxtail pine, lodgepole pine, and Sitka spruce 

 throughout the Northwest, but under favorable conditions will attack 

 apparently healthy trees. The gallery pattern is of a radiating, 

 longitudinal type with three to five short egg galleries extending up 

 and down the tree from the nuptial cliamber. There are apparently 

 two but possibly three generations a year. 



The Cloudcroft ips (/. cloudcrofti Sw.) is a secondary enemy of 

 pines in the high mountains of New Mexico. It is a slender species 

 with five pairs of spines on the elytral declivity and is closely related 

 to /. confusus in character and habits. 



The emarginate ips (/. emarginatus Lee.) is most frequently found 

 associated with the mountain pine beetle in its attacks on ponderosa 

 pine, lodgepole pine, and sugar pine, and with the Jeffrey pine beetle 

 in Jeffrey pine, but is quite capable of and occasionally does kill trees 

 on its own account. This is the largest western species of Ips. Its 

 range extends through California, north to southern British Colum- 

 bia, and east through Idaho to western Montana. The adults are 

 dark-brown, cylindrical bark beetles about one-fourth inch in length, 

 with three prominent spines along each side of the elytral declivity, 

 and a fourth nearly obsolete spine. Their work is characterized by 

 the long, straight, nearly parallel egg galleries from 2 to 4 feet in 

 length, which run up and down the tree and connect at different 

 points (fig. 55). Owing to the similarity in length and width of the 

 Qgg galleries, its work is often confused with that of the mountain 

 pine beetle with which it is so often associated. However, the pres- 

 ence of a nuptial chamber and the absence of packed boring dust in 

 the Ips galleries will distinguish their work. In the northern part 

 of its range this species has two complete generations a year, while 

 in the southern part there are a number of summer generations with 

 considerable overlapping of broods. Control work has included this 

 species when in association with more aggressive bark beetles, but no 

 separate control ever has been required. 



130643°— 39 8 



