INSECT ENEMIES OF WESTERN FORESTS 37 



borers are very similar to flatheaded borers, except that the body is 

 usually thicker and has a horny plate only on the upper surface of 

 the first enlarged seg-ment. The larvae feed under the bark and 

 through the deadwood of the killed twigs, forming broadly oval 

 tunnels which are filled with boring dust. The beetles that are most 

 frequently involved in tliis type of damage are the following : 



Species Hosts and distribution 



Oncideres trinodatus Casey Mesqiiite, huisache, luiajilla, and Parkin- 



sonia. Texas, New Mexico, and Arizona. 



Oncideres quercus Skinner Oak. Arizona. 



Oncideres pustulatus Lee Mesquite. Texas, New Mexico, Arizona, 



and California. 



Other species of roundheacled borers which may be found in twigs 

 and branches of western forest trees include the following : 



Species Hosts and disti-ibution 



Opsimus quadrilineatus Mann Spruce, fir, hemlock, and Douglas fir. West- 

 ern States. 



Oeme costata Lee Ponderosa and pifion pine. Colorado and 



Arizona, 



Oenie strangulata Horn Cypress and juniper. Arizona. 



CaUidium hirtellum Lee Ponderosa pine. California and Oregon. 



CaUidium hardyi Van D Douglas fir, fir. Pacific coast. 



Call idi ion calif ornicum Casey Juniper and cedar. Oregon, California, and 



Nevada. 



CaUidium pseudotsugae Fisher Douglas fir. California and Oregon. 



Neoclytus muricatulus Kirby Spruce, larch, Douglas fir, and pines. West- 

 ern States. 



Pogonocherus oregonus Lee Fir. Western States. 



Pogonocherus crinitus Lee Oak. California to British Columbia. , 



Oherea ferruginea Casey W^illow. Colorado. 



TWIG MOTHS AND TIP MOTHS 



The caterpillars of a large group of moths bore into and feed on 

 the fresh, tender bark, and cambium layers of growing terminal and 

 lateral shoots. Their feeding causes the deformation or death of 

 these parts and results in a many-branched, poorly shaped tree, and 

 in some instances results in the tree's death. Such damage is par- 

 ticularly serious in young plantations or to cut-over lands where a 

 second crop of straight, vigorous trees which will produce sound 

 lumber in the shortest possible length of time is desired. Older trees 

 also are attacked by these moths, but the damage is much less con- 

 spicuous and of little significance. 



Damage of this type is caused principally by the caterpillars of 

 moths belonging to the genera Dioryctria and Pinipestis of the 

 family Pyralidae and the genera Rhyacionia^ Petrova^ Eucosma^ 

 and Laspeyresia of the family Eucosmidae. 



The control of cambium-feeding twig and tip moths is a very dif- 

 ficult undertaking, and as yet no completely satisfactory methods 

 have been evolved. Spraying with a light miscible oil in May, at the 

 time the eggs are hatching, has given fair results, but the time of 

 application is such an important consideration that the method 

 should be used only with the advice of an expert. The use of other 

 sprays is still in the experimental stage. Hand picking of the in- 

 fested tips offers some hope of control on small valuable plantations 

 that are isolated from sources of reinfestation. 



