INSECT ENEMIES OF WESTERN FORESTS 



85 



There are a large number of other budmoths and leaf rollers that 

 infest the buds and young, tender leaves of various broadleaved 

 trees and shrubs. This damage is often of a serious nature in 

 orchards but seldom is of any importance in the forest. No attempt 

 can be made to discuss these interesting but relatively unimportant 

 species. 



NEEDLE MINERS 



Some leaf -eating insects have 

 the habit of feeding internally 

 on coniferous needles and thus 

 protecting themselves within a 

 thin, leafy covering. These are 

 called needle miners. A great 

 many of them cause only an in- 

 significant amount of damage, 

 but a few, such as the lodge- 

 pole needle miner, may defoli- 

 ate extensive areas and con- 

 tribute to the destruction of 

 the timber cover on entire w^a- 

 tersheds, as has happened in 

 parts of the Yosemite National 

 Park. The needle miners be- 

 long mostly to one small genus 

 of moths. 



Outbreaks of needle miners 

 are eventually brought under 

 control by the action of native 

 parasites and the influence of 

 climatic conditions. ^Direct con- 

 trol through the use of the ordi- 

 nary sprays or dusts offers 

 little hope of being effective 

 since the insects work within 

 their protective covering and 

 would not be reached by these 

 poisons. Eecent experiments 

 indicate that light, penetrating 

 oil sprays to which nicotine has 

 been added offer promise of 

 being effective. 



The lodgepole needle miner {Recurvaria milleri Busck) (66) 

 (fig. 42) is the best representative of this group in the West. As its 

 name implies, it mines the needles of lodgepole pine and is found 

 through the lodgepole pine forests of the Sierra Nevada in California. 

 It has defoliated extensive areas of lodgepole pine in the Yosemite 

 National Park and so weakened the trees that they readily succumbed 

 to the attacks of the mountain pine beetle. The adults are very small 

 white or grayish moths only about one-half inch long. The cater- 

 pillars are very small greenish w^orms with black heads. In the 

 Yosemite National Park this species has a 2-year life cycle, the moths 

 flying in alternate years. 



Figure 42. — The lodgepole needle miner {Re- 

 curvaria milleri), X 2.25. 



