INSECT INFESTATION IN HAYFORK 7/ATERSH2D. 



A v-rr:' serious infestation of the ywllovr pine 

 !er by Insects has developed in Ranger District !Io. S. 

 hoavieat infestation occurs over the plain and hills 

 of Hayfork Valley, but extends also up into the yello-.: pine 

 timber on tbe higher slopes of the Hayfork watershed. 



In addition to the work of the insects, tho loaf 

 fungus Lophodermium appears to be at work on the yellow pines. 



.? damage has not been examined by a plant pathologic t, 

 but canplen of the infected needles ar9 being cent to the 

 District Forester for examination and it is hoped that & 

 representative of the Bureau of Plant Industry will be aMe 

 to" pay a visit to the infested region during the spring or 

 summer. The needles killed by this fungus hang on the tree 

 for a considerable time after they die and 017 hundreds of 

 trees the needles have all been killed except those of last 

 season's growth; on such trees these dead needlos far out- 

 number the reon needles, giving the trees a sickly yellow 



earance. Like the innect damage, this fungous injury 

 is" moat pronounced in the Hayfork valley. T/idespread in- 

 Jury from this cause, observed in connection v;ith the large 

 number of trees killed by the beetles, has attracted th* 

 attention of all residents of Hayfork Valley and has oauoed 

 considerable comment as to the unhealthy appearance of the 

 stand. 



This needle fungus, by partial defoliation of the 

 trees, will undoubtedly check their rate of growth. If the 

 funguo attack dies out it is very likhly that the trees will 

 resume their normal appearance and rate of growth within a 

 few yee.rs. If the attack continues year after year the trees 

 may possibly weaken sufficiently to induce an attack by 

 flat-headed borers or other enemies. The needle fungus alone 

 would probably not be sufficient to entirely kill the trees. 

 Further information as to the effect of this blight will be 

 available after the advice of a pathologist has been secured. 



The most serious injury, however, and the one in- 

 volving the greatest loss of timber, is the work of the tree 

 destroying beetles. The chief agency of this destruction 

 ie the western pine bark beetle, Dendroctonus brevicomis. 

 The adults of this beetle girdle the trees when they make 

 their egg galleries. The larvae feed in th* bark and change 

 to the adult state in the outer bark and then leave the tree 

 during the spring and summer and infest new trees. Yellow 

 pine trees of any size from saplings to the largest mature 

 trees are subject to attack. A good description of this 

 beetle and of its work and habits is given by ilr. Hopkins 

 in the reprint from Bulletin No. 83. Part I, of the Bureau 

 of Entomology, a copy of which should be in each Ranger's 

 library. 



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