10 BULLETIN 295, T7. S. DEPARTMENT OF AGRICULTURE. 



REMEDY. 



There is probably no other seriously injurious insect which can be 

 eliminated with less expense and trouble than the Zimmerman pine 

 moth, because practically everywhere, wherever its existence is caus- 

 ing real damage, the country is readily accessible, being either 

 already logged over or adjacent to settled farming land. 



In slashings the remedy consists in logging, thus removing the 

 mature trees as soon as the area is reseeded, and in any other wood lot, 

 where it shows its presence in the second growth, in merely using all 

 " spike-topped," lightning-struck, and heavily branched mature trees 

 for firewood or domestic purposes. These are the "brood trees" in 

 the great majority of cases, and then disposal ends the trouble in 

 the growing trees. The larva in these three types is found at the base 

 of the spike, along the scar caused by the bolt, and in the knobby 

 growths on the branches which are the result of primary injury by 

 Pinipestis cambiicola (in the West) and probably other insects. The 

 affected parts should be destroyed, the simplest way being to burn them 

 before the arrival of spring. The judicious choosing of the right trees 

 for firewood for home consumption alone would prevent on many farms 

 further damage by this insect to the growing trees. In one wood lot 

 east of Missoula, Mont., covering about 40 acres of a quarter-section 

 farm, 25 per cent of the second growth had been infested annually 

 for several seasons, and the cutting of only three overmature trees 

 during 1913-14 for firewood ended the damage absolutely. One of 

 them was a still infested spike-top and two were full of knobby 

 branches, also infested. There are still about 80 overmature trees 

 standing on that farm, but the three cut were evidently, as supposed 

 before the cutting, the only" brood trees," and, as the woodpeckers had 

 taken care of the infestation in second-growth trees, the elimination 

 of the moth at that place was a natural result of the disposal of 

 these trees. (Pis. X and XL) 



In a locality about 5 miles north of Missoula, Mont., where at 

 least 3,000 second-growth trees are infested and reinfested annually, 

 the writer is positive that the cutting of not more than 24 over- 

 mature "brood trees" in a stand of about 1,000 of the same age as 

 these would effectively end the continuous depreciation. In other 

 localities not so thoroughly examined, the proportion of work 

 necessary to end the trouble appears to average about the same. 

 Even in southeastern Montana, though the moth is not subject there 

 either to woodpeckers or parasites, the insect damage could be 

 greatly reduced, if not eliminated, by disposing of the "brood trees" 

 by merely selecting them for fuel. 



