6 BULLETIN 243, U. S. DEPARTMENT OF AGRICULTURE. 



The actual amount of loss to sugar-pine seed crops from this 

 source is not easily estimated. Even though a great portion of the 

 crop may be killed, the seriousness of the loss depends upon local 

 factors, such as the desirability of reproduction by the natural re- 

 seeding of the infested areas or the demand for seed by local seed 

 collectors. A number of observations have been made from 1912 

 to 1914 in the vicinity of Ashland, Grants Pass, and Colestin, Oreg., 

 and in California on the Klamath, Shasta, Trinity, California, 

 Plumas, Sierra, and Sequoia National Forests and in the Yosemite 

 and General Grant National Parks. These observations indicate 

 that the sugar-pine cone beetle is distributed throughout the range 

 of the sugar pine, killing a varying percentage of the cone crops. 

 In some places no appreciable damage is found, while in others over 

 90 per cent of the cones are killed by this insect. Apparently, 

 through a period of years, local outbreaks may occur in well-defined 

 centers of infestation anywhere throughout the range. 



RELATION OF CONE-BEETLE DAMAGE TO THAT OF SQUIRRELS. 



The beetle-killed cones fall during a part of the period in which 

 the sugar-pine cones are cut by squirrels. As these rodents are the 

 cause of the cutting and falling of a great part of the cone crop, it is 

 only natural that some of the damage caused by the cone beetle 

 should have been attributed to the squirrel. For this reason con- 

 siderable attention was given to a study of the comparative damage 

 during the season of 1914 from these two causes. 



The first cutting of the cones by squirrels in 1914 was noted on 

 June 25 near Butte Falls, Oreg., and later in July at Colestin, Oreg. 

 Extensive cutting by the rodents did not begin until the middle of 

 July, and they were active from then until the end of summer. Two 

 species, the gray and the Douglas squirrel, were noted in connection 

 with this damage. Important differences, however, readily distin- 

 guish this damage from that of the cone beetle. 



1. Squirrels cut the stalk just above the cone and a part of the stalk 

 is left on the limb. (PI. V, fig. 1.) The wound where the stalk is cut 

 may also show teeth marks of the rodent. Cones which fall from 

 cone-beetle attack have the entire stalk attached to the cone. There 

 are no teeth marks; a small resinous pitch tube is usually found on 

 the stalk. (PI. II, fig. 1.) 



2. Cones cut by squirrels are usually eaten or cached by them. 

 Beetle-killed cones are allowed to lie on the ground where they fall 

 and are unmolested by the squirrels. 



8. The majority of the sugar-pine cones cut by the squirrel- are 

 10 inches or more in length and the seeds usually full size, although 

 they may still be soft and milky. The majority of the beetle-killed 

 cones are less than 8 inches; some of them not over 21 inches. By the 

 time the cones fall the seeds are blighted or hollow. 



