588 



THE MONTHLY BULLETIN. 



6. The branch and twig borer is generally distributed throughout the 

 State. 



7. The live oak appears to be the native food plant but grapes and 

 nearly all the pome fruit trees are attacked. 



Damage. 



Within the last two months there have been repeated calls to this 

 office for information regarding an insect which was apparently doing 

 considerable damage to young fruit trees in various sections of the 

 State. The seriousness of the attacks this year led many to believe that 

 a new fruit pest had appeared. In not a few cases young orchards 

 have been seriously injured by the excessive pruning caused by the 

 twigs breaking off at the burrows made by the insect. Large branches 

 are not seriously injured except that the tunnels afford excellent hiber- 

 nating quarters for other insect pests and ready breeding places for 

 parasitic fungi. The damage to the small twigs is due to the large 

 burrows which so weaken them that they can not sustain their own 

 weight and thus break. Small olive trees have apparently suffered 

 most. 



Pig. 339. The branch and twig buier, Polycaon 

 confertus Lee. Beginning at the left : beetle at 

 work in burrow ; adult f ema le and male beetles ; 

 twig sliowing entrance of burrow ; twig broken at 

 the burrow. All natural size. (Original.) 



In spite of the above record it does not appear that the insect has 

 ever been a really serious pest except occasionally. Records dating as 

 far back as 1883 show the same conditions to have existed then. 



H. F, Wilson and A. L. Lovett^ report the following conditions in 

 Oregon: "Although apparently never doing any amount of damage, 

 this insect is often found attacking the stems and branches of pome 

 fruits and even grapes. * * * They have never been abundant 

 enough to cause any great alarm, but the burrows offer excellent oppor- 

 tunity for the entrance of fungi and decay organisms." 



It is not likely that the insect will become a more serious pest in the 

 future. 



"Biennial Crop Pest and Horticultural Report, 1911-1912, p. 161. 



