1920] ECONOMIC ZOOLOGY — ENTOMOLOGY. 761 



in the bark and wood are broad and irregular in form. Often several borers 

 work close together, as many as 25 or 30 having been found in a single tree. 

 Infested trees become sickly in appearance. They are inclined to bloom freely 

 and set heavy crops of fruit, but often die in an attempt to bring the crop to 

 maturity. Young trees suffer«most, but trees of all ages are attacked. Trees of 

 an orchard standing near woods are more likely to be injured by borers than 

 those more distant from the woods. 



" In depositing her eggs, the female beetle makes a slit in tlie bark with her 

 mandibles and then inserts her ovipositor and places the eggs between the bark 

 and wood or between layers of the bark. About 9 or 10 minutes are required 

 for the deposition of a single egg. Usually from 2 to 5 eggs are laid at a time. 

 Probably all eggs are deposited by day, and the female in ovipositing sliows 

 a slight preference for the sunny or exposed side of the trunk, 05 per cent of 

 the eggs being found in one case on the exposed side of the tree. In the latitude 

 of West Virginia, the average number of eggs deposited by a single female is 

 apparently from 20 to 30. Oviposition in a given locality extends over a period 

 of from 50 to GO days. 



" The larvje begin to feed immediately after hatching and usually grow rapidly 

 the first season. Feeding is continued until cold weather, and is resumed again 

 in the spring shortly before the blossoming time of the apple. The larva may 

 spend from one to four years in the tree, this stage being of longer duration in 

 the North than in the South. At French Creek, W. Va., 85 per cent of the 

 larvae remained in the trees two years before pupation, and 12 per cent three 

 years. At Winthrop, Me., 25 per cent remained in the tree three years and 75 

 per cent four years. 



" The jiupal stage lasts about 20 days, and the period is about coincident with 

 the blossoming time of apple. After changing to beetles, the insects remain in 

 tlie pupal chamber for from 5 to 10 days and then gnaw a circular hole through 

 the bark at the upper end of the chamber and escape. The beetles appear in the 

 South earliei" than in the North. Between Demorest, Ga., and Munising, Mich., 

 there was a difference of 75 days in the dates of the emergence of the first 

 beetles. At French Creek, W. Va., beetles issued from the wood during the two 

 different years over a period of 30 days. Other years the period was shorter. 

 May 12 was tlie earliest date for the appearance of a beetle in any year at 

 French Ci'eek, and June 23 was the latest date. A few beetles lived 60 days 

 after issuing. 



" Pairing may take place at once or may be delayed 10 days after emergence. 

 Eggs are laid .soon after pairing. In an apple orchard containing 310 King, 341 

 Grimes, and 341 York Imperial trees, the Grimes were most severely attacked in 

 four out of five years, nearly 50 per cent of all the eggs being laid in Grimes 

 trees. This could be accounted for in no other way than that the borers showed 

 a preference for this variety. Expei'iments showed that the fenial(' beetles dur- 

 ing oviposition are capable of flying to a considerable distance, but that they 

 prefer to place their eggs in trees near the place where they themselves have 

 developed. By preventing the development of adults in the orchard trees and 

 in other trees growing within from 300 to 600 ft. of the orchard, subsequent 

 Infestation was reduced 73.6 per cent. 



"The borers have few insect enemies, but woodpeckers play an important 

 part in holding them in check. The downy woodpecker was observed removing 

 borers from trees. 



" No easier and cheaper way of controlling borers was found than the old 



. method of worming trees. The worming should bo done as soon as possible after 



the last eggs of the season have hatched, and should be repeated in the spring 



