28 



MASS. EXPERIMENT STATION BULLETIN 249 



Table 3. — Tho Average Number of Beetles Collected from Different Varieties 

 of Apple Trees by Jarring from May 10 to July 26. 



NATURE OF INJURY. 



Injury to apples results from punctures by the beetles and from burrows by 

 the larvae. There are four distinct kinds: namely, egg punctures, early 

 feeding punctures, larval burrows, and late feeding pimcturcs. The different 

 kinds of punctures are clearly shown in Figure I. In addition to these 

 kinds of injury the beetles may eat small holes in the caljrx and petals of 

 buds and blossoms, and in Georgia (10) they feed extensively on peach 

 leaves after the fruit has been harvested. Such injury is seldom seen in 

 Massachusetts, and is of no economic importance. 



Pig-ure 1. Injury to Apple Caused Iby Plum Curculio. (After Fulton (4).) 



<*i<-^ a. Crescent Cut or Egg Puncture, 



surface view. 



b. Early Feeding' Puncture, sur- 

 face view. 



c. Eg'g' Pixncture, cross section. 



d. Early Feeding- Puncture, cross 

 section. 



t. Late Summer Feeding- Punc- 

 tures- 



1. Scars Resulting- from Cres- 

 cent-shaped Eg-g- Punctures. 



m and n. Scars Resulting- from 

 Early Feeding- Punctures. 



An Egg Puncture is distingui.shed by a characteristic crescent-shaped cut 

 through the skin of the young apple about Vs of an inch long and extending 

 into the flesh of the fruit the same distance. Soon after it is made, the edges 

 of the cut form a rough, hard, dark brown scab which enlarges with the 

 growth of the apple until at harvest it becomes a russet scar from H io 1/2 

 inch in diameter, somewhat irregular in shape but resembling an open fan and 

 having little or no trace of the original cut. These scars are slightly raised 

 and on some varieties, especially the Ben Davis, have the appearance of 

 warts. Most egg punctures contain eggs but larvae do not hatch from all 

 eggs and some larvae die before developing to maturity in the fruit. Con- 

 sequently, many egg punctures are not followed by the usual larval burrows. 



An Early Feeding Puncture is a spherical cavity extending about ]/& of an 

 inch into the flesh of the fruit. The entrance to this cavity is perfectly 



