THE PLUM CURCULIO IN APPLES 



37 



24 



21 



IB 



15 



12 



9 



6 



3 







I9B8 



NUMBER OF EGGS 

 40£00 



Figfure 5. Time of Oviposition by Flum Cnrcnlio Beetles in Breeding* Cag'es 

 in the Insectary, Waltham, Mass. 



The nnmher of eg"grs nsed in this diagram is computed from a daily record 

 of the actaal nnniber of egfgrs laid by 10 beetles retained from, each semi- 

 weekly collection by jarring- on the dates shown in Fig^nre 4. 



Feeding Period of Beetles, 



Feeding punctures in the fruit are first found in the apples during the last 

 week in May. From then on they increase rapidly until about June 21-25 in 

 which period the greatest number was made in 1926 and 1927. As shown 

 in Figure 6, rather constant heavy feeding continues to the end of July, and 

 in 1928 the actual maximum was reached July 26. Under favorable living 

 conditions, such as were provided in the insectary, some of the overwintering 

 beetles continue feeding until cold weather. This was especially true in 1928 

 when feeding was observed as late as November 17. After September 1, 

 however, feeding by the overwintering beetles is insignificant and in the 

 orchard it cannot be distinguished from feeding by fall-emerging beetles. 



