22 UNIV. OF N. II. AGR. EXPERIMENT STATION [Bulletin 238 



LIFE HISTORY OF THE WHITE PINE WEEVIL IS 



COMPLETED 



Gaps in the life history of the white pine weevil have been accounted 

 for during the past year. A large number of individuals have been fol- 

 lowed by W. C. O'Kane through a complete generation from the laying of 

 the eg£!; to the emergence and maturity of the adult. Apparently, some 

 weevils live for two years, and if the number of individuals that exhibit 

 this lengthened cycle is sufficient, this fact may explain some failures to 

 secure control by elimination of infested white pine leaders at the time 

 weevils are in them in the larval or pupal stages. 



Proof is secured that the white pine weevil, Piscodcs strobi, is identical 

 with the so-called species Piseodes approximalus, which is found attacking 

 the roots of stunted white pines. Ap]xirently the P. approximalus repre- 

 sents an infestation of P. strobi, resulting from egg-laying near the ground 

 instead of on the leaders. 



Several species of i)arasites have been collected which may assist in 

 control. (Purnell Fund.) 



PENETRATION OF CONTACT INSECTICIDES 



Observations on the ability of contact insecticides to penetrate through 

 the integuments of different insects begun by W. C. O'Kane seem to indi- 

 cate strongly the vital importance of a chemical compatability between the 

 chemical structure of a spray material and the structure of the integument 

 of the insect. 



Indications are that different groups of insects give different perform- 

 ance in the matter of penetration and toxicity, which is due probably to the 

 differences in the nature of the integument. (Hatch Fund.) 



VARIETY TESTS OF PLUMS 



Japanese sorts of plums such as Burbank and Abundance produce 

 excessively heavy crops. These are not of high quality, and in 1928, 

 reports L. P. Latimer, were marketed with such difficulty that it was often 

 questionable whether or not the cost of picking and transportation to mar- 

 ket could be obtained. The European plums produced good crops this 

 season, but are much more subject to brown rot than the Japanese sorts. 

 This disease was more serious than usual, owing to excessive rain. Several 

 of the Reinette type, namely, Washington, Jefferson, and Imperial Gage, 

 all varieties of white or green flesh, produced fruit of exceedingly high 

 quality this season. Lombard again proved to be the heaviest bearer 

 among the European types. All of the European plums found a very 

 ready market. Our experience in recent years indicates that these sorts 

 deserve wider planting, at least on a small scale. (Hatch Fund.) 



APPLE PRUNING EXPERIMENT 



A good crop of fruit was harvested this year from both the Mcintosh 

 and Northern Spy trees in the pruning experiment. G. F. Potter's 

 review of the records indicates that the prunings for ten years from those 

 trees have amounted to about 15 to 20 pounds of wood each. This has 

 been sufficient in the case of the modified leaders to train the trees to an 

 excellent type of head, in which seven or eight main lateral branches are 





