October, '22] quayle: codling moth control in walnuts 371 



It therefore appears that rapidity of death by starv^ation occurs in 

 direct proportion to the work the bees are called upon to do, and that 

 when death from starvation occurs rapidly there is still a food reserve 

 which has not been depleted. The relation between the work done 

 and the death rate is quite in keeping with what has been so frequently 

 observed for normal bees, namely that the normal term of life (barring 

 accidents) is determined by the amount of work which the individual is 

 called upon to do. Since bees in cages are not under normal conditions, 

 they probably do more work than bees under ordinary hive conditions, 

 as indicated by the fact that those on satisfactory foods do not live as 

 long as bees are known to live in the hive. The longest period of life 

 in these cages that has come to the writer's attention were some that 

 lived for thirty days in a cool laboratory room. In the series here 

 recorded, the last bee on sucrose died on the seventeenth dav- 



DUSTING VERSUS SPRAYING FOR THE CODLING MOTH 



IN WALNUTS 



By H. J. Quayle 



During the past three years a considerable acreage of English wal- 

 nuts in Southern California has been dusted for the codling moth. 

 During the first year standard or acid arsenate of lead was used but 

 which was later abandoned because of the injury to the walnut foliage. 

 Only basic or neutral arsenate of lead can be used with safety on Eng- 

 lish walnuts at least in the coastal sections of Southern California. 

 In connection with the writer's investigation of the codling moth in 

 walnuts, spraying was compared with dusting as a means of control. 

 For this purpose four different orchards have been utihzed where plots 

 were sprayed and dusted at different times, and plots left as checks, 

 during the past three seasons. A tabular summary of the results of 

 dusting and spraying on two of these tracts for one season, which are 

 representative, is given below: 



Reduction in wormy nuts by one spraying 



" " " " " " dusting 

 Infestation of check plot 

 Average production per tree 

 Increase in sound nuts per tree by one spraying 



" " " " " " " " dusting 



Value of spraying per tree, nuts at 25c 

 Value of dusting per tree, nuts at 25c 

 Cost of spraying per tree 



