Table 4 also showed that even as the vapor concentrations dropped, they were 

 still high enough at all times to cause high mortalities to caged drosophila. The 

 lowest mortality recorded was 85 percent. The lowest mortalities recorded for 

 caged pineapple beetles were 26 percent and 41 percent, both recorded during the last 

 2 weeks of operation. Mortalities for caged dried- fruit beetles for the same period 

 were 5 and 22 percent. These were also the lowest mortalities recorded for this 

 insect. Concentrations of dichlorvos ranged from 6.9 to 4.6 /Kg/cu. ft. during these 

 last 2 weeks and the generator was operated on a daily basis to maintain effective 

 control of drosophila in the cellar. Higher concentrations of dichlorvos than most of 

 those reported here would be required if the dried- fruit beetle were also a serious 

 pest in the cellars. It should be remembered, however, that the caged insects were 

 exposed only for the time the vapor generator was in operation, and the vapor 

 concentration readings were made at the time the generator was turned off and 

 directly in front of the machine . 



A single test was conducted in 1966 to find how rapidly the dichlorvos vapors 

 disappear from the air after the generator has been turned off (table 5) . The 

 original dichlorvos concentration of 4 jug/cu. ft. is possibly a little low to give a 

 good picture of the dispersal rate, but the concentrations being given off by the 

 generator were not known until the samples were analyzed later. One- half hour after 

 the treatment, 9 percent of the dichlorvos had been lost from the air, and after 1 

 hour, 50 percent. 



Dichlorvos concentrations measured 3 hours after each treatment during the 

 last four tests of the 1966 season are shown in table 6. The average loss in th6se 

 four tests at 3 hours is higher than in the single test at 4 hours. 



The taste panel conducted in 1966 by the Food Science and Technology Depart- 

 ment of Oregon State University found no off-flavor in either sherry or tokay wines 

 stored in covered wooden wine tanks for 15 treatments or exposed directly to the 

 vapor for 3 hours. The 15 treatments included 33 hours' operation of the generator, 

 with vapor concentrations from 4 to 56 )Ug/cu. ft. being recorded after individual 

 treatments. Air concentrations at the end of the 3~hours operation of the vapor 

 generator measured 8 jug/cu. ft. where the wine was exposed in open beakers. 



Residue tests made on the same samples mentioned above showed that 

 residues of dichlorvos were less than 0.03 p. p.m. , or below the range of 

 sensitivity of the analytic method. 



