RECENT WORK WITH HYDROCYANIC ACID GAS 2OI 



treated when vines were in full bloom with the follow- 

 ing : Cyanide, 18 ounces; acid, 27 fluid ounces; i 

 quart of water. The temperature was 60 F. Time 

 of exposure was half an hour. The work was done 

 after sunset. The mealy bug was destroyed, foliage 

 unhurt, but three-quarters of the bloom was injured. 

 A few mealy bugs appeared at the close of the season, 

 after the grapes had been gathered. A second fumi- 

 gation was therefore decided upon and the results were 

 satisfactory. 



Vinery B had a capacity of 3,825 cubic feet and 

 contained a late variety. It was treated before vines 

 bloomed with the following dose: Cyanide, 27 ounces; 

 acid, 40 ounces; water, 60 ounces. The application 

 was made after sunset and exposed three hours at a 

 temperature 60 F. The mealy bug was destroyed 

 and there was no injury to vines. A few insects ap- 

 peared in the autumn and a second fumigation was 

 given, with the same success as in the previous case. 



Vinery C had a capacity of 1,990 cubit feet and 

 was planted with an early variety. It was treated 

 when the grapes were the size of peas with the follow- 

 ing chemicals : Cyanide, 6 ounces; acid, 9 ounces; 

 water, 15 ounces. The temperature was 65 F. ; 

 weather very sultry at the time. Time of exposure 

 was forty minutes and application was made at 3 

 P.M. The grapes were browned and killed, while the 

 foliage was uninjured. The mealy bug was de- 

 stroyed. The vinery was kept on the cool side, plenty 

 of air given, and splendid growth and promise of fruit 

 for next year was obtained. A few mealy bugs ap- 

 peared in October. Fumigation was repeated. All 



