FUMIGATION WITH HYDROCYANIC ACID GAS. 
805 
the bloom injured. A few Mealy Bugs appeared at the close of the season, 
after the grapes had been gathered. A second fumigation was therefore 
decided upon, and the results so far have been completely satisfactory. 
Vinery B. 
Capacity, 8,825 cubic feet. 
Late variety. Treated before vines bloomed : 
Cyanide, 27 oz. ; acid, 40 oz. ; water, 60 oz. 
Time, 3 hours. After sunset. Temperature, 60 deg. F. 
Besult. — Mealy Bug destroyed. No injury to vines. A few appeared 
in the autumn, and a second fumigation was given, with the same success 
as in the previous case. 
Vinery C. 
Capacity, 1,990 cubic feet. 
Early variety. Treated when grapes the size of peas. 
Cyanide, 6 oz. ; acid, 9 oz. ; water, 15 oz. 
Temperature, 65 deg. F. ; weather very sultry at the time. Time, 40 
minutes ; 8 a.m. 
Result. — Grapes browned and killed. Entire crop lost. Foliage un- 
injured. Mealy Bug destroyed. 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 appeared in October. Fumigation 
was repeated. All the bugs were destroyed. The season had so far 
advanced, however, that eggs were to be found on the shoots. Painting 
the rods with the winter alkali wash in the spring and a fumigation before 
the bloom appears to have been decided upon. 
Conservatory. 
3,000 cubic feet, containing mixed flowers and ornamental plants, 
ferns, &c. Infested with aphis and Mealy Bug. Cyanide, 8 oz. ; acid, 
12 oz. ; water, 20 oz. 
Temperature, 50 deg. F. (after sunset). Time, three-quarters of an 
hour. 
Complete success. No injury to maidenhair ferns, or any plants under 
treatment. Cost Is. 
Greenhouse. 
2,000 cubic feet ; containing chrysanthemums in full bloom, severely 
infested with green fly : 
Cyanide, 3^ oz. (-05 gramme per cubic foot) ; acid, 5 oz. ; water, 9 oz. 
Temperature, 52 deg. F. Time, 25 minutes ; one hour before sunset. 
Besult. — Every aphis killed, also slugs, flies, wasps, butterflies. A 
toad was uninjured. Not a petal or leaf was injured. Cost 6d. ; ^Icl. per 
1,000 cubic feet. 
Conclusion. 
These experiments should encourage practical men to give cyanide 
fumigation a thorough trial for such pests as are beyond ordinary treat- 
ment. Although the cyanide fumes are poisonous in the extreme, if care 
be taken there is absolutely no risk to the operator. For outdoor work 
stand to windward when removing the waterproof cloth. If the cyanide 
