202 FUMIGATION METHODS 



the bugs were destroyed. The season had so far ad- 

 vanced, however, that the 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. 



A conservatory of 300 cubic feet, containing mixed 

 flowers and ornamental plants and ferns, etc. , infested 

 with aphis and mealy bug was fumigated after sunset 

 with cyanide, 8 ounces; acid, 12 ounces; water, 20 

 ounces. The temperature was 50 F. Time of ex- 

 posure was three-quarters of an hour, with complete 

 success. There was no injury to maidenhair fern 

 or any of the plants under treatment. The cost did 

 not exceed i shilling. 



A greenhouse of 2,000 cubic feet, containing chrys- 

 anthemums in full bloom severely infested with green- 

 fly, was treated one hour before sunset with cyanide, 

 3^ ounces (0.05 gramme per cubic foot) ; acid, 5 

 ounces ; water, 9 ounces. The temperature was 52 

 F. and the time of exposure was 25 minutes. Every 

 aphis was killed, also slugs, flies, wasps and butter- 

 flies. A toad was uninjured. Not a petal or leaf was 

 hurt. 



Conclusions. Mr. Cousins is of the opinion that 

 these experiments should encourage practical men to 

 give cyanide fumigation a thorough trial for such 

 pests as are beyond ordinary treatment. For green- 

 house work he recommends the following : If the 

 house be under 10,000 cubic feet one vessel will suffice; 

 if over, provide a vessel for each 10,000 cubic feet. 

 Arrange the ventilators so that they can be opened 



