76 
SEVENTH ANNUAL MEETING OF THE 
quite thorough fumigation tests on the White Fly with very 
excellent results. The treatment was made about the middle 
of February of this year (1894) and was so successful that it 
was only by careful search (in treatments with certain 
strengths of material) that one could find a living insect. 
Fumigation is accomplished b} 7- passing over the tree a tent 
of some closely woven material (eight-ounce ducking, lor in¬ 
stance) which has been oiled and painted black, if the treat¬ 
ment is to be made by daylight. After the tent has been 
placed over the tree the edges are held down by a few shovel¬ 
fuls of earth thrown on here and there. The operator now 
places under the tent in an earthen or glass jar, the material 
for generating the gas. For this purpose crude potassium cy¬ 
anide, commercial sulphuric acid and water are used in vary¬ 
ing quantities, according to the size of the tree. A tree six¬ 
teen feet high, and having a spread of twelve feet will require 
about eight ounces of potassium cyanide, eight fluid ounces of 
sulphuric acid and sixteen fluid ounces of water. The water 
and sulphuric acid are placed together in the earthen vessel 
and placed by the operator under the tent. The potassium 
C} 7 anide is then dropped in, and the operator quickly with¬ 
draws from the tent, closes the opening, and allows the treat¬ 
ment to continue for thirty to forty minutes. The tent is then 
removed and the operation is complete. To work this method 
economical!} 7- , from four to six tents must be used in order to 
keep the laborers busy during the delay, while the gas is 
acting. 
Careful descriptions of the methods for fumigation are given 
in the various bulletins and reports of the Division of Entom¬ 
ology of the United States Department of Agriculture. The 
latest of these are: The Gas Treatment for Red Scale, Bul¬ 
letin 23, Division of Entomology; Hydrocyanic Acid Gas as 
an Insecticide, Insect life, volume VI., (1893) page 176; and 
A Hew Fumigator for Scale Insects, Insect Life, valume V., 
page 328. The above articles were prepared by Dr. W. D Co- 
quillette, the originator of the gas method of treating insects. 
Prof. A. H. Morgan, of the Louisiana Agricultural Experi¬ 
ment Station, Baton Rouge, has given a plain account of the 
methods of fumigation in a special bulletin: On the Orange 
and other Citrus Fruits. 
The details of application would require too much time for 
their explanation, to consider further here. We can say pos¬ 
itively, however, that this method of treatment is veiy effect¬ 
ive. All of you have sprayed trees and know how hard it is 
to reach all portions of the tree, and in treating such a pest as 
this, every insect must be covered by the spray to be killed. 
Many thus escape, no matter how thorough we spray. After 
