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REPORT OF THE ENTOMOLOGIST. 133 
REPORTS OF AGENTS. 
REPORT ON THE GAS TREATMENT FOR SCALE-INSECTS, 
By D, W. CoQuiLuertT, Special Agent. 
Los ANGELES, CAL., January 20, 1888, 
Str: I have the honor to transmit herewith my report upon the gas treatment for 
scale-insects (Coccid@), 
Shortly after my re-appointment last July as an agent of your division the 
supervisors of this county withdrew their offered reward of ¢?.000 for a perfect 
exterminator of the Icerya, and their reason for so doing is thus given by the Los 
Angeles Herald: 
On Saturday last the board of supervisors decided to rescind the reward of 
$1,000 which they had offered for the discovery of a remedy which would exter- 
minate the White Scale Bug and other pests injurious to fruit trees. They came to 
this decision for the reason that it is eyed that Mr, Coquillett, the Government 
appointee, has by his gas systera mastered the problem which has so long been a 
puzzle to all fruit-growers.” 
My experiments have been conducted in the orange groves of Mr. J. W. Wolf- 
skill, of this city. Both Mr Wolfskill and his foreman, Mr, Alexander Craw, have 
aided me much in my work, as has also Mr. W. G. McMullen, one of the members 
of the Los Angeles County Horticultural Commission, 
Your own advice and frequent expressions of confidence have done much toward 
giving to my work whatever of merit it may possess, 
Very respectfully, 
D. W. CoQuiLiLett, 
Special Agent, 
Prof, C. V. RILEY, 
U. S. Entomologist. 
THE GAS TREATMENT FOR SCALEH-INSECTS. 
The process of destroying insects on plants in hot-houses by fumigating with sul- 
phur, tobacco, and various other noxious substances, has long been in vogue, but 
up to a recent date this mode of warfare against insect pests has not been extended 
to trees and plants growing in the open air. The earliest record I possess of any at- 
tempt of this kind is a copy of the specifications for a patent (No. 64667) granted 
to Mr. James Hatch, of Lynn, Mass., on the 14th of May, 1867. The following ex- 
Lie from these specifications will sufficiently explain the method pursued by Mr. 
atch: 
‘*«The invention relates particularly to the manner of effecting the destruction of 
insects known as Canker-worms, after their lodgment in trees and while consum- 
ing the foliage thereof. * * * Icover the entire head of the tree with a thin cloth 
of close texture, drawing the edges around the trunk, soas to envelope the branches 
in a sort of sack, Near the tree I have a furnace, over which is placed a pan con- 
taining tobacco, pepper, or other substances, the smoke from which will stupefy or 
kill the worms; and from this pan [ lead a pipe directly into the sack. Applying 
heat to the pan by a lamp or by fuel introduced into the furnace, the smoke gen- 
erated from the tobacco or other substance in the pan is thrown into the sack and 
soon fills it, coming into contact with all the leaves, and either killing or instantly 
dislodging every worm and all other insects that may be in the tree.” 
This method of destroying insects on trees could not have been very widely 
adopted. Dr.A.S. Packard, who for several years held the office of entomologist to 
the Massachusetts State Board of Agriculture, writes me that he is not aware that 
this method has been practiced in any part of the Atlantic States. I can find no 
reference to it, nor to any similar method having been used in any of the States east 
of the Rocky Mountains from the date of the Hatch patent up to the present time. 
For several years past many attempts at destroying scale-insects with gases and 
fumes have been made in southern California. For this purpose the infested tree 
was inclosed in an air-tight tent thelower part of which was either fastened around 
the trunk of the tree or allowed to fall upon the ground; in the latter case a small 
