s 
64 BULLETIN 737, U. S. DEPARTMENT OF AGRICULTURE. 
to insure perfect fitting of the door. The closet was fitted with 
removable trays to insure easy and rapid handling of the cigars. 
The trays have bottoms of one-half-inch wire screen. 7 
Fumigation is more effective when the temperature is high, and 
it is not advisable to use carbon disulphid when the air temperature 
is much below 70° F. To be fairly effective against all stages of 
the beetle in tobacco, carbon disulphid should be used at a rate of 
not less than 4 pounds to 1,000 cubic feet of space. When only 
a small space is to be fumigated and the cost of the treatment is 
consequently slight, the exact amount of the carbon disulphid used is 
of no particular importance, even if the amount is very much in excess 
of the dosage advised above. The pericd of exposure should be from 
24 to 48 hours. The results obtained in a number of experiments 
with carbon disulphid are given in Table IX. The time of exposure 
was 24 hours, except In experiments 5 and 11, in which the time 
of exposure was 48 hours. 
TaBLeE IX.—E-erperiments with carbon disulphid in contro! of the tobacco beetle 
(Lasioderma serricorne). Experiments at Clarksvitle, Tenn., 1915. 
Dosage 
yee Date. Cras a Stage of insect. Placement. Results. 
£62); 
1915. Pounds. 
1} Aug. 3 1 | Larve and adults. ----.- In smoking tobacco. ---- | Partially effective. 
2| Aug. 4 1 | Adults, larve, and pupz -_-_-- op eS Do. : 
3 | Sept. 16 2) Bae (Sf)-- 22 eee In pressed yeast cake....| 3days after treatment, 16 
alive, 71 dead. 
4 | Sept. 4 27) barge CS)i- 2255 eee In wire cage, ne protec- | All killed. 
tion. s 
5| Sept. 3 oo arvwes 2565 s2 ae eee In plug tobacco -.-....-- 2 days after treatment, 4 
alive, 26 dead. 
6 | Aug. 20 3 | Adults, larve, and pupz| In glass tubes with cloth | All killed. 
cover. 
7} Aug. 9 >. | All Stasess4.2 322-2 ee eee pee ee ae Do. 
8 |} Sept. 18 4-1 -arves (22025 2s. 5: oe eas Pmeigars fae 2.5 ee See: 2 days after treatment, 
all dead. x 
9 | Sept. 22 4A stasesto- ok ee In smoking tobacco-.-.-..| No live stages found 2 
days after treatment. — | 
Eggs did not hatch. 
Check eggs hatched 
: II stages kill 
10} Aug. 9 ip AE Stages. 2b ese lee In cigars and refuse | All stages killed. 
tobacco. 
11 | Aug. 17 GSN pal CH eens ones cote We About 50 on leaftobacco_| Eggs did not hateh. 
’ Check eggs hatched 
g normally. 
12 | Sept. 26 10 | Eggs and larve--.-__...- iy GIGATS 225 es Oe eee Cigars kept for 6 months. 
No signs of infestation. 
FUMIGATING WITH CARBON TETRACHLORID. 
Carbon tetrachlorid (CCl,) has been used to a considerable extent — 
as a substitute for carbon disulphid in fumigation. It is not as effi- 
cient an insecticide as carbon disulphid, heavier dosages are required, 
and the cost of treatment is greater. The substance is noninflamma- — 
ble, however, and owing to this property is convenient for use when 
only a small space is to be fumigated where there might be danger 
