36 THE FIG MOTH. 
EXPERIMENTS WITH FUMIGANTS AT A HIGH TEMPERATURE. 
[By F. H. Chittenden and Thos. H. Jones.] 
On May 18, 1911, the first good opportunity to test one of the fumi- 
gating gases against " worms " in figs was afforded. The desire was 
to have a high temperature, similar to that of Smyrna, and to make 
a test to determine if the insects could be destroyed at a profit in a 
short exposure. These experiments were conducted at Washington, 
D. C. 
BISULPHID OF CARBON. 
Since the majority of the fig-moth larvae were dead and had been 
replaced in many instances by the Indian-meal moth {Plod la inter- 
punctella Hiibn.) during spring, figs infested by this latter species 
were used. The bisulphid of carbon was used at the rate of 1-|- pounds 
to 1,000 cubic feet of air space, and the figs were placed in a specially 
prepared and very nearly air-tight fumigating box at 4.30 p. m. At 
this time the temperature was 90° F. When removed 21 hours later 
the temperature was exactly 100° F. The mean temperature was 
estimated at 96° F. 
The figs were very thoroughly infested with the Indian-meal moth, 
there being an abundance of moths and larvae. All were dead when 
examined on the morning of May 20. It is therefore safe to say that 
the fig moth can be destroyed in figs in an inclosure made sufficiently 
air tight, in a temperature between 90° and 100° F., which is apt to 
be encountered at Smyrna, and in a building especially constructed 
for this purpose, using 1^ pounds of bisulphid of carbon to 1,000 
cubic feet of air space. There is no necessity for a longer exposure 
if the building is nearly air-tight, as in this case. The odor of bisul- 
phid of carbon was quite perceptible when the insects were removed 
from the fumigatorium and was even perceptible in another room, 
to which the insects were removed, when opened the next morning. 
Up to June 3 no evidence of eggs hatching could be observed. The 
mass of figs fumigated was very carefully examined and no trace of 
young larva3 or eggs could be found. Eggshells, however, were seen 
and one nearly mature larva was still living, being incased in an un- 
usually strong, somewhat leathery cocoon, placed tightly between two 
figs. With the amount of figs used in the experiment, this might be 
considered a perfect fumigation, since a single moth could not pro- 
create and reproduce its kind. 
It should be said that the Indian-meal moth (Plodia interpunc- 
tella Hiibn.) is of about the same size as the fig moth in all its stages. 
Therefore there would be practically no difference in the resistant 
power of the two species against any gas which might be employed. 
c It has already been recorded that these two species have been observed in coitu, but 
the resulting eggs were not fertile. 
