1106 
Journal of Agricultural Research 
Vol. XXVIII, No. II 
The heating of grain caused by insect infestation was known many years 
previous to American observations. It should be recorded that in 1762 Duhamel 
du Monceau and Tillet, in discussing the Angoumois grain moth wrote ( 1 ): 
The emergence of moths is usually preceded by a heating which spreads in the sheaves and piles of grain. 
Thermometers register 25° R. (89° F.) to 30° R. (100° F.) when the exterior air is only 15° R. (66.2° F.). The 
cold of autumn stops development and no more moths are seen until spring. Heat in the grain must be 
generated by the insects assembled in great numbers. Grain heavily infested becomes very warm. No 
heat was noticed in slightly infested grain, and the heat disappeared when most of the moths had emerged. 
Sometimes the heat passes promptly, at others it lasts for 3 or 4 weeks. It may result from a fermentation 
caused by the humidity that insects produce. It is certain that when the harvest is wet and warm rains 
follow, the piles of grain heat in a very short time and the insects breed rapidly. Without doubt, the heat 
is very favorable to the development of the moth, and the damp grain is more easily attacked by the insects. 
In 1760, when it was hot and dry, the people did not expect any insects, but they were very abundant, 
although the wheat did not heat noticeably, until mid-September. In 1761 the grain was very hot, its 
temperature being 53° R. (about 150° F.). Each year, even when harvests are dry, wheat heats inde¬ 
pendently of insects. However, the heat is always greater in infested wheat than in clean wheat, so that 
we can attribute it partly to the insects and partly to the humidity. When humidity causes an increased 
heat, everything is more favorable for the multiplication of the insects and when this multiplication takes 
place, the heat increases still more. 7 
The immediate interest of the writers has been centered in the possibility of 
reducing the temperature of heating grain to normal. In the references already 
quoted regarding the development of heat in grain due to insects, no mention is 
made of preventing the heating by remedial measures directed against the insects 
themselves, except that Back states (16, p. 28-2 Jf) that fumigation with hydro- 
cyanic-acid gas kills Bruchus quadrimaculatus, “reduces the temperature of chick¬ 
peas to normal and stops spread.” However, Herpin (2, p. 9) in 1860 stated that 
hot wheat infested with the Angoumois grain moth cools off in a few days after the 
insects are killed by asphyxiation, and this seems to be the only reference definitely 
answering the query “Will fumigation bring back to normal the temperature of 
grain which has heated as a result of insect attack? ” The writers wish to record 
several opportunities given them to make observations upon this point. 
During the summer of 1918, because of the congested warehousing conditions in 
New York City, one hundred and thirty-seven thousand 240-pound sacks of chick¬ 
peas, grown in Mexico, were held in six large warehouses in New Orleans. In 
October of that year the owners discovered that many sacks were heating badly 
because of infestation by Bruchus quadrimaculatus . Opportunity was given the 
writers to become personally familiar with the problem as presented in the 
various warehouses. Because of the demand for space resulting from war con¬ 
ditions, the sacks of seed had in many instances been stacked 20 deep. Heating 
sacks were found in all warehouses, and as the approaching cold of winter had no 
effect upon the heating sacks, it was recommended that the warehouses be 
fumigated with hydrocyanic-acid gas. In one tier of sacks temperature readings 
were made with ordinary soil thermometers on November 30 and December 1, 
with the results indicated in figure 2. 
The temperature of the warehouse at the time these readings were made was 
58° F. Uninfested sacks registered rather uniformly 60° F., while as noted in 
Figure 2, the temperature of the infested sacks ranged as high as 103° F. On 
December 1 the warehouse was fumigated with hydrocyanic-acid gas, using 
2% pounds of sodium cyanid per thousand cubic feet of space, this being the 
dosage desired by the owners. One week later, after the warehouse had been 
thoroughly ventilated and opened throughout the day for five days, readings 
were again made with soil thermometers. The warehouse temperature outside 
the sacks was 68° F. at 11 a. m. The temperatures secured for sacks numbered 
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 
and 29, were 64°, 65°, 66°, 64°, 68°, 66°, 72°, 65°, 72°, 67.5°, 68°, 67°, 68°, 67°, 
7 Condensed translation, with temperatures in Fahrenheit added. 
