THE RICE MOTH. 11 



but if the buildings are so constructed that heat of 120° to 130° F. 

 may be applied for several hours, the same result will be accom- 

 plished. 



Secondhand bags should not be used without first disinfecting 

 them and bags previously used for the transportation of cacao beans 

 or other food materials which the rice moth is known to attack should 

 be examined for the presence of the insect in its various stages. When 

 insects are found it is best to establish a quarantine bin, room, or 

 fumigator in which the infested bags may be thoroughly baked or 

 fumigated before they are taken into the main building. If it is 

 desired to fumigate a compartment containing bags filled with cacao 

 beans, rice, or similar material the bags should first be brushed off 

 carefully and the tiers of bags so separated as to leave air space be- 

 tween in order that the gas may penetrate the contents more readily. 

 Even after fumigation there is always a possibility that a small per- 

 centage of the insects may remain and revive. 



DESTRUCTION BY HEAT. 



Treatment of insect-infested stored products by heat is by no 

 means a new remedy, but large-scale work with this method had not 

 been conducted to any extent until about 10 years prior to the time 

 of writing. This method appears to have been first successfully 

 used in the control of mill pests at that time by the Kansas Agri- 

 cultural Experiment Station, for the control of both the Mediter- 

 ranean flour moth and the Indian-meal moth. Soon thereafter Mr. 

 C. H. Popenoe, of the Bureau of Entomology, conducted experiments 

 in Virginia, under the writer's direction, which were quite successful 

 against both of these pests. 



The heat method is equally applicable for the rice moth, although 

 it is valuable only for mills or other structiu"es heated or operated by 

 steam, since it presupposes the installation of necessary heating pipes 

 and radiators. The temperature required, from 120° to 130° F., 

 can be obtained readily in a mill provided with sufficient radiation 

 surface to maintain a winter temperature of 75°. A warm, quiet 

 day should be selected for best results, and the temperature after 

 being reached should be maintained for 8 hours or more in order to 

 insure penetration. Should additional radiation surface be required, 

 it may be provided by the installation of temporary supplementary 

 coils of IJ-inch pipe, which will operate to best advantage if placed 

 near the floor. In mills where a complete installation is required, 

 radiators should be calculated on a basis of 1 foot of heating surface 

 (2^ linear feet of 1^-inch pipe) to from 50 to 100 cubic feet of space, 

 depending on the construction of the building and the situation of 

 the coils. The maximum figure should be applied to the lower floors. 



