16 MONTANA EXPERIMENT STATION BULLETIN 384 



gether. When they are full grown they are about one-half inch 

 long and white or slightly pink in color. Not especially abundant 

 in Montana, this species has been reported from Bozeman, Hardin, 

 Miles City, and Moore. 



Indian Meal Moth (Plodia interpunctella (Hbn.)). — The adult 

 of this species is a conspicuously marked little moth. The outer 

 two-thirds of the forewings are copper brown, and the inner 

 third is whitish gray. The wings expand to about three-fourths 

 of an inch. The larvae, when fully developed, are about one-half 

 of an inch in length and are dirty white with occasionally a green- 

 ish tinge. They web the materials which they infest and may 

 feed on grain, grain products, dried fruits, nuts, and similar food 

 stuffs. They have been reported from Billings and Bozeman in 

 the State. 



Control of Grain Insects 



Damage from grain insects may be greatly reduced if protec- 

 tive measures are taken to prevent infestations. Bins in which 

 grain is to be stored should be thoroughly cleaned before new grain 

 is stored. New bins should be so constructed that they are off 

 the ground, and that grain cannot accumulate beneath the floor, 

 between walls, etc. Dry grain should be stored, and there should 

 be good ventilation; it is said that grain containing seven or eight 

 per cent moisture is too dry and hard for most insects and that 

 several cannot exist in flour containing eleven per cent or less 

 moisture. Steel or concrete bins are more desirable than wooden 

 structures. Old grain sacks should not be stored near granaries 

 and should not be used again until they have been fumigated or 

 otherwise freed of live insects. 



Stored grain which has become infested with grain pests is 

 best treated by fumigation, and carbon disulphide is the most econ- 

 mical and efficient material which can be used for this purpose. 

 This compound is a colorless, rapidly evaporating liquid, which is 

 approximately one-fourth heavier than air (1.26:1). If properly 

 applied to the top of a bin it penetrates downward, killing the in- 

 sects without injuring the grain. It should be remembered that 

 carbon disulphide is inflammable and under certain conditions ex- 

 plosive. Even lighted cigars or cigarettes should be kept away 

 from a building being fumigated with this material. The bin to be 

 treated should be made as tight as possible, and one pound of carbon 

 disulphide should be used for every 100 cubic feet or 80 bushels of 

 grain. Shallow pans may be imbedded in the surface of the grain 

 and the liquid poured into them and allowed to evaporate, or it 

 may be poured over old sacks or blankets thrown into the bin. 

 Fumigation should not be attempted at temperatures below 60°F. 

 U. S. D. A. Farmers' Bulletin 1483 gives further information on 

 this subject. 



