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Bureau of Plant Industry, Wm. A. Taylor, Chief. 
February 27, 1915. 
A METHOD OF FUMIGATING SEED. 
| By E. R. Sasscer, Chief Inspector, Federal Horticultural Board, and Lon A. Hawxrys, 
| Plant Physiologist, Plant Physiological and Fermentation Investigations. 
\ 
| 
INTRODUCTION. 
A perfectly reliable method of destroying insects present in seeds 
imported into this country, without ijury to the seed, is much 
needed. The exclusion of insects by a careful selection of Popemamlky 
uninfested seeds at the port of export is impracticable, because many 
injurious insects pass their larval and pupal stages and a portion of the 
adult stage inclosed within the seed and on ‘The account might easily 
escape notice when the seeds were inspected. Furthermore, seeds are 
frequently received from localities where injurious insects are not well 
recognized, and, also, insects which are only slightly injurious in their 
native habitats occasionally become destructive pests when estab- 
lished in this country. 
The ordinary methods of destroying insects in stored seeds, such 
as subjecting them to heat (with or without moisture), carbon 
bisulphid, and hydrocyanic acid in the presence of air, have been 
tried and found unsatisfactory for this purpose. 
It occurred to the writers to create a partial vacuum in the con- 
tainer in. which the seeds had been placed and fill the chamber with 
some gaseous insecticide, such as carbon bisulphid or hydrocyanic 
acid, in the belief that a much larger amount of gas might thus be 
forced into the crevices of the seeds and into the insect galleries than 
would be possible if the entrance of the gas were dependent upon 
diffusion under normal atmospheric pressure. This method was suc- 
cessfully used with a number of different kinds of seeds and insects, 
and a convenient chamber, described later, was devised for fumigation 
under reduced pressure. 
1This work was carried on in cooperation between the Federal Horticultural Board and the Office of 
Plant Physiological and Fermentation Investigations, Bureau of Piant Industry, U. 8. Department of 
Agriculture. 
75871°—Bull. 186—15 
