April 15. I9I9 • Seed Disinfection by Formaldehyde Vapoi 



35 



The finely atomized formaldehyde solution thus enters the can and is 

 carried to all parts of it with the steam. Condensation takes place on 

 the surface of the seeds, forming a thin film of moisttire about each 

 seed in which the formaldehyde may act, and as this film evaporates the 

 gas is freed. 



A frame (E) containing three wire shelves was used inside the can, 

 and the seeds were placed in porcelain dishes ®n these shelves. 



EXPERIMENTS 



There are two distinct phases of this problem: (i) The effect on the 

 seeds and (2), the effect on the fungi and bacteria. 



Table I gives the result of a series of treatments of a number of differ- 

 ent seeds. The formaldehyde solution, before dilution, was used at the 

 rate of 10 ounces per 1,000 cubic feet to procure the results given in 

 the second, third, and fourth columns and for the time indicated. The 

 results given in the sixth column are for formaldehyde used at the rate 

 of 30 ounces per i ,000 cubic feet for 2 hours. 



The germination percentages given in this table are an average of the 

 results obtained by the Seed lyaboratories, Bureau of Plant Industry, 

 United States Department of Agriculture, from germinating two samples 

 of 100 seeds in each case. 



Table I. 



-Effect of formaldehyde vapor of different strengths for varying lengths of time 

 on the gcrminatioti of seed 



Seed. 



Alfalfa (C. I. 44)' 



Barley (C. I. 25)' 



Beet 



Carrot, Oxheart 



Clover, Crimson 



Com, Miner's Yellow Dent. . . 



Field Pea 



Flax 



Lettuce 



Millet 



Muskmelon, Rocky Ford. . . . 



Natal Grass 



Oats(C. I. 541-4)* 



Orchard Grass 



Radish, Icicle 



Rice(C. I. 1561)' 



Rye (C. I. 138)' 



Soy Bean 



Sudan Grass 



Wheat, Blue Stem (C. I. 1912- 



"V 



Checks. 



95-5 

 92-5 

 71-5 

 69- 5 

 70-5 

 96-5 

 93-5 

 94-5 

 97-5 

 94- S 

 87 



I- 5 

 98 



64- 5 



97 



93-5 



83-5 



95-5 



84 



57-5 



Strength formalin. 



Checks. 



96 

 90. 

 66 

 72. 

 69 

 97 

 93- 

 86 



99 



51-5 



95 



76. 

 96 

 93- 

 83 

 99 

 80 



62 



30 ounces 

 per 1,000 

 cubic feet 

 (3 hours). 



Per cent. 

 89-5 

 92.5 

 68.5 



79 

 64 



85 

 99 

 88. 



93- 

 o 



98 

 61. 

 96. 



95 

 86 



97- 

 84. 



61. S 



• These are accession numbers of the OfiSce of Cereal Investigations, Bureau of Plant Industry, U. S. 

 Department of .\griculture, from which some of the seeds were obtained. 



