DISEASES OF PLANTS. 255 



f<7).— Tlie repults of 3 years' olxservation on the use of formalin as a means for the 

 prevention of oat smut are given. In the investigations c^onsiderable variation was 

 found in the content of formalin as sold by chemical supply firms. The variation 

 consisted not only of differences in quantity, but in the specific gravity of the solution. 

 In the experiments the different strengths of solution -were reduced so as to be com- 

 parable. Comparisons were made between hot water and formalin for the preven- 

 tion of oat snnit, in which the hot water proved entirely efiicient, seed treated 10 

 minutes at 185° F. being wholly without smut, while those soaked in formalin solu- 

 tions showed a few smutted plants. The etficiency of the formalin was thoroughly 

 established, and the ease with which it may be applied renders it preferable to the 

 hot-water treatment. The effect of sprinkling or soaking the .seed was tested. The 

 seed which was sprinkled was spread on a floor and thoroughly moistened with 

 formalin solution. The effect of this treatment was compared with seed soaked for 

 from i to 4 hours, the sprinkling method being found less efficient. The compara- 

 tive value of formalin purchased in bulk and that which is put on the market in 

 pomid bottles was tested, in which no material difference was found in the two kinds 

 of formalin used. Apparently the cheaper formalin was just as efficient as the more 

 costly article purchased in the makers' bottles. In the course of the investigations 

 the effect of thorough screening of seed for smut prevention was tested, in which a 

 portion of badly smutted seed was thoroughly screened and passed through a famiing 

 mill and then seeded, which gave a decrease of 17 per cent in the amount of smut in 

 the crop. The influence of formalin on the yield of grain showed some remarkable 

 results in the crop of 1899. The gains on the plats in which the seed had been 

 soaked in formalin solutions varied from 26 to 86 per cent over the yield obtained on 

 the check plats. The experiments were repeated in 1900, and while there was an 

 increase noted for the treated seed, it was less than that reported for the previous 

 year. The resistance of the smut spores to formalin and hot water was tested, with 

 results already noted (E. S. E.., 12, p. 768). It is shown that the smut spores are 

 less resistant than grain, and that the solution continues to act upon the spores as 

 long as the seed is wet. 



The author recommends the use of a 1:60 formalin solution in which seed is soaked 

 from 1 to 2 hours, or J hour soaking in a 1:45 solution. If the seed is sprinkled a 

 1 : 45 solution is«recommended and the seed should be covered from 2 to 4 hours. As 

 this strength of solution is slightly injurious to the germination of the seed, a 

 greater amount of seed should be sown. The cost of treatment is said to be If cts. 

 per bushel. The practical advantage obtained from treating seed oats with formalin 

 varies from $1.60 to S4.20 i)er acre, as shown by the author's experiments. 

 ■ The prevention of oat smut, E. S. Goff ( Wisconsin Sta. Spec. Bui., Mar., 1901, 

 pj>. 4, fiys. 1). — A popular description is given of oat smut, the amount of injury 

 caused by the fungus, and methods of prevention. The principal means suggested 

 is the use of formaldehyde in which it is recommended that the seed be soaked or 

 sprinkled with 1 lb. of formalin to 45 gal. of water. The cost of the treatment of the 

 seed oats for 25 acres is placed at $1.20, and the increased yield due to the lack of 

 smut would give a net profit of §11.80. 



The value of formaldehyde for the prevention of potato scab and directions for its 

 use are also mentioned. 



Formalin and Massel powder as preventives of smut in oats and barley, 

 W. Saunders {Cannda Expt. Farms Rj^ts. 1900, p. 12).— O&ia and barley were treated 

 with a solution of formalin for different lengths of time, and with a fungicide known 

 as Massel powder. In every case the amount of disease in the treated plats was less 

 than in those plats the seed of which had not been given any treatment, but there 

 was little i)reference as to the method of treatment. 



Experiments to prevent smut in oats and barley, K. Rouektson {Canada Expt. 

 Farnu Iij>ls. 1900, pp.^SS-^So). — A report is given of experiments in which formalin 



834T— No. 3—01 :> 



