Oats, Onion. 319 



ment, especially in case of stinking smut of wheat. If the seed 

 is to be sown broadcast it will not have to be so dry as if it is 

 to be drilled. The seed may be treated with hot water a con- 

 siderable time before planting if dried carefully, but it is prob- 

 ably better to treat just before planting." 



Rusts. The various rusts which attack oats, wheat, and 

 barley have not been successfully treated by the use of fun- 

 gicides. 



ONION. 



FUNGOUS DISEASES. 



Mildew ; Rust (Peronospora Schleideniana, Unger). Descrip- 

 tion. Seed onions, especially when grown on low ground, ap- 

 pear to be particularly affected by this disease. The first 

 appearance of the trouble is the formation upon the onion tops 

 of a grayish velvety coating. The leaf wilts, and turns yellow. 

 This occurs about the time that the onions begin to bottom. 

 The fungus passes the winter by means of spores which are 

 developed within the tissue of the host-plant. 



Treatment. Proper applications of the Bordeaux mixture, or 

 of some other fungicide, if made early in the season and re- 

 peated at intervals of two weeks, should keep the disease in 

 check. All affected onions should be destroyed. 



Smut (Urocystis Cepulce, Frost). Description. The disease 

 is more severe upon dry land, as the onions appear to be less 

 able to outgrow it. The first leaves of the seedlings are 

 attacked, dark spots scattered along their surfaces showing the 

 presence of the fungus. Such plants generally die before the 

 third leaf is formed. When the disease appears upon older 

 plants the bulbs show dark ridges extending up and down 

 their sides, even to the leaves. These ridges are mainly com- 

 posed of a sooty powder consisting of the spores of the fungus. 

 It has been estimated that a single large onion may mature 

 a cubic inch of smut in a single season. The soil soon becomes 

 rilled with the germs of the disease, and it is almost impossible 

 to grow a sound crop. 



Treatment. Affected soil should not be planted to seed 

 onions. It appears probable that by transplanting onions the 

 disease may be largely avoided, since it enters the young onions 

 before they appear above ground. One ounce of a mixture of 



