MiisJcmelon, Oats. 315 



been found upon squashes, melons, cucumbers, and pumpkins, in 

 some cases inflicting serious damage. It bears a certain resem- 

 blance to the downy mildew of grapes in its external charac- 

 ters. Affected parts of the leaves turn yellow, then brown, 

 while underneath these parts may be found the frost-like 

 patches so characteristic of the downy mildews. But with the 

 cucumber mildew the growth changes to a color closely 

 approaching violet. The dead leaf tissue soon becomes 

 broken, and the leaf is often entirely destroyed. 



Treatment. The application of a good fungicide, as already 

 described under downy mildew of the grape, should protect the 

 vines from the fungus. 



INSECT ENEMIES. 



See under CUCUMBER. 



OATS. 



FUNGOUS DISEASES. 



Loose Smut (Ustilago Acence, Jensen). Description. This 

 fungus causes the grains, and generally the husks as well, 

 to be transformed into a black mass in which all the normal 

 tissue of the oat plant has disappeared. This powdery mass 

 consists of spores. These appear when the crop is heading, 

 and they mature at blossoming time. When the crop is 

 harvested the spores have nearly all been blown away, leaving 

 a naked stalk. 



Treatment. 1 "It has been found that the infection of the 

 plant takes place when the seed is germinating and from spores 

 adhering to the seed when planted. If these adhering spores 

 can be killed, a crop wholly free from smut can be obtained. 2 



" The Jensen or hot-water treatment for oat and wheat smut. This 

 method, discovered by J. L. Jensen, of Denmark, in 1887, con- 

 sists in immersing the seed which is supposed to be infected 

 with smut for a few minutes in scalding water. The tempera- 

 ture must be such as to kill the smut spores, and the immersion 



1 The remedies here mentioned have been taken from farmers' 1 Bull. No. 5, of 

 the U. 8. Dept. of Agric. Div. of Veg. Path. 



2 "There is some good evidence to show that fresh manure of herbivorous animals 

 containing smut spores may, if applied at the time of planting, infect the young 

 plants. It is hardly necessary to mention this manner of infection, since almost no 

 American farmers manure grain fields in this manner. There is no danger in using 

 well-rotted manure." 



