216 



DISEASES AND ENEMIES OF GROWING PLANTS. 



causes both to dissolve readily in water. This is sufficient 

 for a barrel of water, and when used may be filled up 

 again. It may be applied with a syringe or sprinkling 

 pot to the foliage of affected plants. Sulphur vapor is also 

 a certain remedy for mildew for plants or vines under glass. 

 760. The wheat mildew is very different in its nature 

 from that found on trees or vines, which may be called 

 the white mildew, though its effects are somewhat similar. 



761. The white varieties of wheat appear to 

 be more liable to the mildew than the red or 

 spring varieties, and the bald more than the 

 bearded. The most vigorous plants are most 

 frequently attacked and suffer the most, and 

 the disease is more destructive to plants which 

 are headed out than to younger ones. Figure 

 41 shows the appearance of an car of ripe wheat 

 covered with mildew. 



762. After the spots of wheat mildew have 

 extended over the whole plant, they assume a 

 rusty color, and throw off a fine dust which is 

 yellowish at first, but soon turns brown and 



Flg 41&amp;lt; rusty by exposure. Hence the disease often 

 goes by the name of rust. 



768. Wheat growing on low, undraincd lands, with a 

 peaty or calcareous soil, is most liable to be attacked by 

 mildew, but this disease often appears on sandy soils and 

 on the stiffest clays, especially when a few days of damp, 

 i oooy -weather, are followed by a hot sunshine. 



7&amp;lt;il. No remedy is known which can be relied on to 

 protect against this mildew, but the free use of sail or 

 saline manures, soaking the seed in brine, or sprinkling 

 the plants with salt dissolved in water at the rate of half 

 a pound to the gallon, are the most effectual. 



