342 Tin-: farmers' handbook. 



to mature heads, and on drying out, the flag, nowcurled and abnormally grey, 

 gives rise when crushed to a fine, soot)-, black dust. This dust consists of the 

 spores of the Flag Smut fungus (Urocystis tritici.) 



During the harvesting operations these diseased plants arc knocked about, 

 and the fine sooty dust is distributed through the soil, often, too, adhering to 

 otherwise healthy grain. If the young wheat plant at the time of germination 

 be-in contact with spores of the Flag Smut which may be lying in the soil, it 

 is liable to become diseased. If, as sometimes happens, the land is otherwise 

 tree from the disease and the spores happen to be adhering to the grain, 

 infection is again probable. 



The control of this disease on the farm is difficult. The greatest danger 

 lies in allowing the soil to become thoroughly infested with the spores of the 

 smut. Pickling will help to prevent the infection of new land. 



Rotation of crops is very desirable, as this parasite is not known to attack 

 other hosts. The introduction of an oat crop and of a bare fallow period 

 into the farm rotation is possible, and a!so profitable in most of our wheat 

 districts. 



Early preparation of the seed-bed is recommended, because it assists in 

 the conservation of moisture, and in the germination of Flag Smut spores 

 prior to the sowing of the wheat. The opinion that Flag Smut is worse with 

 a dry sowing is very generally held, and there is a good deal of experimental 

 evidence to support this idea. It seems probable that under such conditions 

 the spores of the fungus remain with the wheat ungerminated until rain 

 provides the necessary moisture, and that the parasite and host then 

 germinate together, and infection results. 



If wheat must follow wheat, then the land should be ploughed as early 

 as possible after the harvest, and thoroughly worked during the short fallow 

 period with a view to providing a seed-bed with adequate moisture. 

 Rapidity of germination gives the wheat a chance to escape its parasite. 



Burning off of a crop which is badly affect°d is sound practice. An effort 

 should be made to secure a very thorough burn of the diseased portions 

 of the crop, so that isolated patches of the diseased straw do not escape 

 the fire. 



Seed harvested from an infected crop should not be sown without pickling. 



Pickling the wheat in bluestone, as recommended for the prevention of 

 Bunt or Stinking Smut, can also be recommended for this disease. 



McAlpine has shown that the spores of this Smut can pass uninjured 

 through animals, and so stock fed on diseased hay or straw can convey the 

 infection to otherwise clean paddocks, or reinfect a renovated fallow. 



Wheat Rusts {Puccinia graminis and P. triticiiia). 



There are only two kinds of wheat rusts in Australia — the positively in- 

 jurious Puccinia graminis and the comparatively harmless Puccinia triti- 

 cina; this latter does not cause the grain to shrivel like the former. In 

 the following notes when speaking of Rust, Puccinia, graminis is referred 

 to. 



Warm weather, with frequent showers and heavy dews, favours the 

 development of Rust. Wheat, the straw of which is badly rusted, fails to 

 develop the grain properly. The presence of the Rust appears to prevent 

 the food material elaborated by the plant being transferred to the grain, 

 which, in consequence, remains small and pinched. Affected wheat does 

 not appear to lose any of its nutritive qualities when chaffed, and when 

 fed to horses and cattle is often greatly relished. Growing on wheat. Rust 



