Flag Siiinf of Wheat. 93 



Jade, Comeback, Federation, and Bunyip. There was a little flag smut in 

 each plot, but it was confined to a few plants, and the yield in no case was 

 seriously affected. 



At Longerenong there were also ten plots of selected wheats of 1 acre each. 

 The fla^ smut was not so much in evidence, but there was a little of it in the 

 four varieties — Australian Talavera, Dart's Imperial, Jade, and Federa- 

 tion. 



Nature of Fungus causing Disease. 



The flag smut of wheat belongs to the genus known as TJrocystis, because 

 the spores are provided with bladder-like appendages which in this case 

 completely envelop them, and thus act as a protective covering. The spores 

 are produced in long streaks on the flag, which soon curls up and withers, and 

 thus the smutted portions of the plant become mixed with the soil under 

 favorable conditions for the spores attacking the succeeding crop of w^heat. 

 As will be shown afterwards, they infect the plant at the seedling stage, or 

 when the young shoots are formed, and generally destroy the entire stool, 

 although sometimes a few ears may come to perfection beside those stalks 

 which have withered and died. The dissemination of the spores is well pro- 

 vided for in nature by mixing with the soil, and the withered shreds and patches 

 being blown about by the wind. Men and animals are also unconscious 

 agents, not only in transporting the smutted earth from one field to another, 

 but the agricultural implements may also carry it to otherwise clean fields. 

 It can also be readily distributed by means of chaff and horse or cattle drop- 

 pings. On examining 42 commercial samples of wheaten chaff from various 

 parts of the State, only one was found free from the spores of this smut, and 

 some of them were exceedingly bad with it. The disease was exceedingly bad 

 in two cases, very bad in seven, bad in ten, common in thirteen, slight in eight, 

 and very slight in one. Owing to the nature of the disease, the microscopical 

 examination of chaff samples furnishes a very accurate guide as to the pre- 

 sence or absence of the disease in any particular district. 



Geographical Distribution. 



Although an allied species of smut is well known on rye in both Europe 

 and America, the species on wheat is unknown there. It was first found in 

 Australia, and since then it has been met with in India and Japan, and that 

 is the extent of its distribution as known at present. 



It is very widely distributed in South Australia, where wheat has 

 been so lon^ and so extensively grown, and in Victoria it is now 

 more or less prevalent in the northern areas. In New South Wales it is 

 probably more generally distributed than it is supposed to be, and in Queens- 

 land it has only been recently discovered. 



Once this disease has gained a footing in a district there is every likelihood 

 of it spreading if not kept in check, for it can be carried about by the farm 

 implements and in the soil from diseased fields, and even in the manure from 

 horses and cattle fed on the diseased hay. 



Germination. 

 The germination of this smut was specially studied, because the spores on 

 diseased straw in the soil, as well as those on the grain, were capable of in- 

 fecting the young seedling. It has been tested for a period extending over 

 three years, with spores of various ages, and at different seasons, in order to 

 determine the period of its greatest activity. The most luxuriant germination 

 was obtained about the beginning of April (autumn), and it is during the 

 autumn months that the wheat is generally sown. The. results of various 

 germination tests will now be given. Spores were taken from the wheat-plant 



