Letters on the Diseases of Flants. 17 



inspection and again used for seed, this time producing (say) 50 acres of 

 wheat. Meanwhile the second stud plot had furnished another half bushel 

 or more of healthy seed, and a few extra good plants with which to start a 

 third stud plot. 



The continuance of this system (see Fig. 19), when once inaugurated, 

 insures a constant supply of healthy seed wheat of superior quality ; and of 

 the good results of the method, I wish to give farmers the most positive 

 assurance. 



Though the carrying out of this system with such a large number of wheats 

 as are handled at the Wagga and Bathurst Experiment Farms is somewhat 

 expensive, the extra cost is due solely to the strict and skilled supervision 

 that has to be exercised in order to insure accuracy in the work. With only 

 one or two varieties on an ordinary farm the method is a very simple one, 

 and one that should be very widely adopted. 



About three years are required to get this system of producing seed wheat 

 into good running order, after which it will give very little trouble, and pay 

 its way ten times over every year in the superiority of the resulting crops, 

 not only through their freedom from smut and other diseases, but in extra 

 yield and quality of the grain. 



There is, however, one factor in this method of wheat-growing that must 

 be watched, and that is the land on which the bulk of the wheat grows. If 

 this land is contaminated with bunt to begin with, bunt will continue to 

 appear in succeeding crops. This can be largely prevented by introducing a 

 change of crop, or by fallowing the land. 



For the full particulars of the method of treating the seed with hot water 

 and with bluestone I must refer the reader to Yol. II, p. 672, of this Gazette. 



6. Maize Smut. 



Formerly, when writing on maize smut, while suggesting treatment of the 

 seed with bluestone or hot water, I threw doubt on the efficacy of these 

 treatments, and strongly advised that, where small areas of maize were grown, 

 all smutted parts of the plants should be collected and burned, especially if 

 maize was to be sown again immediately on the same land. I did this from 

 life-long familiarity with this disease, and the failure, in my own case, of 

 any method of combating this disease, other than that of destroying the 

 smut as fast as it appeared. As, however, owing to the great similarity of 

 the maize smut-fungus to others which were known to enter the crop by way 

 of the seed, it seemed probable that maize-smut also attacked the seed, more 

 especially as this was already widely assumed to be the fact, I thought best 

 to give countenance in this journal to the treatment of the seed, as was the 

 custom in other pathological publications. Now, however. Dr. Brefeld, who 

 for many years has made a speciality of the smut-fungi, after long and careful 

 study, has come to the conclusion that maize first becomes infected with 

 smut after it is at least a foot high, and principally through the spores of 

 the fungus dropping into the " cone " formed by the latest well-developed 

 and topmost leaf. This important discovery is in full accordance, I believe, 

 with the experience of those who, like myself, have produced no satisfactory 

 results by treatment of the seed of maize that is grown in the ordinary way. 

 The full significance of this matter is not fully grasped until we realise that 

 Jienceforth we are relieved, so far as maize smut is concerned, from the 

 expense of treating tlie seed. This is no small item when considered in a 

 national light. 



