Wheat Rust in Australia. 65 



But the effect upon the composition of the plant, and particularly its 

 feeding value, is not known to the farmer, who cuts his crop for hay when 

 rust threatens to ruin it. 



This has recently been determined by F. T. Shutt l , chemist, Dominion 

 Experimental Farms, Canada, who analyzed two samples of wheat grown 

 at Manitoba in the same field and of the same age, only the one was rusted 

 and the other rust free, so sthat the results are strictly comparable. The 

 analysis is as follows: 



ANALYSIS or RUSTED AND RUST-FREE WHEAT-STRAW AND GRAIN. 



The Straw. It is pointed out that in crude protein the rusted straw is 

 much richer, and since this includes all the nitrogenous compounds of a food 

 that go to repair waste, form blood and build up muscle, it may safely be 

 concluded that the rusted straw is much superior in feeding value. There 

 is also in the rusted straw slightly more fat and somewhat less fibre, so 

 that all this affords additional evidence of its more highly nutritious nature. 



The handling and feeding of rusty straw in Australia from the farmer's 

 point of view has received attention. The experience of one who has done 

 a deal of threshing is to the effect that when very bad it caused an itchy 

 sensation, and made the men about the thresher rub their skin until it was 

 broken. As regards feeding rusty hay, another with large experience 

 informs me that horses and cattle relish it far before ordinary hay. Of 

 course, it was fed as chaff. 



The Grain. This from the rusted wheat is only about one-half the 

 weight of that from the rust- free wheat, but as the protein content shows, 

 it has, weight for weight, a considerably higher nutritive value. He 

 accounts for the higher protein content in the smaller grain in its larger pro- 

 portion of bran, but chiefly in the partial and incomplete transference and 

 accumulation of starch. 



These results likewise afford interesting evidence as to the physiological 

 effect of the rust on the wheat plant, and agree with what has been deduced 

 from other data. 



In the actively growing and feeding period of the plant's life, it is 

 apparently able to provide for the wants of the fungus as well as its own, 

 and therefore its vitality is not seriously affected. But when the second 

 period of forming and ripening the seed arrives, when feeding is gradually 

 ceasing, and the accumulated materials are being transferred to the seed, 

 then the fungus draws upon the plant's capital, crippling its energies, and 

 checking the movement of the food materials to the seed. As Shutt sum- 

 marizes the whole process: " The growth of the rust arrests development, 

 and indicates premature ripeness, which, as we have seen, means a straw 

 in which still remains the elaborated food, and a grain small, immature, 

 rich in protein and deficient in starch." 



This emphasizes what we have frequently insisted on, that the critical 

 period, literally the turning point in the plant's life, is reached when it 



