68 DISEASES OF TREES 



be directed to preventing the transference of smut-spores to the 

 field. To secure this, seed which is as clean as possible should 

 be used. If this cannot be had, the adhering spores should be 

 killed by steeping the seed-grain for twelve to sixteen hours in 

 a one-half per cent, solution of cupric sulphate. Further, the 

 use of smutted straw for manure should be avoided. 



The most important kinds of smut (brand) are : 



THE COAL-BRAND, STICKY-BRAND, STINK-BRAND, OR BUNT 

 of wheat ( Tilletia Caries and T. Icevis] which besides attacking 

 wheat is also found on quickens, wall barley, and meadow grass 

 (Poa pratensis] is characterized by the fact that the spore- 

 powder (which emits a disagreeable smell when fresh) remains 

 enclosed in the grains till the time of harvest. The bunted 

 grains being bruised in threshing liberate the spores, which 

 adhere to the sound grains, and, both being sown, the young 

 plants become infected. 



The DUST-BRAND (Ustilago] is the most destructive genus, 

 and also contains the greatest number of species. Ustilago 

 Carbo attacks not only oats, wheat, and barley, but also a large 

 number of meadow grasses. It completely destroys the ovary, 

 and usually the paleae as well, so that brown spore-powder 

 escapes on to the stalk. 



Ustilago destruens, the Millet-brand, destroys the panicles of 

 the millet while they are still enclosed by the highest leaf- 

 sheath. 



Ustilago Maydis, the Maize-brand, produces large swellings, 

 completely filled with dark brown spore-powder, on the stem, 

 leaves, and cobs of the maize. Numerous other species occur 

 on grasses, herbs, and bulbous-rooted plants. 



The STEM-BRAND (Urocystis} is frequently met with, and 

 especially the brand of rye-stems, Urocystis occulta. It is very 

 conspicuous, on account of the highest internode of the rye-stem 

 rupturing longitudinally, and allowing the black spore-powder 

 to escape. 



Other forms often met with are Urocystis Viola, U. Anemonis, 

 and U. Cepulce. 



