220 TRANSACTIONS OF THE ILLINOIS 



is the more danger to the debilitated party. In damp, dark weather, 

 unfavorable to general vegetation, but well suited to fungous growth, the 

 latter has the advantage, and is not slow, as is well known, to improve 

 the opportunity. Subject to some of the varying conditions referred to 

 in the first part of this paper, the following are examples of diseases pro- 

 duced by fungous plants. In these cases, as in hosts of others, it can be 

 readily demonstrated that the parasites are the cause, not simply the 

 accompaniments, of the injury. 



Bunt or Stnut in WJieat, showing itself in the grain, and reducing 

 the whole interior to a black, pasty, or powdery mass. This is caused by 

 the spores of Tilletia caries being sown with the seed, and though not 

 showing its effects, the plant really grows with the wheat from the begin- 

 ning. The practice of washing the seed in brine, and afterwards drying 

 it with lime, is an almost effectual preventive. Simple washing with 

 water, or thoroughly blowing in the windmill, must aid. Rust of the 

 stems and leaves of small grains generally, but of wheat especially, is due 

 to Puccinia graminis, whose spores form the rusty powder, which is some- 

 times so abundant about^harvest time, staining the workmen's clothing. 

 Another kind of spores are afterward produced, which are nearly black. 

 These last stick to the straw during the winter, and doubtless constitute 

 the germs of the next year's generation. Washing the seed can do no 

 good in this case, while carefully carrying away the straw, burning the 

 stubble, and cleaning the corners of fences, etc., of all grass-like produc- 

 tions, may prevent the attack. The full history of this parasite has not 

 been made out, but every farmer must have noticed that its growth de- 

 pends very largely upon the weather. Hot sunshine, broken at intervals 

 by showers of rain, load the air with vapor, rendering the atmosphere 

 "muggy" and unsuited to ordinary vegetable growth, but well adapted 

 to the Puccinia, which quickly destroys the crop. It was present before, 

 but not active enough to become very injurious. 



The Rot of stone fruits, causing them to shrivel upon the tree, and 

 soon covering them with a gray mass of dust, is the sure result of Oidium 

 (Torula) fructigenum. Any one may satisfy himself as to the action of 

 this fungus by simply wetting or puncturing slightly the surface of a 

 healthy fruit, and placing upon it some of the dust from an affected peach. 

 The experiment is almost sure to suceed, though occasionally, in dry, 

 clear weather, it may miss. Examining with the miscroscope, twenty- 

 four hours after the sowing, the substance of the fruit, the threads of the 

 fungus will be found in abundance, and in two more days the unaided 

 eye easily detects the mischievous work. Theoretically and practically 

 the prevention of this disease is to ward off, as far as possible, the insects 

 which puncture the fruit, and to remove cautiously every rotting one as 

 soon as discovered. These may be buried in the ground or burned. 



The Fire Blight of the pear needs more study, but the Leaf Blight of 

 pear seedlings certainly, and large trees probably, is from a fungus whose 

 name is unknown to me, but which is similar in habit to the puccinia 

 above mentioned. Beyond what is commonly known, however, there is 

 no certain remedy. These pear diseases shall receive attention hereafter. 



