DISEASES CONNECTED WITH TEED 311 



The risk which one takes in feeding any foodstuff which 

 has kept badly depends upon the extent to which deterioration 

 has taken place. The degree to which the food is damaged 

 may range from a faint moldy smell to a decomposing and 

 offensive-smelling material. 



Root-crops, under the conditions usually kept, may readily 

 undergo decay. Rotten potatoes and other roots may produce 

 digestive irritation and even poisoning. 



Cleanliness in feeding is essential. 



Baby chicks sometimes gorge themselves with sand, impac- 

 tion of the crop being the result, and death often follows. 



DISEASES OF FEED 



Certain fungi attack plants during growth, and thus may 

 be considered parasites of that plant. 



Those organisms which attack the grain or plant after death 

 or at maturity are called saprophytes. 



Some organisms attacking foodstuffs are vegetable in nature, 

 while others are animal organisms. 



The organisms here considered destroy the grain on which 

 they live. 



The principal vegetable parasites are those causing ergot, 

 rust, smut, and mildew. (See Fig. 104, i, j, and k.) 



Those attacking plants and grain after death or at maturity 

 cause moldiness and rottenness, and these molds belong to 

 the genera of aspergillus, penicillium, and mucor, besides 

 many kinds of saprophytic bacteria. (See Fig. 104, a, b, c, and 

 d.) 



Puccinia graminis is the fungus which under certain condi- 

 tions attacks growing grain. It must necessarily pass through 

 two hosts or plants to complete its hfe cycle. In each host 

 it produces a distinct disease. The stems and leaves of all 

 grasses and cereals may be attacked by it in the early summer. 

 On these it produces yellowish-red lines or spots. The color 

 is due to the spores or seeds of the fungus. This material 

 when dry is dust-hke, and gives the rusty appearance to the 

 leaf or stalk attacked. The mycelia or mass of hyphse are 

 composed of elongated cells, arranged end to end, and grow 



