44 



THE GENESEE FARMER. 



Feb. 



PARASITIC FUNGI OF THE FARM— No. 2. 



Figures 4 and 5, in the January number of this 

 journal, represent the most common variety of mil- 

 dew, tiie botanical name of which is Puccinia Grain- 

 inis. The minute fungus that attacks the joints of 

 wheat, is called dinpnzca, and not diapaza, as printed 

 in our last. One of the most common kinds of mil- 

 dew in this country is the black fungus, which gives 

 a dark sooty color to whole wheat fields, towards 

 harvest. It is said by those who have made this 

 class of plants a particular study, that this fungus 

 never attacks sound, healthy plants. It has no pop- 

 ular name ; it is called by botanists, Cladosporium 



Herbarvm. Fig. 6 shows it to be quite unlike com- 

 mon mildew ; and it grows on old leather as readily 

 as on wheat. Its spores (seeds) may be seen in fig. 

 6, in their cases. The common appearance of straw 



Fig. 7. 



affected by this parasite, is shown in fig. 7. What- 

 ever preserves the health of wheat, is a preventive 

 of this malady. 



Wo now come to fungi called Urcdinc^, plural of 

 vrcdo, and derived from the Latin w/-o, to burn. — 

 There are several varieties of this fungus; the most 

 common are urcdo rubigo, (tig. 8,) or red rust, urtdo 

 scgetum, and urcdo fetida, (fig. 9,) or fetid smut. 

 The two last take the place of seeds in the heads of 

 wheat. Maize or Indian corn is subject to attacks 

 from these parasites, as well as barley and oats. 



Fio. 8 



" Rust," from its resemblance to the red oxide of iron, 

 has often been attributed to an excess of that mineral 

 in the soil. In England it is variously denominated 



"rerf rohhi,^' "rcd-i-ag,^' and "red-gum." Damp, 

 warm weather favors the growth of this fungus ; and 

 its spores multiply with astonishing rapidity. Fig. 

 8 represents the spores of red rust as they appear 

 under a microscope of great power. The mycelium 

 on which these spores grow, finds its matrix in the 

 tissues of the plant. If the cuticle or outer covering 

 of its stem is well filled with flint, (silica,) it serves 

 to protect the plant, in a good degree, from being 

 "struck with rust." One sometimes meets with 

 wlieat and rye straw as hard nearly as glass, and lit- 

 erally cased in a vitrious coat of mail. No urcdo 

 can flourish in so sterile a soil. To produce a bright 

 straw to wheat, see that the ground is not too wet, 

 nor full of grass or weeds ; till thoroughly, and use 

 lime, salt, or ashes freely, at the time of seeding, or 

 in the spring. Potash, soda, and lime, operate to 

 increase the solubility of fine siliceous sand, of which 

 the ash of wheat straw should contain about ()8 per 

 cent. Clean culture, a reasonably dry soil, and a 

 plenty of alkalies in it, are the best preventives of 

 rust. 



There are two common varieties of " smut." One 

 is the uredo segctum, and the other urcdo fetida, 

 (fig. 9.) The spores of both are found in the cov- 

 ering of seeds, and seem to be grown at the expense 

 of elements designed by nature to form starch and 

 gluten, if the parasite did not attack the cereal. The 

 seeds of smut {uredo segetu7n,) are found, by the 

 measurement of a micrometer, to be only the two 

 thousandth part of an inch in diameter. Although 

 very undesirable in flour, this uredo is less offensive 

 than the fetid variety, which is more oily, and has 



F.G. 0. 



the appearance shown in fig. 9, under a good micro- 

 scope. Its spores are much larger than those last 

 named, being the six hundredth part of an inch. 

 Most grasses are subject to this parasite, which de- 

 stroys their seeds, as all observers of natural phe- 

 nomena have seen wheat aborted by this malady. 



Moses threatened the disobedient Israelites with 

 mildew, and the Romans had their false god Ihibigo, 

 whom they thought to propitiate for the preservation 

 of their grain from the disastrous attacks of these 

 parasites. A feast called Robigalia, to this deity, 

 was always kept on the 25th of April, to deprecate 

 blasting and mildew. American farmers do not cel- 

 ebrate the feast Robigalia, but they show great 

 reluctance to encourage the critical study of the 

 causes that destroy so many millions of bushpls of 

 their grain. If a single dollar has ever been expen- 

 ded in these United States, by Congress, a State 

 Legislature, or any agricultural society, to investi- 

 gate the i;ature of mildew, rust, or smut of any kind, 

 ♦he fact has wholly escaped our reading. 



For many years the Berberry \\&s thought to pro- 

 duce mildew and rust on grain. At length it was 



I 



^14^^ 



