18 BOARD OF AGRICULTURE. 



much damage when it extensively aflFects the plant in the later stages of its 

 growth. The deposition-on the leaves and stem is red, or dusty iron color, as 

 if a rusty powder were sprinkled over them. It is a disease of the respiratory 

 organs in the course ot which according to botanists, two fungi of the genus 

 uredo infest the plant, one termed uredo ruhigo, wlicn the seed spores are 

 spherical, and uredo linearis, when they are oblong. They are fully illus- 

 trated in the Secretary's Report for 1858, page 142, &c. 



Rust prevails more in the fields where crops of wheat have been raised for 

 several years in succession. Thin crops are more liable. It aflects other 

 grains, and some wild plants. The causes and remedies are the same as those 

 mentioned for mildew. 



Rye is subject to a disease in which the young grain becomes white and 

 then black. It is called ergot, a French word signifying cock's spur, on ac- 

 count of the peculiar curved form the affected grain assumes. It also some- 

 times attacks certain grasses, wheat and barley. Almost every variety of 

 plant lias some particular soil in which it thrives best, and if not situated in 

 thiit favorable soil it is liable to disease, because it cannot assimilate or con- 

 vert food into its own peculiar structure. Thus rye will not succeed well in 

 heavy or damp clay soils, especially in wet seasons. It cannot derive from 

 them suitable nutriment. Its vitality is impaired. It becomes sickly and 

 ergot is the result. From throe to ten grains in the spike are affected, the 

 rest may be healthy. The spur varies in length from a few lines to two 

 inches, is cylindrical, colored black externally with streaks of gray. The 

 deformed kernel is infested by a parasitical fungus from its earliest develop- 

 ment, which can be detected by the microscope, and this reproductive seminal 

 dust taken from its surface will engender the disease in other predisposed 

 plants if scattered in the soil near their roots, or applied directly to the grow- 

 ing grains. 



Rye meal containing much ergot, produces a disgusting and fatal gangre- 

 nous disease among mankind in districts where it abounds. Ergot may be 

 avoided by sowing rye in light or sandy soils, and using seed from crops which 

 have not been infected. 



There are two varieties of smut, one termed black ears principally affects 

 oats and barley in warm damp seasons. It occurs when the ears shoot out of 

 their sheaths, generally attacking only a few kernels, but sometimes extends 

 to the whole ear and the leaves and stems. The young ears become coated 

 with a black substance, which at maturity resembles lamp black and is scat- 

 tered profusely by the winds before the grain is harvested. This powder, by 

 the use of powerful microscopes is found to be the seeds of a very minute 

 fungus called uredo segetum so exceedingly small that it is estimated it would 

 require eight millions to cover one square inch. 



The other kind, or smut ball, is a disease of wheat in which the whole 

 interior of the kernels of more or less of the grain is converted into a dark, 

 greasy powder, witli a disiigreeal)le smell. It occurs in the inner cavity of 

 tlie forming kernel during its earliest stage, jierverting its nutrition, changing, 

 its whole ciiuraeter and quality, and constituting a nest for the growth of 

 myriads of infinitesimal mushrooms of the species, uredo fyeteda. These are 

 conveyed into the ground with the seeis, are absorbed by tlie roots in t'le pro- 

 cess of germination, and ascend with the sap. The morbid kernels continue 

 to enlarge and mature, and are gathered unbroken with the sound grain. But 

 when it is tlireshed, these diseased kerneh are bruised and ruptured. They 

 emit their peculiar odor; and the KrcMsy powder escapes and adiieres tena- 

 ciously to the surrounding wheat. It lias been ascertained by long trial, that 

 i( the tainted seed be cleansed, tlie plants generally will not be infected. 

 Hence, the practice extensively prevails of soaking the wheat in some solution 

 which will destroy the fungus, but will not affect the germinating power of 

 the grain. Alkaline washes are the best and most efficient, because they com- 

 bine with the oily matter, and convert it into soap. Among these are lime 



