ERGOT.

Globe, Volume XXIII, Issue 2140, 4 January 1881, Page 3

ERGOT.

[From the “ Weekly Pres*.”] This fungal disease, scientifically known as clavicept purpurea, is one grsatly dreaded by English agriculturists, and in this new and healthy country farmers are not free from its evil effects. It has been tho object of much attention from scientific men during the last

1250 yean, but it was not till quite recently, leas than ten years ago, that the true nature of the disease was discovered. The honor of tracing out the life history of the fungus belongs to that most patient and talented naturalist, M. Tulasne. So little was understood of the true nature of ergot that within a comparatively recent period even the fungal character of the discano was disputed. Like rust, the disease passes through several welldefined stages, and each phase has apparently so little connection with the others that they were formerly supposed to constitute distinct organisms. A peculiarity of ergot is that its destructive effects are exerted entirely on the ovary, or young fruit of the infected plant. In tracing out the life history of the pest, scientific terms cannot entirely be avoided, but we shall endeavor to mate the matter as clear as possible to the general reader. Ergot is one of the most dangerous of farmers’ enemies, and it is therefore desirable that its nature should be understood, this being a first and very important step towards effecting a remedy. This disease first manifests itself by the young ovary, that is to say, the first differentiated stage of the future grain, becoming covered here and there with slender microscopic spores which speedily germinate, piercing and destroying the internal tissue, while on the exterior of the affected grain there are formed a large number of oonidia, or dust, spores. These are accompanied by a mucilaginous secretion over the entire ovary called honey-dew. The conidia becoming easily detached from the gummy exudation and falling on the flower of neighboring healthy plants at once germinate and give rise to new mycelia, or filaments, from which the disease is developed, and thus

the disease is spread in every time the mycelium pervades the entire tissue of the ovary, and a hard mass is formed similar in shape, but much larger than the normal grain or seed. This hard substance, called the solerotium, is of & dark purple color, and its appearance, especially in ryegrass, is probably familiar to most agriculturists. By the time that the ergot is fully formed, the sphaeelia, or gummy secretion before alluded to, will have disappeared, or only the withered and dried up remains of it are visible at the apex of the aclerotium. Towards the end of autumn the ergot falls to the ground, perhaps remaining there undisturbed through the winter. In the following spring it developes from its surface a number of slender stalks, each of which is surmounted by a single or double globular head, known as sphisria. The surface of each spbeeria is dotted with minute elevations, which are tubelike entrances to little chambers called perithecia, which are very numerous and embedded in the superficial tissue of the spbteria. To the base of each perithecium there is attached a large number of filamentous structures, which lie parallel to each other and extend along the cavity of the perithecium, with their free ends underneoth the aperture which communicates with the exterior of the spheoria. These are the aacospores ; they are much longer than broad, and are somewhat spindle shaped. They are ripe at about the time the cereals come into flower, and by the action of the atmosphere they obtain access to the flowers and germinate on the ovary. This, then, is the life history of the fungus, and now we may proceed to touch upon the possible measures for prevention, and also upon the effect produced by ergot on the animal organism. Rye is more frequently attacked by ergot than any other cereal, but it is found occasionally in wheat and barley. Of the cultivated grasses, those most usually ergoted are rye grass, fox tail, timothy, tall fescue, mamma grass, and cocksfoot. Some of the native grasses of New Zealand are also liable to be affected by the disease. The ergot is always most plentiful after a wet summer, and is generally found in special abundance in grasses growing in damp and neglected ditches. These places should be mown and the grass burnt, for by allowing ergotised bents to stand through the winter the perpetuation of the disease in the following spring is rendered certain. It is only during the autumn that any material check can be applied to the claviceps purpurea. By destroying the sclerotium, or mature ergot, the chain which makes up the life cycle of the fungus is broken. To utterly eradicate it is impossible, but every infected bent which is destroyed lessens the number of centres of contagion. With regard to the effects produced by ergot, a groat authority on “poisons” states that ergot administered in a large dose in any form is liable to cause dryness and irritation of the throat, salivation, thirst, burning pain in the stomach, vomiting cholic, and sometimes diarrhoea. It is used in veterinary medicines to arrest certain btsmorrbages, and to assist in difficult cases of parturition. Ergot inadvertently eaten by mares in foal ond cows in calf is very opt to produce abortion ; many valuable beasts having been lost in this way. Not long since a case was recorded in a Homo paper relating to a flock of sheep which became every autumn affected with foot-rot, although the pasture on which the sheep were fed was a dry one. The case was most puzzling, but scientific investigation eventually proved that the outbreak of the foot rot was induced by the culms of the pasture becoming ergoted every year ; and if the bents had been mown and removed in the autumn the loss would have been prevented. The presence of ergot in flour has also been known to causa serious diseases in the human species.