Common Names

Ergot of rye is generally known and spoken of as ergot; but occasionally in European literature, reference is found to "spur kernels," "blight kernels," and "spurred rye."

Description

Ergot is a form of a fungus parasitic on grasses, one of the best known species being that found on rye. The fungus is most easily recognized in the second stage of its development, when the hard, dark purple or almost black masses (sclerotia) are seen at intervals on the heads of rye, where they have usurped the position of the seed of their host. These sclerotia, or ergots, as they are popularly called, may be observed from June till late in the autumn, according to the nature of the species of ergot and host plant. In the autumn, they fall to the ground and remain in a resting stage throughout the winter. When the warm weather begins again, they show signs of awakening life by the appearance of small cracks, through which diminutive stalked bodies (stromata) make their way. In, the head of the stroma are numerous flask-shaped cavities (perithecia) each of which contains a number of narrow cells (asci) and each of these in its turn contains eight thread-like spores or reproductive bodies. The mature spores escape from the perithecia about the time of flowering of the host plant, rye or grass, as the case may be. When a spore falls into a floret of a suitable host plant, it develops a so-called mycelium, and a honey-like substance called "honeydew" is abundantly produced. The honeydew exudes in large glistening drops from the floret. This sweet substance, which is eagerly sought by midges, flies and other insects, is filled with very minute microscopic bodies (conidia), another reproductive form of the fungus. The conidia are capable of immediate germination and are carried by insects to other plants. Thus what is known as "ergot disease" spreads rapidly, throughout the flowering season of its host. The mycelial threads continue to develop, and in time form a dark compact mass two or three times the size of the seed of the host plant. This new ergot eventually falls to the ground and the life cycle is complete.

Distribution And Host Plants

Dr. Staeger, of Berne, Switzerland, has firmly established the fact that each species of ergot has its own circle of hosts within which it moves exclusively. He has shown by successful experiments carried on for a number of years past, that ergot of rye will infect barley and the following grasses:

Reed canary grass (Phalaris arundinacea L.); Sweet vernal grass (Anthoxanthum odoratum L.); Sweet or holy grass (Hierochloe odorata [L.] Wahlenb.); Meadow foxtail (Alopecurus pratensis L.);

Plate I.

Tall oat grass (Arrhenatherum elatius [L.J Beauv.); Orchard grass (Dactylis glomerata L.); Quaking grass (Briza media L.); Canadian blue grass (Poa compressa L.); Kentucky blue grass (Poa pratensis L.); Meadow fescue (Festuca elatior L.); Reed fescue (Festuca arundinacea Schreb.); Barren brome grass (Bromus sterilis L.). l

Photo - F. Fyles. Ergot on grasses.

Tall oat grass (Arrhenatherum elatius [L.J Beauv.); Orchard grass (Dactylis glomerata L.); Quaking grass (Briza media L.); Canadian blue grass (Poa compressa L.); Kentucky blue grass (Poa pratensis L.); Meadow fescue (Festuca elatior L.); Reed fescue (Festuca arundinacea Schreb.); Barren brome grass (Bromus sterilis L.). l

He has also shown that ergots grown on any of these grasses which have been infected by ergot of rye are in their turn capable of infecting rye and barley. This is a very important point for the agriculturist. For instance, if holy grass infected with ergot is left to mature, the ergots will drop to the ground and repeat their work in the spring. There will then be still fresh honeydew on the holy grass (which is early blooming) when the first heads of rye or barley come into bloom. The rye and barley may then be contaminated, and from them the honeydew will be borne to later-blooming fodder grasses, and so on through a continuous chain of harm.

Poisonous Properties

The most important of the many constituents lately isolated from ergot is the very highly potent alkaloid ergotoxine, which with other harmful principles causes a disease known as ergotism.

Animals Affected

Ergot is poisonous to all domestic animals. Ewart states that "a comparatively small number of fresh ergot grains suffice to injure or kill a horse, cow, or sheep." It is a well-known cause of abortion.

Human Poisoning

Human beings have been poisoned by ergot from very early days, chiefly, however, in those countries where rye bread is used. The ergot is ground up with the grain, and the flour is thus rendered unfit for food.

Symptoms

The symptoms of ergot poisoning have been well described by J. H. McNeil, as follows: "Ergot stimulates the nerve centres that cause the contraction of the small blood vessels supplying the different parts of the body, and cause one of the two forms of ergotism, viz., a nervous form and a gangrenous form.

"Nervous Ergotism: In this form the contraction of the blood vessels of the brain produces dullness and depression. The animal also suffers from gastro-intestinal catarrh, refuses food, and gradually passes into a condition of general wasting. The nervous form, however, may assume an entirely different aspect, and the animal dies suddenly in delirium or spasms, or gradually from paralysis.

1Ergot has been found on the following grasses in the West: Agropyron Smithii, Deschampsia caespitosa, Agropyron tenerum, Agropyron repens, Calamagrostis hyperborea elongala, Bromus inermis.

It is impossible to say, until further study has been made, whether this ergot is identical with the ergot of rye, or whether it may be one or more new species typical of the West.

"Gangrenous Ergotism: In this common form, the checking of the blood, resulting from the contraction of the small blood vessels, causes a loss of a part or of all the limb below the knee or hock, of the tail or the ears. The form of the disease may manifest itself by the formation of ulcers at the top of the hoof or between the toes, and a toe may be lost or the entire hoof shed. The affected part dries, a small furrow or line of separation appears, completely surrounding the limb, dividing the living from the dead mummified tissue."

We are indebted to the Veterinary Director-General at Ottawa for the following reports of recent ergot poisoning in Alberta presented by one of his inspectors, Dr. W. H. McKenzie: January 4, 1915. - I have inspected ninety head of cattle, twelve of which were suffering from ergotism. Necrosis of the inferior third of the tail, about one inch of the superior extremity of the ear, and both hind feet, was observed in one animal. In two others, both hind feet had sloughed off at the pastern joint, in another an indented ring circumscribing the hind leg about six inches above the fetlock joint, below which the tissue was gangrenous, in three one claw was absent. The other visibly affected animals exhibited swellings and lameness in one or both hind fetlocks. Animals had access to stacks of rye straw since about the first of November. Owner advises that first symptoms were observed on or about the first of December."

Five animals had already succumbed to the effects of the poison before the inspection of Dr. McKenzie. Receiving information of a similar case in the same neighbourhood, Dr. McKenzie inspected thirty-four cattle.

"Six animals were found to be showing the effects of this poison, being lame, having enlarged fetlock joints, and showing a pronounced tendency to resume the recumbent position. The grain bins and rye stack were examined and a considerable quantity of ergot found. The animals in question had been fed on rye straw for about four weeks, and a slight lameness was first observed ten days ago. I was informed that a neighbour who fed rye to pregnant sows had 28 abortions. All rye straw was burned, and owner instructed to thoroughly clean the rye grain before feeding same."

Remedy and Means of Control: In the case of ergot poisoning the best remedies are preventive. Care should be taken that no ergotised grain is sown. All grasses bearing ergot, wherever seen, should be cut and burnt. During the flowering season, there should be a vigilant search for heads showing the glistening honeydew. These infected heads should be gathered at once, taking care not to brush them against other grasses. Remember one drop of honeydew contains enough conidia to infect a whole acre of rye. Burn all ergotised hay, and clean thoroughly all barns and stalls where it has been stored. Should animals show symptoms of poisoning, their food should be changed at once, and the assistance of a veterinary surgeon should be procured.