BUNT OR SMUT IN WHEAT.

Daily Southern Cross, Volume XXVI, Issue 3887, 5 February 1870, Page 7

BUNT OR SMUT IN WHEAT.

J The serious loss in some districts from the ' prevalence of bunt or stinking rust (Uredo fcetida) in the wheat crop .demands our attention, and encourages ua to offer some remarks on the character of this disease, and the meaus which should be adopted to guard against it. Of all the fungoid parasites attacking wheat, this is perhaps the most to be dreaded ; not so much on account of the quantity of grain actually destroyed, as of the filthy smell which smutty wheat possesses, and which results from the dissemination of the spores \ these, by means of a glutinous membrane, attach themselves on bein* set free to the healthy grains, and thus affect the whole sample. According to Mr. Bauer, whoproduced the diseaseby inoculating the seed grain, the fungus was present a fortnight before the ear emerged from tho sheath, and about twenty days before sound ears springing from the same root were in bloom. Spores or seed vessels of the fungus are at first white, but afterwards change to a sooty black. The grain is more or less altered, both in shape and colour, becoming rounder and of a dirty green ; but the epidermis remains intact, and it 13 only upon breaking through that we find the flour replaced by a mass of stinking black powder. So long as the skin remains Unbroken, the presence of bunt is not injurious, save by the loss of grain ; but as soon as a fracture occurs, either in the process of harvesting, threshing, or grinding, a cloud of black dust escapes. This dust consists of myriads of spores or seeds, each capable of propagation, whilst the odour pervading the wheat is most offensive, and the price is seriously affected, sometimes to such" an extent that 'it ia quite unfit for human food. We recently saw a lot of otherwise excellent wheat so affect/ed by smut, that it was sold for cattle food at certainly 10s. a quarter less than its value if clean — the purchaser intending to first pass it through water in order to remove as much as possible, and then grind it for cattle. The process by which, a plant becomes impregnated—how the spores find their way into the system — is a question that has occupied much attention and been frequently discussed, but which is by no means decided at present. Many suppose they pass in by the roots ; others, through the stomata or breathing vessels, which line the surface of the stem and under-surface of leaves. The size of the spore presents a difficulty, as it would appear too large to enter either by roots or leaves. The Bev. Mr. Berkeley, one of our best authorities on the subject, has experimented by placing good wheat in water containing "bunt." In a short time mould was visible on the spores. The young wheat from this seed was affected, although there had been no communication between the wheat and the shoots thrown out by the spores, thus proving that the spores must have passed into the cells of the wheat. When we bear m mind the vast number of spores contained in a single diseased grain, and the quantity of grain that may be affected by each, we <are only surprised that the disease is not more common than it is, I especially remembering how careless many I farmers are ay to their seed. If it is granted that the bpoi es becoming attached to a sound gram may produce disease, of which there is little doubt, then one means of prevention will be the careful selection of seed free from fungus. But it is often difficult to detect j it may exist in such minute quantities that neither sight nor smell can bo brought to bear on it. Hence, if we can submit our seed to a pi ocess which v> ill effectually remove or destiov the fungus, v.e to a great extent ensure a lie ilthy produce. Huch a pi ocess is known as pickling, and lias been practised from the earliest tunes. Roman autliozs rlluilo to steeping wheat in capons' blood. Tneie aie se\eial diffeient pickles in u->e, which we may divide into two groups — those depending upon the presence of an alkali sufficiently powerful to dissolve the greasy matter which causes the spoies to adhere to the grain; and such as contain a strong caustic, to destroy the fungus, and all diseased grains, which, if allowed to grow would be likely to produce poor corn. Chamber-lye and salt, soda and lime, arsenic, sulphate and zinc, and sulphate of popper (blue vitriol) are the principal agents employed. Of these we prefer blue vitriol, as being easily applied, and perfectly efficacious when used as described. We have never known a crop of wheat seriously iii]ured by bunt after the seed was properly pickled. The usual plan is to place a sack of wheat on a stone floor in a round heap, and pour over this a solution of blue vitriol — from ;flb. to lib. dissolved in three gallons of water — stirring and turning the wheat until the admixture is supposed to be complete. This is evidently a clumsy and defective process. We cannot ensure the perfect wetting of every grain ; and, if the caustic destroys the germs "of disease, the enemy may escape us after all. Secondly, we have no means of separating light and defective grains which, though nob actually diseased, are unfit for seed. The plan we recommend consists in having a hogshead cut m half for the reception of the fluid ; into this a closely made wicker basket with upright sides ia placed, to receive the wheat, which should be gently poured in — a bushel or six pecks being wetted at once. The solution should consist of blue vitriol dissolved in water, six gallons of the latter to each pound of vitriol. The more slowly the wheat ia introduced the better, as the light and defective grains seek the surface more readily. Everything that floats must be skimmed off with a cullender. As soon as the skimming is accomplished, the basket must be raised out of the fluid, and allowed to drain until the liquid ceases to run, and only drips ; then the wheat is turned out on a floor, thrown up in a heap, and will be ready for drilling in twelve hours, or may be kept for weeks. As the solution is absorbed by the corn, more must be added, in the proportion of one pound of vitriol to five gallons of water. A sack of wheat can be dressed in about twelve minutes, and the cost is very trifling. The residue, after all our seed has been dressed, may be poured on gravel walks to kill weeds. On looking for the original cause of fungoid disease, we must extend our view beyond the spores which are the immediate and apparent cause. It is now evident from investigation that germs of disease are present m healthy plants, but not developed, because the conditions are not favourable to their existence ; they are ready, like vultures, to seize their prey, only the food must be already decaying. The sickness of the plant is their health ; they are Nature's scavengers, to eat up what is perishing. If the soil is not in a suitable condition for healthy plant growth, either because deficient in important food materials, or because it contains an undue proportion of stimulants, or cold and insufficiently ventilated, owing to the presence of stagnant water — if the season is uncongenial, clouds and rain being more prevalent than sun and wind — evaporation cannot relieve the system, the Oblood of the plant becomes charged with matters that should have been expelled, and we have favourable conditions for active fungoid life. Or if we omit to change our seed, the vigour of the plant becomes impaired. Under any or all of these conditions, fungoid disease, in some form or other — more likely as mildew than* as amut — will be present, and. will~entati* more or less loss upon the crop. It is difficult to account for the prevalence of sniiifr after such a^fine dry summer ; it was principally confined to strong land, and it is ( possible that there was a period of growth wheri_ "the plant suffered for want of moisture/ Causes, are,- however, very obscure — often quite beyond us ; we know the results, and must be content if we "possess the means of battling with and overcoming our difficulties. Selection^ of goocTseed, constant change of. seed, and direful pickling will generally j. checkj I if not entirely. prewnt,,{ilij^at£a^saf the stinJang feist. — Field, .

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