PICKLING FOR SMUT OR BUNT.

Otago Witness, Issue 3611, 29 May 1923, Page 12

PICKLING FOR SMUT OR BUNT.

Although smut and bunt are commonly referred to as if they were exactly the same disease, the difference is very pronounced. Few farmers greatly concern themselves about the nature of fungoid diseases. Their chief consideration is to be able to get rid of them. Fortunately, although smut and bunt are two separate diseases, they are closely related, and pickling with either formalin or copper sulphate (bluestone) is effective against both of them. Smut is easily recognised by every farmer. It attacks wheat, oats, barley, arid grasses. The smut is produced in the ovaries and destroys the various parts of the flower. Smut is introduced into the crop by the spores being sown with the seed, or by being blown about by the wind from some diseased crop, or from grasses and weeds. The spores produced form a blackish powder, and the looseness of the spores serves at once to distinguish the disease from bunt, in the ease of which the spores remain compacted inside the wheat grains. In the ground the spores germinate about the same time as the grain on which they rest. The disease originates in the roots of the host-plants, and passes up the stems into the leaves and panicles. Bunt, or stinking smut, attacks wheat and barley, but will not affect oats. The spores do not escape from the wheat ears in a powder, but are enclosed in the ovaries and glumes. At first they are somewhat greasy, As far as is known, smut and bunt spores have the same manner of reproduction. It has been calculated that in a single bunt bali there are about 4,000,000 spores, each of which is capable of causing one, wheat plant to be smutted. Because of the smallness of the spores careful methods in dealing with the disease are essential. Pickling is universally recognised as the best method of dealing with smut or bunt, and either formalin or copper sulphate are used. To successfully destroy bunt two things are essential. The bunt balls must be broken or else removed from the grain. At first sight the latter process appears to be practically impossible, but this is not so. Owing to the fact that bunt balls are light enough to float on water the best method of getting rid of them is to pour the grain slowly into the pickle tub and in such a way that the heavy grain will not prevent the bunt balls from becoming separated. They will then float on the surface and may be easily removed. Owing to the fact that air bubbles remain on the surfaces of the grains, and many spores of fungus of both smut and bunt can nestle under these and never become wet, South Australian experts recommend a method of rubbing these grains together so as to break the air bubbles. After shooting a heap of loose grain on the floor the requisite amount of solution should be poured on the heap, which should then be turned over from three to five times. Where no suitable floor is available the next best method of pickling with a copper sulphate solution is to put about one bushel of seed in a bag, tie it loosely, and immerse the bag in the solution for about five minutes or so. English methods bear out the opinion of South Australian experts. In carrying out tesls to determine the best strength for solutions, instead of dipping the seed, the solution was slowly sprinkled over the grain at the rate of one gallon to two bushels. The seed was kept constantly stirred during the process, so that every grain was moistened. After sprinkling the seed was heaped on the floor and covered with clean sacks that had been soaked in the solution. These heaps ■were allowed to stand for a maximum period of four hours, and then spread to irv in a thin layer on a clean floor. Pic-kling solution should never be made too strong, but it should be at least what is known as a 1 per cent, solution. This is strong enough if the seed to be pickled is not very badly affected. The 1 per cent, strength is represented by lib copper sulphate to 10 gallons of water. For badlyinfected grain a little stronger mixture may be used, but anything over l|lb copper sulphate to 10 gallons of water reduces the germinating powers of grain rather considerably. English tests with formalin solution show that a mixture of one pint to 60 gallons of water gave as good control as a stronger solution, but anything over one to sixty was unsatisfactory. Professor Arthur J. Perking advocates pickling a few days before sowing for the following reasons:—When you pickle grain all the spores or seeds of the fungus are in the dormant or resting state, and in this state they are able to resist the action of the bluestone better than when thev are in active life. Moreover, however thoroughly you may pickle, it is always possible that individual spores may escape coming in contact with the bluestone; this applies particularly to those spores which are able to resist action of the bluestone; but as soon as they germinate their lender germinating tubes come in contact with the bluestone which covers flic grain, and this will bring about, their destruction. If you sow the wheat immediately after pickling, the moist earth or rain which follows will tend to wash away the bluestone, and spores which have escaped may then germinate without danger. Delaying seeding, therefore, has the advantage of rendering the action of pickling more complete than if you were to sow immediately. Wheat can be pickled several months before seeding without injuring germination, providing it is thoroughly dry subsequently to pickling. Pickled wheat left over at seed time would be safe to sow 12 months later if keDt; protected from the weather and vermin, from the general point of view of germination. On the whole, however, owing to

contamination from surrounding objeots, an t *ihf» carelo.sanest whioh obtains Ift such mailers, personally I .■should prefer to pick it? a seeorul time." Never plane p!*kied grain bank ifi the Uigs from which it was t ikeri unless they ha e ’>eei, thoroughly sterilised in a strong solution Aifhongh {)i«kling will prevent, srnut, i» s »>jfe<;t is not lasting, and seed may «|in* k!\ l>e-«»!ue remte< led. r i horoughness in pn-kling is just as essential as in treatnia oilier diseases, and unless care is j oxe'rci ed pi kling is labour in vain. 1