THE TREATMENT OF SMUTS OF OATS AND WHEAT.

Waikato Times, Volume XXXVIII, Issue 3100, 28 May 1892, Page 2 (Supplement)

THE TREATMENT OF SMUTS OF OATS AND WHEAT.

Tke following paper is by Mr W. T. Swingle, an assistant in the Department of .Agriculture of the United Stares, who for a number of years has devoted speei-il attention to smut diseases. It is it.sued as a bulletin, its object being to place before the farmers, in concise form, the results of recent experiments made in America and Europe in the treatment of amuts. Jlea-re VV. Souter and Co., of Cambridge, kindly obtained the paper and presented it to the Waikato Farmers' Club, and at the request of the Club >ve. publish it WHAT AKK SMUTS ? Smuts are minute paras l .! iu p'ants belonging to the. great group hir.gi. By their action they becune disease of higher plants. The two smuts whn-h cause the, greatest damage are the loose smut- of oats and the stinking smut of ivhe»t. It is hoped the following brief descriptions will enable anyone to recognise them. TUK LOOSE SMITT OP OATS. In the case of the loose smut of oats the grains and usually the husks are transformed into a black powdery mass, consisting of the spores of the fungus intermixed with a few shreds of tissue of the plant itself. The oat plants first show signs of tho disease at the time of heading out, when, instead of a normal bead, a smutted one is produced. The smut becomes fully mature at the time of blossoming of the oats, and is then easily scattered by the winds. By harvest time the smut has often bean entirely blown away, leaving only the naked stalk remaining. The fungus is known to botanists as UstUago avciirc. TIIK STINKING SMUT OF WHEAT. This smut, unlike that of oats, attacks only the grain. Iu consequence the heads have nearly their normal appearance. Upon close examination the grains are seen to be swollen, of a greenish colour at first, but fiually brown or gray. If one of these swollen smutted grains be crushed, it will be found to be filled with a dull, brownish powder, which has a very penetrating and disagreeable odour. The presence of this odour, which has given rise to the common name, is a very good test for the presence of the smut. The smut is due to either of two very nearly identical fungi, TUlctia foetem and Tillctia tritici. AMOUNT OF DAMAGE. The amount of damage caused by the loose smut of oats is very rarely fully appreciated. Whenever careful investigations have been made, the per cent, of heads attacked by smut has been found to be considerable The average loss is from 5 to 12 per cent, in different localities. The percentage of smutted heads also varies in a given locality in different years. Usually the smut is not noticed at all unless it is very abundant, for by harvest time most of the smut has fallen from the diseased beads, leaving only the bare and inconspicuous stalks The question will no doubt be asked, Will it pay to treat the oats for seed when ouly 5 or even 10 per cent, of the heads are smutted ? It may be said, in answer, that the per cent, of heads destroyed by smut does not represent the amount that will be recovered by treating the seed. In all the careful experiments made with the methods of seed treatment described below, there has been found to be an extra increase beyond and above the amount that would naturally be expected by replacing smutted heads with sound ones. This extra increase is found to range from one to ten times the amount of direct damage resulting from the loss of the smutted heads. Besides this gain there is that arising from tlie fact that the oats raised from treated seed will produce a crop free from smut, if there are no snratty oats in neighbouring , fields. Takinir all these facts into consideration it is highly probabl; that it will bo found profitable to treat seed oats if they come from a field showing more than 1 per cent, of smutted heads, and it will certainly pay to treat the seed if it camo from a. field showing , more than 3 per cent, of smutted heads. It is a fair estimate based on counts made in many parts to estimate the net gain to 'io obtained by treating seed oats itt 8 per cent, of tho crop obtained. Since the aggregate value of the oat crop of tho United States from ISSOtoISOO was £406,142,521, tho net gain from a universal system of seed treatment would have been £32,491,401, for those years. Every farmer who raises oats is strongly urged to treat the seed unless, upon careful counts made in different parts of tho field, there are found to he less than three heads out of every hundred •smutted. Above all, do not conclude that becauso you have not noticed any considerable amount of smut in your fields it will not pay to treat the seed, unless the field from which it was obtained is known to be free from smut. It should also be remembered that the gain is just as real even if oats are not apaying crop, or oven if merely grown for straw, for there is found to be an increase in the weight of straw grown from treated oats. The stinking smut of wheat is uufortunately too well known and too much feared by both farmers and millers to need hert any recital of the damage it causes. Sufficient to say that wheu once introduced it usually increases year by year, until often 40 to GO per cent, of the grain is destroyed. Besides this, the remaining portion is rendered unsaleable as well as unfit for seed. Farmers do not need to be urged to treat the seed to prevent tliis smut, as they are only too glad to learn of any certain method of preventing the ravages of this foe. As the smutted grain is easily recognised by the odour, and as it is absent altogether from many parts of the country, it will be wiser not to treat the wheat for seed unless the smut is known to bo present. OTHER SMUTS. Loose Smut op Wheat.—ln addition to the stinking smut, wheat is ulso subject to a loose smut much like thai of oats, and, like that, without odour. As yet, no method of combating it can bo recommended. The loose smut of wheat is caused by ustiiago tritici. Bakley Smuts.—Barley is subjeot to two loose smuts, both somewhat like oat smut. They may be prevented by soaking, the seed barley for four houw in cold water, letting it stand four hours iu a moist state ic sacks, and finally treatingin hot water :ib dirented for oats and wheat, but only for five minutes, and at a temperature of 126 to 128 degrees Fithr. HOW TO PREVENT OAT AND WHEAT SMUT. It has been found that the infection of tho plant takes place wheu the seed is germinating , and from spores adhering to the seed when planted. If these adhering spores can bo killed, a crop wholly free from smut can be obtained. (N.B. —There is some good evidence to show that fresh manure of herbivorous animals containing smut spores may, if applied at tho timn of planting , , infect tho young plarjts. It is hardly necessary to.mention this manner of infection since almost no American farmsre manure grain fields in this manner. There is no danger in using well-rotted manures). The Jensen, or Hot-wateh, Treatment kor Oat and Wheat Smuts.— This method, discovered by Mr J. L. Jensen, of Denmark, in 1887, consists in immersing' the seed which is supposed to be infected with imut for a few minutes in scalding water. The temperature muse bo such as to kill the smut spores, and the immersion must not be prolonged so that the heat would injure the gerrnmative power of the seed. If the water is at a temperature of degrees Fahr., the sporoa will be killed, and yet the immersion, if not continued beyond fifteen minutes, will not injure the seed. The temperature must be allowed to vary, but little from 132-kleg. ; in no case rising highar than J3sdeg. or falling below 130deg. To iusure these conditions when treating large quantities of seed, the following suggestions are offered :— Provide two large vessels—as two kettles over a fire, or boilers on a cooking stove—the first containing warm water (say, llOdeg. to 130deg.), and the second scalding water (132ideg.). The first is for the purpose of warm-

iiicr the seed preparatory to dipping it into the second. Cnlws thi-, pr: ra'.i'.imi is taken, it will be difficult to keep the water in the second vessel at ;i proper temperature. The seed which is to be treated must be placed, n half bushel or nmw, ,it a time, in a clnsrxl vessel that will allow Free i-ntiancß n.n.l r\\X. of water on both sides. l<\)r this purpose ;i bushel b.u4;i-t, made of heavy wiiv. could he u-ei\ ; which with spread wire netting—say 1meehes to the inch —or an iron frame could be made at a trifling cost, over which the wire netting couhi b«.slret«h''d. This would allow the water to puns- lr<:<.-!y. and yet pievont any passing ot thu send. A sack made ot loi-.sely-woven 11• :ir< rial (as L'unny sio.U) conlil perhaps be used instead uf the wire basket. A perforated an vessel is in -ome. respects prefe.ra.Me to any of the above. How dip the basket of seed in the first vessel; after a ir.ometit lift it, and when the water has for the most port escaped, plunge it into the water again, repeating the operation several times. The object of the lifting and plunging, to which should be added also a rotary motion, is to bring every grain in contact with the hot water. Less than a minute is required for the preparatory treatment ; after which plunge the basket of seed into the second vessel. If the thermometer indicates that the temperature of the water is falling, pour in hot water until ifc is elevated to 132ideg. If it should rise higher than 132-Jdeg., add small quantities of cold water. This will doubtless be the most simple method of keeping the proper temperature, aud i-equires only the addition of two small vessels—one for cold and one for boiling water. Steam conducted into the second vessel by a pipe provided with a stop-cock, answers even better, both for heating the water aud elevating the temperature from time to time. The basket of seed should, very shortly after its immersion, be lifted, aud then plunged and agitated in the manner described above; aud the operation should be repeated eight or ten times during the immersion, which should be continued fifteen minutes. In this way every portion of the seed will te subjected to the action of the scalding water. Immediately after its removal dash cold water over it or plunge it into a vessel of cold watel and then spread out to dry. Another portion can be treated similarly, and so on until all the seed has been disinfected. Before thoroughly dry the seed can be sown ; but it may be thoroughly dried and stored if desired. Tho important precautions to be taken are as follows :—(1) Maintain the. proper temperature of the water (132J deg. F.), in no case allowing it to rise higher than 135 deg. or to fall below 130 deg. This will not be difficult to do if a reliable thermometer is used and hot or cold water be dipped into the vessel as the falling or rising temperature demands. Immersion fifteen minutes will not then injure the seed. (2) See that the volume of scalding water is much greater—at least six or eight times —than that of the seed treated at any one time. (3) Never fill the basket or sack containing the seed entirely full, but always leave room for the grain to move about freely. (4) Leave the seed in the second vessel of water fifteen minutes. The Hot - water Treatment For Oats.—The foregoing method is applic ablo to both wheat and oats. With oats the following slight modifications are probably advantageous : —(1) Have the water in the second vessel 143 i deg. F., and immerse the seed five minutes, cooling with cold water afterwards. Where large amounts of seed are to bo treated this will prove the most speedy form cf treatment, but great care must he taken to eee that every grain is thoroughly wetted. (2) Have the water in the second vessel at 132 - F., immerse the seed ten minutes and do not cool with cold water, but spread out at once to dry. This last is no doubt the best form of the Jensen treatment for oats, since it requires a shorter time than the regular method and the warmth of the graiu aids it materially in drying. Moreover, experiments have shown that seed treated in this way yields the most grain and straw. Neither of these modifications are recommended for wheat without more data than we now possess. Potassum Sulphide Trkataient for Oats.—ln this treatment the sued is left twenty-four hours in a one-half per cent, solution of potassium sulphide. The published experiments seem to show that a weak solution of potassium sulphide is nearly as good as the hot water. The potassium sulphide is cheapest in the " fussed" condition, in which form it costs about one shilling a pound. One pound of the sulphide should be disolved in 2i gallons of water. Place the seed in a wooden vessel and pour on the solution till the seed is covered several inches deep. Stir the solution before pouring it on the grain and thoroughly mix the seed several times before taking it out of the solution. The oats should stand in the solution twenty-hour hours, after which they may be spread out to dry. The solution gradually looses its strength and hence cannot be used more than three or four times without being renewed. It will probably be best to sow the seed as soon as possible and before it becomes thoroughly dry. Soaking the seed 12 hours iu a solution of twice the strength will no doubt prove effectual. Copper Sulphate Tbeatment yon Wheat.—Tin's consists iu immersing the seed in a solution made by dissolving one pound of commercial copper sulphate in 24 gallons of water for twelve hours and then putting the seed for five or ten minutes into lime water made by slacking one pound of good lime in ten gallons ot water. These treatments have all been tried and have proved effective. Probably the hot water is the best for general use. In some parts of the country seed wheat is treated in strong solutions of copper sulphate and no lime is used. This practice is much inferior, since it injures the seed, while those given here prevent the smut completely and at the same time do not injure the seed if carefully followed, In all forms of seed treatment care should be taken to spread the grain out to dry at once and by frequent stirring, prevent its spoiling. The treated seed should be handled only with clean tools and should be put in sauks disinfected by boiling fifteen minutes. If these precautions are not taken the seed may be infected again after treatment, especially in the case of stiuking smut of wheat. If the seed is to be sown broadcast it will not have to be so dry as if it was to be drilled. The seed may be treated with hot water a considerable time before planting if dried carefully, but it is probably better to treat just before planting. In conclusion, this bulletin will fail of its object if it does not induce you to treat your oats and wheat this year. It should be remembered that the recommendations here given are not from theoretical-grounds alone, but are justified by the results of extended and laborious experiments many times repeated.