STINKING-SMUT OF WHEAT.

New Zealand Journal of Agriculture, Volume XXX, Issue 5, 20 May 1925, Page 302

STINKING-SMUT OF WHEAT.

II. FIELD EXPERIMENTS ON CONTROL.

J. C. NEILL,

Assistant Mycologist, Biological Laboratory, Wellington

A preliminary article on stinking-smut of wheat appeared in the Journal for September, 1923. It contained a brief account of the available knowledge of the disease and the results of laboratory experiments with certain treatments in control. The present article records the results for 1924 -25 of comparative trials in the 'field of sixteen of the most successful seed-treatments used in this and other countries for the control of this disease. - \ • ■ . • GENERAL PLAN OF EXPERIMENTS. Four varieties of wheat were used in the experimentsPearl, College Hunter’s, Purple-straw Tuscan, and Solid-straw Tuscan. The last-named was harvested in January, 1924; the other three were one year older, being in fact the same parcels of wheat from which the samples used in the 1923 experiments, referred to above, were taken. All had been machine-threshed in the usual manner, and, for the purpose of these experiments, were inoculated in bulk with one part of smut-spores to 750 parts by weight of seed. The sample of smut consisted of Tilletia Tritici (Bjerk.) Wint. only, and had been collected by the writer at Winton in February, 1924. Samples of the four wheats were separately put through the various treatments in as identical a manner as possible —300 seeds from each sample being put to germinate* in the laboratory at approximately the same time as the remainder were being sown at the Ashburton Experimental Farm. The Pearl and the Hunter’s were sown in the autumn, the Purple-straw and Solid-straw Tuscan in the spring. The ground used, for the experiments had • not carried wheat for at least seven years. The seed was sown in rows 5| yards long, with 1 ft. between rows, each row taking 100 seeds spaced 2 in. apart. A piece of flexible wire rope, with permanent marks at each 2 in. and a spliced loop at one end, was used both to line out the drills and to locate the exact position for each seed —the latter being sown by hand. This method is quick and accurate, since, the seed being visible during the whole operation, mistakes are readily noticed. The exact position of each seed is also found at any subsequent time by slipping the loop over the permanent marker-peg and stretching the rope along the row. Thus ’ in the subsequent counting operations each row may be divided into any desired number of subdivisions to facilitate statistical examination of the results. In the experiments recorded here the 25, 50, and 75 marks were given extra prominence, thus dividing each sown row of 100 seeds into four equal parts. Each treatment was given four rows, a total of 400 seeds, and the results recorded separately on each of ' the sixteen divisions thus made and calculated as percentages on twenty-five seeds. The Probable Error of each of the mean results tabulated was computed on these lines, but, since statistical examination

using this factor does not materially alter the obvious comparative significance of the data there given, the writer has refrained from further complicating the already rather overloaded tables. The data, however, will be gladly supplied to any worker to whom they may be of interest. Between each four rows of . treated seed two rows of untreated seed from the same original sample were sown and counted in the same manner. The tables are presented in the order of sowing. DISCUSSION OF TREATMENTS. COPPER CARBONATE. Copper carbonate was brought into prominence as a control for stinking-smut by the publication in- the Agricultural Gazette of New South Wales, in 1918, of the results of three years’ experiments. by Darnell-Smith and Ross. The favourable nature of these results has been in the main confirmed by subsequent workers, and to-day the copper-carbonate treatment is generally recommended by plant pathologists in Australia and in the United States of America for the control of stinking-smut. Copper carbonate is a simple chemical compound, insoluble in water, and is mixed with the seed in the form of dust. Several firms are now making copper carbonates specially adapted for seed-treatment, and three of these were used in the present experiments, viz. : ' No. 1Corona Coppercarb, made by the Pittsburgh Plate Glass Company, Newark, New Jersey, U.S.A. This product contains about half the proportion of copper compared with the other two brands, and is used at a double strength —the makers claiming that this ensures better covering of the seed, and hence greater effectiveness as a fungicide. ■ This material arrived too late for the autumn sowings, and so was used only with the two Tuscan wheats. The wholesale price, f.o.b. New York, is quoted at about rod. per pound. No — Stauffer’s Copper Carbonate, made by Wheeler, Reynolds, and Stauffer, San Francisco ;. New Zealand agent, G. J. Miller, Ferry Buildings, Auckland; wholesale price quoted at about is. 5d. per pound. No. 3 —Copper-carbonate sample supplied by Bowden Bros, and Co.', Ltd., Sydney, N.S.W. ; wholesale price at Sydney, is. 3d. per pound; makers not known to writer. Method - of Treatment used in Experiments. — Smutted seed was shaken vigorously for two minutes in a closed container with coppercarbonate dust in amounts proportionate to 4 oz. to the bushel for No. 1 and No. 2A, and 2 oz. per bushel for No. 2 and No. 3. The treatment marked Copper carbonate No. 2a ” in the table is No. 2 (Stauffer’s), used at the rate of 4 oz. per bushel of seed. Summary of Experimental-Results.—(a.) Effect on the smut: With the low to medium infections shown by the Pearl, Hunter’s, and Purple-straw Tuscan, all three copper-carbonate treatments (with the exception of a single head in the Hunter’s) completely controlled the smut. With the high infection shown by the Solid-straw Tuscan, control was not complete, though only . about | per cent, of the heads were diseased, as against about 30 per cent, with the untreated seed. (&.) Effect on the wheat-plant : In field germination, vigour of seedling, and number of heads harvested ' no significant differences were shown between the copper-carbonate-treated and the untreated seed— difference there was being slightly in favour of the former.

Practical Considerations. — The copper-carbonate-dust treatment has several important advantages over the bluestone and formalin methods at present in use in New Zealand. It is simpler, safer, less laborious, and can be done at any convenient time prior to sowing, since the treated seed does not specially deteriorate on keeping. It controls stinkingsmut just as efficiently, and effects a considerable saving of seed, since only the minimum quantity need be sown in the safe knowledge that the seed is undamaged. The main disadvantages are that a special machine is necessary to ensure proper mixing of the dust and seed, that copper-carbonate. dust is very unpleasant in its effects when inhaled by the operator, and that compared with bluestone and formalin the cost of the material is -high. For the first of these disadvantages several special machines are now being made suitable for treating large quantities of seed, and for smaller quantities all that is really necessary is a box or barrel fitted with a tight lid and mounted so as to be capable of fairly rapid rotation. An old barrel churn within which has been fixed one or two baffle-plates is quite suitable. For the second objection a dust-mask or a wet sponge or cloth over mouth and nose will largely avoid the trouble. The cost for material should be about |d. per bushel of seed. The treatment could probably be most efficiently and economically done in conjunction with the various seed-cleaning plants—the farmer receiving his seed cleaned and treated ready for sowing. , ■ BLUESTONE (COPPER SULPHATE). Bluestone has been in use since the eighteenth century as a seedtreatment for stinking-smut, and is still perhaps the treatment in most general use in New Zealand. The experimental results here given merely confirm the experience of many investigators and of most farmersnamely, that the bluestone steep, while fairly efficient as a controllant of stinking-smut, causes a marked loss in germination and in vigour of the seedling. Method of Treatment used in Experiments. — Smutted seed was immersed for ten minutes in solutions made up of i lb. bluestone to io gallons water and i lb. to 5 gallons respectively, allowed to drain in a wet mass for twenty minutes, and then spread out to dry. In each case half the seed was dipped, after treatment and before drying, in limewash made up of 1 lb. quicklime to 10 gallons water. Summary of Experimental Results. — (a.) Effect on the smut : With the low smut infection showing in the autumn-sown Pearl and Hunter's, all the bluestone treatments gave complete control of the smut. With the Purple-straw Tuscan, showing a medium infection, the i-to-io-gallon treatment failed to give complete control, though the i-to-5 was still effective. . With the high infection in the Solid-straw Tuscan, none of the bluestone treatments were entirely effective, though, all reduced infection to small proportions.. Liming slightly reduced the effectiveness of both solutions in controlling the smut. (&.) Effect on the wheat - plant: All the bluestone treatments showed a depressing effect on the germination, vigour of seedling, and number of heads harvested. This effect was more . marked with the older seeds of the Pearl, Hunter’s, and Purple-straw Tuscan. The stronger solution did more damage than the weaker, and liming reduced the damage in both cases.

Practical Considerations. — The advantage and disadvantages of bluestone can be discussed most effectively in conjunction with formalin, and will be dealt with under the latter heading. Whether the subsequent lime-bath is worth while must be left to the individual judgment on the figures presented, but there is a strong case in its favour where the i-in-5 solution is used. FORMALIN. Formalin was first suggested as a smut-controllant in 1895. The excellent results given by it in laboratory trials and experimental work led to its rapid rise in favour among plant pathologists, who have of recent ■ years generally given it preference over the older bluestone. On the farms, however, the formalin treatment is, in general, looked on with some suspicion, a suspicion which the experimental results recorded below will not tend to . allay. However, a considerable portion of the cereals sown in New Zealand are regularly treated by this method. Commercial formalin consists of a solution of the gas formaldehyde in wafer,. the sample used in the present experiments containing 39-2 per cent, formaldehyde (analysis carried out by the Dominion Analyst, Wellington). Method of Treatment used in Experiments.— Smutted seed was immersed for ten minutes in solutions made up of 1 pint formalin to 40 gallons water (1-320) and 1 pint to 60 gallons (1-480) respectively, allowed to drain in a wet mass for twenty minutes, and then spread out to dry on blotting-paper on the laboratory benches. When outwardly dry it was- placed in paper packets for conveyance to Ashburton for sowing. The “ presoak method ” consisted in soaking the seed in water at room-temperature for six hours, then steeping for ten minutes in 1-320 formalin solution, and draining for twenty minutes, followed by a rapid rinse in water before spreading out to dry as described. Summary of Experimental Results.—fa.) Effect.on the smut: With the low infection in the Pearl and Hunter's, all the formalin treatments showed complete control of the smut. With the medium infection in the Purple-straw Tuscan, both . the straight 1-320 and 1-480 steeps were completely effective, though a single smutted plant appeared in the presoaked 1-320. With the high infection in the Solid-straw Tuscan, on the other hand, the presoaked 1-320 was the only formalin treatment completely controlling the smut, the ordinary steep at 1-320 showing o-i per cent, of smutted heads and the 1-480 showing 0-5 per cent., as against over 30 per cent, in the untreated controls. " (b.) Effect on the wheat-plant: The straight formalin steep at both the 1-320 and 1-480 strengths proved extremely detrimental to germination and vigour of seedling, and this applies to all four wheats, although the injury to the. older Pearl, Hunter’s, and . Purple-straw Tuscan seed was much greater than to the newer Solid-straw Tuscan. In view of the fact that some workers have used these treatments without causing material damage to the wheat-plant, it appears that possibly some factor or factors may have been introduced in the present experiments which greatly accentuated the damage normally occurring with the formalin steep. The point requires further investigation. The 1-480 steep proved less harmful to the plant than the 1-320. The presoak method, however, with the Pearl, Hunter’s, and Purple-straw

Tuscan produced a slight improvement in germination and vigour of seedling over the adjacent untreated controls ; with the Solid-straw Tuscan these results were only slightly inferior. Practical Considerations.— The formalin steep may be considered as an alternative seed - treatment to the older bluestone steep. Both control stinking-smut very well, so that other considerations must decide the choice of the user. The present experiments, for the reason already stated, should be accepted with caution as a guide in the case of formalin, except in so far as they indicate the tricky nature of treatment carried out with this substance and the possibility of getting, through some unforeseen circumstance, a disastrously low germination in the crop. The best results are given by the presoak - formalin method. This treatment, although it involves some extra trouble, should be perfectly feasible in farm practice— extra trouble being well repaid in the certainty of obtaining a good and healthy stand. Where the straight formalin steep is used it appears that a strength of solution 1-480 can be advantageously substituted for the 1-320 strength employed. Both bluestone and formalin are cheap and readily procurable, the cost of treatment being rather in the. time and labour employed than in the price of material. It seems likely that both will be supplanted in the near future by some of the' newer materials and methods. HOT WATER. The modified Jensen method was used in the single experiment tried with hot water. The method is indispensable as a controllant of loose smut, and has been claimed as equally efficient in the case of stinking-smut. It has not yet had any extended application for this purpose. Method of Treatment used in Experiments— The smutted seed was immersed in water at 63° F. for six hours, dipped for ten minutes in water at 125 0 F., and spread out on blotting-paper, to dry. Summary of Experimental Results. —(a.) Effect on the smut : With the low infection present in the Pearl, the treatment gave complete control, and with the higher infections, though not completely eliminating the smut, it reduced its incidence to small proportions, showing 0-9 per cent, of infected heads, as against over 30 per cent, in the untreated controls in the Solid-straw Tuscan. It will be noticed that it also controlled the small percentage of loose smut present in the Purple-straw Tuscan. (&.) Effect on the wheat - plant : The treatment had a very depressing effect on the germination and vigour of seedlings with the older Pearl, Hunter's, and Purple-straw Tuscan seeds. With the new seed of Solid-straw Tuscan this effect, though still present, was reduced to small proportions. Practical Considerations.—This method has not yet reached the stage of practical application in New Zealand, but there are features connected with it, and especially in regard to the simultaneous control of both smuts, that may yet bring it to the forefront in importance. clarke’s wheat protector. This is a proprietary fungicide manufactured in England. The New Zealand agents are Harris Bros., Christchurch. It is widely used

throughout the South Island for the control of cereal smuts. It costs about 2d. per bushel of seed treated.

Method-. of Treatment used in Experiments. This followed as closely as possible the directions printed on the packet. The smutted seed was thoroughly wetted with solution made up in . the proportion of one part Protector to fifteen parts water. . It was, kept moist for one hour, and then spread out to dry on blotting-paper in the laboratory, later being put into paper packets for transport to the sowing-ground at Ashburton. Summary of Experimental Results.—(a.) Effect on the smut: Complete control was obtained with the low and medium infection of the Pearl, Hunter’s, and Purple-straw Tuscan. With the high infection of the Solid-straw Tuscan, o-2 per cent, of smutted heads remained, as against about 30 per cent, in the controls. (&.) Effect on the wheat-plant : This differed widely as between the Pearl and Hunter’s sown in ’the autumn and the two Tuscans sown in the spring. With the former, Clarke’s Wheat Protector had a very depressing effect on germination and vigour of the seedling, while with the latter the treated seed improved slightly in both respects over the untreated controls. This profound difference in behaviour, is more likely to be due to some error in treatment of the Pearl and Hunter’s than to the different dates of sowing.- Further work is necessary to settle the point. Practical Considerations. — The simple and concise directions for use printed on each packet are a great factor in the popularity of this well-known treatment. USPULUN. - Uspulun is the trade name of a preparation of mercury chlorophenate manufactured by Friedr. Bayer and Co., Leverkusen, Germany. Reports state that it is widely used as a seed-disinfectant in Europe and South America. It is claimed for Uspulun that, while, giving perfect control of stinking-smut, it not only does not injure the seed but actually improves both germination, vigour of plant, and yield. The British agents are Millwards Merchandise, Ltd., Manchester, and the price about 13s. per pound, or about g|d. per bushel of seed treated. . ■ Method of Treatment used in Experiments.— This follows closely the directions of the' makers. The smutted seed was steeped for one hour in a o-25-per-cent. - solution of Uspulun, and then spread out on blotting-paper to dry. . Summary of Experimental Results.-\a.) Effect on the smut : ' Complete control of stinking-smut was given by the Uspulun treatment in all the experiments. (&.) Effect on the wheat-plant : The experiments fully bear out the claims of the makers that wheat-seed treated with Uspulun gives a higher percentage germination in the field and greater vigour in the seedling than untreated seed. With the older seed of Pearl, Hunter’s, and Purple-straw Tuscan there was also an increase in number of heads harvested, . but with the newer Solid-straw Tuscan . a very slight reduction.

Practical Considerations.— relative advantages and disadvantages of the three similar seed-disinfectants, Uspulun*, Germisan, and Semesan, will be considered together under the heading of ■ Semesan. GERMISAN. . . Germisan is the trade , name of . a preparation, of mercury-cresol-sodium cyanide manufactured by the Saccharin-Fabrik, Aktiengesellschaft, vorm. Fahlberg, List and Co., Magdeburg, Germany, the British agents being Ronsheim and Moore, ' London. • Like Uspulun, it is claimed to control stinking-smut and stimulate the wheat-plant. The price is about 8s. per pound, or about 5|d. per bushel of seed treated. Method of Treatment used in Experiments. — The smutted seed was steeped for half an hour in a -per-cent, solution of Germisan, and then spread out on blotting-paper to dry. Summary of Experimental Results.—(a.') Effect on the smut : Complete control of stinking-smut was. given by the Germisan treatment in all the experiments. (&.) Effect on 'the wheat-plant : ■ ■ With. the Pearl, Hunter's, and Purple-straw Tuscan the percentage germination was higher than that of the untreated controls ; with the Solid-straw Tuscan it was slightly lower. Im all, the vigour of the seedling was increased by the treatment, and the total heads harvested in all cases showed a substantial increase over adjacent controls. SEMESAN. Semesan is the trade name of an organic mercury compound manufactured by E. J. Du Pont de Nemours and Co., Wilmington, Delaware, U.S.A. The makers claim that, like Uspulun and Germisan, it will control stinking-smut and at the same time stimulate the wheatplant. It - can be used in solution as a steep, or as a dry powder mixed with the seed. The price is about 13s. 4d. per pound, or about yd. per bushel by the steep method and about rod. per bushel by the dry method. ■. . Method of Treatment used in Experiments. —(a.'} Steep method : Smutted seed was steeped for one hour in' a o-2-per-cent. solution of Semesan, and then spread out on blotting-paper to dry. (A) Dry-dust method : Smutted • seed was thoroughly shaken in a closed container with dry Semesan at the rate of 1 oz. per bushel of seed. ... Summary of Experimental Results:—Py) Effect on the smut: Complete control of stinking-smut was given by Semesan both by the steep and dry methods in all the experiments. • (&.) Effect on the wheat-plant : The differences in percentage germination and vigour of seedling between the seed treated by the steep method and the adjacent controls varied with the four wheat varieties, but on the whole were too small to be significant. In the total heads harvested the two Tuscans showed a substantial increase in. favour of the treatment, and the Hunter’s a very slight and the Pearl a greater decrease.

GRAPHICAL PRESENTATION OF THE FIELD GERMINATIONS RECORDED IN TABLES I-4, Key to Numbers. — (1) Copper carbonate. Corona Coppercarb, 40Z. per bushel. (2d) Copper carbonate, Stauffer's, 4 oz. per bushel. (2) Copper carbonate, Stauffer’s, 2 oz. per bushel. (3) Copper carbonate, Bowden Bros., 2 oz. per bushel. (4) Bluestone, 1 lb. in 10 gallons water. (5) Bluestone, 1 lb. in 10 gallons plus limewash. (6) Bluestone, 1 lb. in 5 gallons water. (7) Bluestone, 1 lb. in. 5 gallons plus limewash. (8) Uspulun, steeped 1 hour in 0'25 per cent, solution. (9) Germisan, steeped J hour in 0'25 per cent, solution. (10) Semesan, steeped 1 hour in 0’2 per cent, solution. (11) Hot water, presoaked 6 hours at 63° F.; dipped 10 minutes at 125 0 F. (12) Formalin, 1 pint: in 40 gallons water (1-320); dipped 10 minutes. (13) Formalin, 1 pint in 60 gallons water (1-480); dipped 10 minutes. (14) Formalin, presoaked 6 hours; dipped 10 minutes in 1-320 and rinsed. (15) Clarke’s Wheat Protector, wetted with 1-15 solution. (16) Semesan, dusted at 1 oz. per bushelUntreated (controls) indicated by cross-hatching.

The dry-dust method gave a substantial increase in percentage germination, vigour of seedling, and totals heads harvested in all the experiments. Practical Considerations. — The three related disinfectants, Uspulun, Germisan, and Semesan, open up a new field in seed-treatment. In the present experiments not only are they perfect controllants for stinking-smut, but they have shown a remarkable stimulation of the growth of the plant. How far under farm conditions this stimulation will be reflected in increased crop remains to be decided. If the number of heads harvested per hundred seeds sown can be accepted as a guide, then, for instance, the dry Semesan treatment, giving an average increase over the untreated seed of 8 per cent., or 3-g- bushels on a 40-bushel crop, would amply repay the outlay in material and labour without any reference to smut-control. The long-time steep recommended is a serious practical handicap to the wet treatments, but this objection is eliminated ..with Semesan by the simple and apparently more effective dry-dust method.

Mean of Controls in Table 3. —-Dates of sowing, August 5 and 7. Plants — total, 103-8; percentage smutted, 9-8. Headstotal, 688; percentage smutted, 7-2. Plants showing loose smut, : 1-7. The above data (Table 5) are founded on weekly sowings of 200 seeds ■of Purple-straw Tuscan wheat, .1923 harvest, inoculated in bulk with one part of spores (Tilletia Tritici) to 750 parts by weight of seed. The sowings were carried out by Mr. J. G. McKay at the Ashburton

Experimental Farm, and the temperature and rainfall records taken by Mr H. P. Clayton at the Meteorological Station distant about two miles over flat country from the place of sowing. ' In the absence of soil temperature and moisture determinations on the spot, the only safe conclusions to be drawn from the table are that the percentage of infection given by similar seed varies widely according to conditions at the time of sowing, and that sowings made during the three winter months of June, July, and August are more likely to be heavily infected than those sown earlier or later The table is also useful in throwing some light on the wide differences in infection recorded for the four varieties in Tables 1-4. It is apparent that these differences are not necessarily due to a difference in varietal susceptibility, but in part at least may be caused by environmental differences during germination.

* All the laboratory germinations here recorded were carried out by the Seed Analyst, Mr. N. R. Foy, and his assistants, Messrs. Cooch and Traill. .

control .. .. .. JU y? vi'3 •• zu / uu-j izi u 4y ujv zz 5-4 * The Probable Error of each control is computed in combination with the next succeeding control.

* Percentage calculated.after, deducting loose-smutted. plants from total.

* The samples of Uspulun and Germisan used in these experiments were kindly procured for the writer by Dr. E. J. Butler, Director of the Imperial Bureau of Mycology, Kew, London.

* In these two sowings the seeds were planted r in. apart, 400 seeds being sown instead of 200 as in the other sowings of the series.

Date. Percentage Germination. Plants. Heads. trercentage In Field. nJ nJ O a> 'd Difference <D Difference 4—> +-> compared . compared . ✓. First Count. -First Count. a . TT with 8 tn e with Treatment. cn nJ . <D d <v Treatment. 'd 0 0 d 0 U d £ oJ Adjacent Controls. XI Adjacent Controls. Hi cJ 0$ bn tn bn bn bn ‘ tn bn tn O d Pe. rt nd H CD rQ g + rt r£-j rt H O U) 3 rQ 3 g .S 5 <D 3 or 8 u 0 d PJ 0 0 Total bound May, 1924. 1-1 1924- d d 0 i—< Ph O Mean e Ph a aJ 0) O 0 H Smu 0 <D co Ph Tota s Ph cn 0 O <1> H Ph lotal e Heads. Sound Heads. cn 0) Ph Heads. Heads. Control 28 95'5 6i-6 * 3-2i In. x-6o 57-o 114 • 2 x-8 820 2 0-2 Copper carbonate No. 2A 26 28 96-0 79’2 2'QO 1-72 71-7 287 0 0 2,126 0 0 4 12-9 + 13-2 13-2 ■Control. .28 95-5 8i-o r-44 r-88 72-0 144 3 2-1 1,062 4 0-4 Copper carbonate No. 2 26 28 96-0 79-o ■1-84 x-8x 69-5 278 0 O 2,118 0 0 + 2-6 + 2-9 Control 29 95’5 8x-o 1-56 2-18 79'5 153 I 0-7 I 001 1,883 3 0-3 Copper carbonate No. 3 26 29 96-5 83-2 1-28 2-01 78-7 .315 0 0 0 0 — 3-7 — 3'5 Control * 29 95'5 83-5 i-57 2-17 74-o 148 2 1'4 955 5 o-5 Bluestone, 1 lb. in 10 gals. 27 29 9 I- 5 75-0 2-04 r-66 68-0 272 0 0 1,682 0 0 — xx-8 — xx-6 Control 29 95’5 85-5 1-44 2-27 78-0 156 3 2-0 954 8 o-8 Bluestone, 1 in 10, limed 313 3 2'0 954 8 0-8 Bluestone, 1 in 10, limed 27 27 29 29 94’5 94’5 82-5 82-5 1'32 1’32 i-86 i-86 78-2 [78-2 313 0 O 1 ,698 0 0 — 8-o — 7-4 Control 29 95'5 83-0 i-34 2-22 80-5 161 , I o-6 ■ 892 5 o-5 Bluestone, 1 lb. in 5 gals. 27 29 79'5 49'7 r-56 1-50 54-5 218 0 0 1,073 0 0 — 40-1 39-7 Control 29 95'5 87-0 x-o8 2-35 77-o 154 2 1-3 901 5 o-5 Bluestone, 1 in 5, limed 27 . 29 95-5 70-0 1-00 1-75 71-0 284 O 0 1,484 0 0 — 12-9 — 12-5 Control 29 95'5 85-0 1-32 2-26 80-5 161 I o-6 804 3 0-3 Uspulun .. . . 27 29 98-0 92-2 1-40 2-27 88-2 353 0 0 1,583 0 0 + 3'9 + 4-5 Control 29 95-5 85-0 1-45 2-28 76-0 152 0 0 719 0 0 Germisan . . 27 29 96-0 8.5-5 1-36 2-24 8x-7 327 0 0 1,532 0 0 + 2-2 -4-2-4 Control . . 29 95'5 82-5 x-8o 2-25 79-5 159 0 0 779 0 0 Semesan steep 27 29 97-0 78-2 1-28 2-07 78-5 314 0 0 1,482 0 0 — 4-5 — 4’4 Control 29 95-5 82-0 1-83 2-10 77-5 1.55 2 i-3 774 4 o-5 Hot water .. 26 ■ 29 94’5 43-2 2'44 1-83 46-7 187 0 0 1,081 0 0 — 28-7 — 28-3 Control 29 95’5 80-5 .1-83 2-07 7i-5 143 I o-7 744 3 o-4 Formalin, 1 pt. in 40 gals. 27 29 93-o 37'2 1-40 1-78 37-2 149 0 0 877 0 0 - 40-7 — 40-2 Control 29 95'5 81-5 1-84 2-09 71'5 143 3 2-1 735 8 I-I Formalin, 1 pt. in 60 gals. 27 29 96-0 42-5 2-04 r-88 42-2 169 0 O 968 0 0 — 34-i — 33-i Control 29 95-5 84-5 r-44 2-06 8o-o 160 6 3’7 735 • II i-5 Formalin, 1 in 40, presoak 27 29 97-5 8 1-5 I-io 2-i6 77.7 311 0 0 1,417 0 0 — 3'3 — i-9 Control29 95-5 78-5 i-97 2-07 78-5 157 ■ 4 2-5 73i 10 1-3 Clarke’s Wheat Protector 27 29 68-5 48-5 i-45 i-79 44'5 178 0 0 977 0 0 - 31-4 — 30-x Control 29 95-5 76-5 2-08 2-10 73-0 146 6 4-i 694 18 2-6 Semesan dust 26 29 97'5 84-5 I-l6 2-14 8i-o 324 0 0 1,392 638 0 0 + 4'5 + 8-7 Control .29 95'5 8o-o 2-II 76-5 153 12 7'8 32 5-o Table 2--Hunter’s. -Hunter’s. Control 30 95'2 73-o 2-04 2-18 67'5 135 ■ 7 5-2 701 21 3-o Copper carbonate No. A 26 30 92-5 69-7 i-76 2-13 69-0 276 I o-4 1,429 I o-i + o-5 4-3-i Control 30 95’2 67’5 2'08 •1’69 64’5 1.29 5 39 ■ 720 13 x-8 Copper carbonate No. 2 26 30 96-0 68-2 i-44 x-86 70-0 280 0 0 1,456 0 0 — 2-0 + I-I Control 30 95'2 70-5 x-8o i-95 68-5 137 8 5-8 766 30 3'9 Copper carbonate No. 3 26 30 92-0 63-2 1-92 1-90 64-0 259 0 0 1,363 0 0 . — 8-x 5-3 Control 30 95-2 62-5 2-03 i-86 63-5 127 4 3-i 718 13 x-8 Bluestone, 1 lb. in 10 gals. 27 30 8-3-5 5i-7 1-48 r-68 57-7 231 0 0 • 1,235 0 0. — 16-0 — 14-6 Control 30 95-2 66-5 2-08 1-85 65-5 131 3 2-3 753 9 1-2 Bluestone, 1 in 10, limed 27 30 87-0 59-2 1-52 i'7i 62-5 25c 0 0 1,326 0 O — 9-6 — 8-8 Control ■ 30 95-2 61-5 i-8i 1-78 62-0 124 2 r-6 714 6 o-8 Bluestone, 1 lb. in 5 gals. 27 30 5b-5 38-2 i-44 i-43 43-7 175 0 0 1204 0 0 — 13-5 — xx-7 Control 679 0 0 — 13'5 — 11 -7 Control 30 30 95’2 95’2 6o-o 6o-o 1-82 1-82 i-77 i-77 59’5 59'5 119 119 7 7 5’9 5'9 679 20 2-9 Bluestone, 1 in 5, limed 27 30 87-0 5°-7 r-68 r-79 55-o 220 0 0 ,289 0 0 — 10-7 — 7-4 ■ Control 30 95’2 72-0 1-64 2-22 70-0 I40 9 6-4 765 31 4-0 Uspulun 27 30 91'5 77-7 1-32 2-13 75-o 300 0 0 1,435 0 0 + 2’2 + io-i • Control 30 95'2 67'5 1-65 2-07 59-o 118 16 13-5 639 68 xo-6 Germisan .. 27 30 95-o 71-2 1-72 2-16 68-o 272 0 0 1,407 0 0 + 7-4 +■ 20-6 20-6 Control 30 95-a 64-0 1-65 2-01 162-5 125 25 20-0 671 72 10-7 Semesan steep 27 30 95-o 64-8 1-32 x-93 65-0 260 0 0 335 0 0 . — 0-2 + 12’4 12-4 Control 30 95-2 62-5 1-82 1-98 6x-o 122 20 16-4 667 74 II-I Hot water ... ' .. 26 30 85-0 23-2 1-32 i-79 31-0 124 2 i-6 798 8 1-0 — 44-o — 40-1 Control 30 95-2 66-5 2’00 2-07 67-0 134 II 8-2 760 36 4'7 Formalin, 1 pt. in 40 gals. 27 30 84-0 8-2 0-68 x-8x 7'5 30 0 0 323 0 0 — 79'4 — 78-2 Control30 95'2 70-5 1-84 2-03 66-5 133 9 6-7 814 48 5-9 Formalin, 1 pt. in 60 gals. 27 30 93-o 20’8 1-24 1-91 2.3-7 95 0 0 788 0 0 — 49-2 — 44-2 Control 30 95'2 62-0 x-8o 2-03 62-5 125 18 14-4 14'4 737 737 88 88 12-0 12’0 Formalin, 1 in 40, presoak 27 30 95-o 62-8 2-32 2-09 63-0 252 0 0 1,429 0 0 ' — i-6 -I-xo-5 Control 30 95-2 62-0 1-90 2’10 59-5 119 I7l T 4'3 716 69 9-6 Clarke’s Wheat Protector ■ 27 30 64-0 30-5 x-44 x-88 36-7 147 0. - 0 - 1,040 0 0 — 29-8 — 24-8 Control 767 0 0 — 29-8 —. 24-8 Control 30 30 95’2 95 -2 62-0 62-0 2-06 2-06 2-01 2-01 91'5 6x-5 123 123 6 6' 4'8 4-8 767 26 3-4 Semesan dust ■ 26 30 91-5 70-5 2-12 2-06 72-0 288 0, f 0 1,528 0 0 + 8-8 + 13’0 Control 61-5 2'12 2-06 72-0 288 0 0 1,528 0 0 + 8-8 + 13-0 Control 80 30 Q.5’2 Q5-2 6i-5 2-07 60-5 121 6 4-Q 636 22 8*4

g- 1 3 3 3 ? g B 1 2 2 2 2 3 S 3 B B B " B 2 2 2 2 S ? Mill i j hii nnols-s’sif ? ?itiO;O s o°? rWohf® L S’.L 1 OS-;Sp;S|l|l|g 1 l& W= Fl. a : ’ I' j » 5 I ! f 5 ? ? ? S i » 9 g = x x :: 3>U; : “J: Kl: , ; +: 1: >: >: :::::::: US. : Treatment. Table 3. —Purple-straw Tuscan. > 1 -j Treated. u p CD ' ■V L.. U U. U, UU. U ui M M VV 9. X, <, V, M - rj v . v . v . - t gj U , 9, U. U, W V. U , 9, M M V V 'nt M M M X> 9; M x, V <, 9, M M V M M o j? Sown. gs gggggggggggggggggggs gg gggggg ggg ~ ggg gggg gg gg gggg gg gX g ggggggggg g COW OOW cost OOO Oo + +4 OOO ooxt oon, co o co 6 oow ooG dovr OON Co 44 »U>»U.»0»U.»0»0»0»0»0»lA»d»(A»6»6»6B6>i In Laboratory. [Percentage Germination. ggg'sssss'gs'gs | cn 6 6 in 6 to 6 6 6 cn cn xr cA xt 6 6 6 <r ui 6 6 6 to tocnxicnocnocntocA 6 6 6 to cA cn 6 6 6 6 <Ji to 6 cA cA to 6 6o6 to cA co 6 to cA do o do 6 xi cA to cA Percentage. First Count. In Field. I ? « OO; g , 1+ ? WWWW WWW to co to co to co to co co to CO C- co co toco toco to co co co co co co CO !— i 2Bfgg;g§,gg^g'gS.Sggg'gggg t g. §SXg§ £Sg££gg<2£g^ggg^gXgXgg ? Mean Height. CO CO'O OO'O OOO XI OO Ch 00 CO C0<O <O VO CD KO «O CO CO CO GO COkO OOkO GOO CO COO O Ch Cn Cn -£» cn -U. to Cn h CiW A ChCn ChCn o'oi Cii+■ A g 4- Ci Ci Ci Ci XI O O XI o O W UJ OiOJ o\d O)H 4- H M IO Co to ChCn CD COH Ci O CO to O x} h >h COO g XJCi h co CO M COCO — 'CD H Co H Ch CO m IO WO h to Cn 00X10 Ch X} co XI O oOokoI+on+n+noOoConwo + woooookooJ.wkA § 6 6 6 + 6 6.+ w + + 6 + owiA<Juup< 6 6 6 to 6 + + + + 6 + + + Final Count (Mature Plants). M CO M CO M CO M 10 M 10 M CO M CO M CO M CO M CO M CO M CO M CO M CO M CO M CO M L> H Io H IO tO H H MM tOMtOMtOMtOMMMtOMM M 10 M tO M SJSJSWuFIi L L Cn XI XI XI -w O O O M CO Chw MCOCO M Ch XT CO XI to O XI aw to CO to to o O CO -k ChCn Ch co ChO CO Ch XI XI CO 4- to M too og w coco ax O H Total. Plants. i •fj § g Smutted. * 6 HOiw 6 <i oow 0*1 6 cA ooot 6o<5>xr4 w Ji M<r 6> to 6 J. 6 xi oSmm t-S uS to oS 6 6> 6 ck co dh 6 Percentage smutted. g 1 w Hen HMOg ChCO Ch XI m O W -g XI to Chg- Cn to O Cn ChCO O CO M M COCn co Ch-g to CO Ch M Cn O COO IO Cn CO to O to IO ODO Ch Ch M OO Qg CO Total. | Heads. i*1 1 :: .n Control ■ . . Uspulun . . Control Germisan Control Semesan steep Control Hot water Control Formalin, r pt. in 40 gals. Control Formalin, 1 pt. in 60 gals. Control Formalin, 1 in 40, presoak Control Clarke’s Wheat Protector Control Semesan dust .. Control •■;.. - ■ . - - ■ .' Control Copper carbonate No. 1 .. Control Copper carbonate No. 2 .. Control Copper carbonate No. 3 .. Control Bluestone, 1 lb. in 10 gals. Control Bluestone, 1 in 10, limed Control Bluestone, 1 lb. in 5 gals. Control Binestone, t in s. limed . . Treatment. ■ ■ .' ’• 4* 10 • • to 2oHNwwg>oo o o gowAw Smutted. ■ . N .'-K • -K • -K • • H • A • 44... • - •r <| Treated. KO » UU.U.U.O.U.U.U.U.UMSIVJMMM'M'JM ■QMMMMMMMMMMMMM » Sown. §« totocococoto-gcoco co-gcocototococo MM M M Co < O. N 6o OtWWHOCw H W H W\6 W OO 6 OlWKO li O W _N N «5ww W 6> H 4 6> CO H KO W H 4 oow 4 oo4 Percentage smutted. + + 1 1 1 1 + + 1 II 1 1 + 1 1 + + +I 1 I+ + +I 1 1 1 + 1 + • O Cn CO 0‘co’-g'co*co‘0i‘4n't0‘0>'co’4-‘0'0' co' <HtOHwww<»4w44w<r + « M+4w+6+t6 6H<tw6o 4 6ow' Total Heads. <h X . o M £/ >> O g. c §£x 3 + + + + + + + + +.+ + + + + + + + + + .1 1 1 + + + + 1 1 I+ + + •co*gK-4x-K>*M , 4x* ; to ; m ; * m ; ; ; m ; ’ m • to co CO CO O CO O O XI m co w M o O Ch to CO 00 to cn M Ch XI CO CO Ch XI Ch XI 1 Sound Heads. trols. 3 5 Plants showing Loose Smut. '§>'§>'§>£ £ Co In Laboratory. ' £5 §'£'§'2 SSS o 6 M K> CO Ln 4KKJ 'o OOCOU S M ►? 4? tScnOoObScncodooOMLntOLn p . Percentage. 3 g2 . ctq 1 6 6 6 n<Aw6 6 6 6J.n6G>wn6«6 • 5^S^ < S’g^S ) '8gaa^aS^'g 1 3 8'§%a5aaS 2 CP S S £ M • h g'dHH W4-L4k4k44k4k44. 4 JO co to CO to CO tOCOCOCOCOCOCOLO >_j i=> £ B' V" 1 w w w w w w 0 to co to co to co to co co to co 0- & SS 3.E2K §S , Sa§S5S£d'a£<2 HCOKO OKO h MCO to CO 6k Ul Ul 6k P «O OK h Ln M OK KO O OK KO 0 M to H Mean Height, r p. g"o SS£>£ § w OOH) agil. ?S h'ct.m'h § oooG-owwnwOoOowwOwwo 10 co -Ok m' k> cn "2 m KO "2mco M C) Final Count o’ (Mature Plants). p oOoNci.woNWNWNO'io'ioNwoo.woooooNOOwww 22 Ok M 8 ass 2 Total. § A M to KO o “-K 10 S 0 H 0 <3 N Ch N CO O W O W 0 0 Smutted. g g £o-koo>hmjo£o-wwwowoOoa 1 w O 6 OU. to 6 o’ co 6> 8 Percentage smutted. Total. K ?hi*hi&a?hhhhi a 1. 0 Smutted. . cSh4 N O. CT 4 M3 4 Percentage smutted. + + + I 1 1 + + + 1 1 1 1 + 1 + i i .i i + 2 ’ • Ln . to 0 ’ ok’ co ’ 4k ■ O’ O ’ 00 ’ £2- o> gt? • Jl w : <0 : 21 £ : <2 : w : w : £ •’ 0.6 C M3 O H xt w co 4 co do ' p£:g B gio < 4 22 CO XT + + + +'+ + 1 1. 1 + + + Kw 3S 2 £ + + + .1 1 1 + + + : : : : a21 2 Ln’ " M co 6 6. G. w Si ’?■'?’ t- -e 00 xt §g PS ■ to H4 W4 W4 HW H W O to H Plants showing Loose Smut. ' tO tO CO H 10 O H H O H O 10 CO H tO CO OK

Table I.-Pearl. Note.-200 seeds were sown for each control, 400 seeds for each treatment.

Date of Sowing. Plants. Heads. Plants showing Loose Smut. Ashburton Meteorological Records. . Total. Smutted Percentage smutted. . Total. Smutted Percent- . age smutted. Week ending Mean Temp. F. Total ■ Rainfall. 1924. 1924. May 17: 5U-7 Inches. 0-04 May 17 133 ' 2 1'5 I , 048 II 1-0 6 » 24 47'3 0-40 ,, 24 113 2 i-8 I , 056 8 0-7 3 » 3i ' 47’5 0-84 . 3i 107 16 15-0 803 98. 12-2 2 June 7 41-6 0-69 June 9 108 38 35’2 815 230 28-2 2 ,, 14 45’0 o-6l „ T 4 95 27 28-4 692 181 • 26-1 1 .> 21 39'9 0-24 ,, .21 47 5 io-6 507 67 13-2 0 „ 28 40'5 0-31 ,, 28 56 IO 17-8 . 538 105 19'5 ' 0 July 5 42-1 0-06 July 5 74 12 16-2 . 612 ’ 97 15’8 0 ,, 12 41-9 0-06 ' 12 90 9 io-o 685 56 8-2 2 ,, 19 43'9 0 ,, 19 101 15 14-8 683 82 12-0 I ' ,, 26 37'9 0-24 ,, 26 75 8 io-6 473 57 ■ 12-0 I Aug. 2 44’9 0-25 Aug. 2 103 4 3’9 640 18 2-8 I „ 9 41-0 o-37 „ 9 114 19 16-6 521 70 . 13-4 0 . ,, 16 5 46-I o-33 „ 16* 131 15 u-4 667 46 6-9 0 „ 23 ’ 42-9 0-09 ,, 23* 13° 19 14-6 57° 5i 8-9 I » 30 48-5 o-oi » 30 79 4 5’0 554 26 4-6 0 Sept. 6 46-7 0-21 Sept. 9 80 2 2'5 498 10 2-0 . 2 » 13 47-6 0 » 13 63 2 3-2 3i3 5 i-6 I - ,, 20. 54’3 0 ,, ■ 20 124 0 0 538 0 0 8 » 27 53'3 I -04

Table 5.- — Incidence of Stinking-smut in relation to Date of Sowing.