STINKING-SMUT OF WHEAT.

New Zealand Journal of Agriculture, Volume XXVII, Issue 3, 20 September 1923, Page 159

STINKING-SMUT OF WHEAT.

I. THE EFFECT ON GERMINATION OF SOME SEEDDISINFECTANTS.

J. C. NEILL,

Wellington.

The disease of wheat known as stinking-smut, sometimes called covered smut or bunt, is due to one or both of two closely allied fungous parasites, Tilletia Tritici (Bjerk.) Wint. and Tilletia levis Kuehn. From g the earliest historical times, and in all countries, it has caused greater aggregate loss to the grower than any other wheat-disease, and in New Zealand it is still the most formidable enemy of the wheat- crop. Where no preventive measures, are taken stinkingsmut may take anything from 5 per cent, to 40 per cent, of the crop ; and, further, even a small percentage of smutted heads lowers greatly the market value of the wheat, rendering it unfit for milling, while badly smutted lines are unsuited even for use as fowl-feed.

Fortunately, since the discovery of the hot-water, bluestone, and formalin treatments of the seed-wheat it has been possible, under such conditions as prevail in the New Zealand wheat - growing areas, to reduce the amount of stinking-smut normally present to very small proportions.

In New Zealand the main, and possibly the sole, cause of infection is by means of spores of the fungus which become attached to the seed during harvesting and threshing. When the seed’is sown the fungusspores germinate at about the same time as the wheat-seed, and, sending out germ-tubes, which penetrate the tender seedlings, become established in the tissues of the growing plant. As the wheat-plant grows, the fungus grows with it, showing no outward sign of its presence until flowering-time, when it establishes itself ..in the young wheat-grains. Here the fungus grows rapidly . at the expense of the food material stored in the grain, finally converting the whole contents of the seed-envelope into a black mass composed of millions of the fungus-spores. The name stinking-smut is derived from the peculiar rancid smell given off by these smut balls/’ which imparts a distinctive mustiness to flour milled from wheat in which they are present in any quantity. As the outside coat of the grain is still intact it is only by fairly close observation of the wheat-ear that the presence of the smut can be detected. When the crop is harvested and threshed the smut balls are . more or less broken, distributing over the clean wheat their millions of contained spores, which adhere so tenaciously that no mechanical cleaning process will remove them.

In countries where a summer fallow system is practised, notably in north-western America, infection of the soil by wind-borne spores liberated from the threshers becomes, in some years, a factor of great importance in the spread of smut. If the autumn wheat is sown in

such infected soil while dry, then, after the first rain, both wheat-seed and smut-spore germinate together— ideal condition for the parasite. Previous treatment of the seed would in this case be largely ineffective in preventing infection, the most hopeful method lying in the breeding of immune varieties of wheat. Fortunately, only very exceptionally are such conditions likely to occur in New Zealand.

Under present conditions, therefore, the problem of stinking-smut control in this country consists in finding some means whereby the smut-spores carried by the wheat-seed may be destroyed without injury to the wheat itself, and which will be cheap and easy to apply under farm conditions. A review of the published accounts of experiments to this end conducted in other countries shows that. the best results in the past have been obtained by various modifications of the hotwater, bluestone, and formalin dips. Hot-water treatments, though effective if properly applied, are not adapted to farm practice, and 1 so are not included in the present inquiry.

Practically all observers agree that both the formalin- and bluestonedip treatments, if property carried out, will completely prevent infection by seed-borne spores, but there is equal agreement that both injuriously affect the germination of the wheat. Injury to the seed-coat of the grain in threshing seems to be' the predisposing cause of this harmful action of the fungicide, as the germination of hand-threshed seed does not appear to be materially affected.

Microscopical examination of samples of two of the wheats, presumably machine-threshed, used in the experiments here recorded showed injuries as follows : Pearl —Uninjured, 65 per cent. ; seed-coat broken, over endosperm, 7 per cent., over embryo, 26 per cent. ; embryo broken off, 2 per cent. Tuscan —Uninjured, 80 per cent. ; seed-coat broken, over endosperm, 3 per cent., over embryo, 15 per cent. ; embryo broken off, 2 per cent.

Hand-threshed seed is not a commercial possibility in New Zealand, but every effort should be made in machine threshing to minimize injury, and samples of seed-wheat that show much broken seed-coat when viewed under a hand-lens should be rejected.

Various modifications of the standard bluestone- and formalin-dip treatments have been recommended, the most promising of which are being tested in these experiments. Unfortunately, it has not been possible to test in the laboratory the current farm practice of sprinkling and turning on a floor as compared with the complete dip, but it is hoped to do this later under practical farm conditions.

The question as to whether delay in sowing seed which has been treated will injuriously affect germination is one of great importance, especially in a wet winter such as experienced this year. Formalin in particular has a bad reputation in this respect, but an elaborate inquiry in the United States by Hurd shows that post-treatment injury only takes place at humidities below 70°, a degree of dryness rarely attained by New Zealand air in winter. Further, it is stated that damage by formalin can be entirely avoided by washing in water after treatments Part of the present series of experiments is designed to verify these statements, though a complete test can be made only under field conditions.

In recent years two other promising methods for the disinfection of seed have been discovered—a dry treatment with copper-carbonate dust, introduced by Darnell-Smith in New South Wales in 1917, and a wet process using certain organic mercury . compounds (uspulun, germisan, chlorophol, &c.), which has given good results in Germany, and which it is hoped to test here when supplies of the compounds become available. The copper-carbonate dry-dusting treatment of Darnell-Smith offers many practical advantages over any of the wet methods, and it is claimed for it that germination is rather increased and strengthened even after prolonged post-treatment storage. While showing good results in the recorded experiments on smut-control, there appears to be some doubt as to whether it is as effective as the formalin or bluestone. This can' only be settled for local conditions by careful field experiments in the wheat-growing areas of New. Zealand:

The present high cost of copper carbonate — 6s. per pound—is a distinct disadvantage, though it is expected that if the demand increases the cost of production will be considerably reduced. Used at the standard rate of 2 oz. per bushel of seed the cost of treatment will be qd. per bushel, as against 3d. per bushel by the present methods. Still, if by using copper carbonate the rate of sowing can be reduced from 11 to 11 bushels per acre —representing is. 6d. at 6s. per bushel at an increased cost of 6|d., then there is a net gain ofii|d: per acre in addition to the convenience and ease of handling.

Another dry treatment, using a mixture of anhydrous copper sulphate and limestone, has given fairly good results in the United States, and it has the advantage of being considerably cheaper in cost of material.

The usual, farm practice in New Zealand is to treat the seed-wheat with either bluestone or formalin, which, although giving fairly satisfactory results in the control of smut, is considered to reduce germination to such an extent that an additional 10 to 20 per cent, of seed must be sown to ensure the requisite stand.

Taking the total seed-wheat used in New Zealand at 400,000 bushels, the annual loss due to this excess sowing is from 40,000 to 80,000 bushels. At 6s. per bushel this represents a cost to the growers of from £12,000 to £24,000 per annum. The primary object of the present investigation is to find how this wastage may be reduced or perhaps eliminated.

I wish to acknowledge the assistance received from the Officer in Charge and the staff of the' Biological Laboratory, Wellington, wherein the preliminary work recorded here has been —especially to Mr. N. R. Foy, Seed-analyst, and his assistants, who carried out all the germination tests here recorded ; to the Mycologist, Mr. G. H. Cunningham, for laboratory facilities and constant advice. Mr. F. E. Ward, Instructor in Agriculture, Christchurch, also supplied much helpful information. :

PRELIMINARY LABORATORY EXPERIMENTS.

These experiments were planned to give reliable data on one factor only of the stinking-smut problem—that of the actual effect on wheatseed, germinated under ideal conditions, of the more promising standard

methods of disinfection. The corresponding effects under field conditions, and the relative efficiency in control of the smut, will be taken up in future work in the held.

Methods.

Samples of seed were obtained from the Instructor in Agriculture, Christchurch, and three were selected (to represent the three classes of wheat chiefly grown in New Zealand)namely,.Pearl, College Hunters, and Purple-straw Tuscan. From each of these, twenty-four lots of 100 seeds (fair average sample) were counted out, placed in corked testtubes, and treated in duplicate as follows : —

(i.) Dry-dusting with copper carbonate. Weights of dry,, finely powdered copper carbonate, equivalent. to weights of | oz., I oz., oz., and 3 oz. per bushel, were vigorously shaken with different samples of the seed.

(2.) Dry-dusting with a mixture of 50 per cent, finely powdered anhydrous copper sulphate and 50 per cent, finely powdered calcium carbonate. Weights of the mixture, equivalent to weights of 1 oz., 2 oz., 3 oz., and 4 oz., were shaken with the seed as in No. 1.

(3.) Bluestone dip : 1 lb. bluestone (copper sulphate) in 10 gallons water.

(4.) Bluestone dip : 1 lb. bluestone in 5 gallons water.

(5.) Formalin dip : 1 pint commercial formalin in 40 gallons water. Each of the dip treatments (Nos. 3, 4, and 5): were tested in . four different ways as follows’ :— .

A. Sample covered with the dip- solution" for. ten minutes, then surplus solution poured off and sample left in wet mass for twenty minutes, then spread out on blotting-paper in room to dry overnight.

Aw. Sample treated as in A, but rinsed in clean water immediately before being spread out to dry.

B. Presoak method: Sample first covered with clean water. for ten minutes, then surplus water poured off and seed left in wet mass for six hours, then treated as in A. -

Bw. Presoak method plus wash : Sample presoaked as in B, then treated as in Aw.

Three series of each wheat were thus treated. One lot was placed in the germinators on the day following treatment ; the other two lots were stored in corked test-tubes till tested, one at fourteen days and the last lot at twenty-eight days after treatment. With duplicates and untreated controls a total of 378 samples of 100 seeds each were tested for germination. The results are set out in the accompanying tables.

The following references apply to the bluestone and the formalin treatments in each of the three tables : — A treatment with solution 10 minutes, drain 20 minutes, then spread out to dry.

AwSame as A, but treated seed washed in water before drying. B—Soaked in water 10 minutes, drained 6 hours, then treated as in A. Bw— Same as B, but washed in water after treatment and before drying.

SUMMARY OF EXPERIMENTAL RESULTS.

(i.) Dry-dusting Treatments. Neither the copper-carbonate nor the anhydrous-copper-sulphate and calcium-carbonate mixture, caused any appreciable damage to the wheat-seed in vitality or germinatingpower.

(2.) Bluestone-dip Treatments. — The bluestone dip in all cases injured the germinating-power and vitality of the wheat-seed. This injury increased with the increased strength of the dip, and also with the length Of time that the seed was held in storage after treatment. Washing in water after dipping materially reduced this injury. The presoak methods increased the injury caused by bluestone. Deterioration on post-treatment storage was more pronounced with the varieties Pearl and Tuscan than with Hunters.

(3.) Formalin- Treatments. — The effect of the formalin dip varied considerably with the different wheat varieties. Pearl appeared to be uninjured by the dip even after twenty-eight days' post-treat-ment storage. This result is very surprising when considered in relation to the large amount of broken seed-coat in the sample, as specified earlier in this article. Hunters showed a certain retardation of germination the i day after treatment by all the formalin-dip methods. After post-treatment storage for fourteen days the vitality of the seed was distinctly impaired. This was reduced by washing the seed in water after dipping, and was entirely eliminated by the preliminary presoak method. The twenty-eight-days post - treatment storage results showed a decrease in vitality ■ all round—reduced to small proportions by presoaking. Tuscan gave results very', similar to Hunters, with slightly greater advantage by, presoaking.

GENERAL.

The experimental laboratory results here recorded, while in part agreeing with the published records of work in other countries, cannot be accepted as a reliable practical guide until confirmed and extended by field trials in New Zealand. The methods which show least damage to the seed may not be efficient in controlling the smut, and a method showing good laboratory results ! may be impracticable on the farm. Further, the relative cost of each method must be balanced against its efficiency. The most instructive feature of the tabulated results lies not in the ' total germination, but in the proportion of seed which had germinated at the third-day and sixth-day ,counts respectively. It is probable that in the field very few of the seedlings whose germination is included in the subsequent counts would ever develop to grainproducing plants.

1 Quick and strong germination of the seed is a vital factor not only in the subsequent vigour and productivity of the crop, but also in immunity from attack by stinking-smut and other parasitic fungi.

' ‘ ' LITERATURE CONSULTED. Braun, H. : Presoak Method of Seed Treatment. Journal of Agric. Research, vol. 19, pp. 363-391, 1921. Effect of Delayed Planting of Seed Wheat treated with Formalin. Phytopathology, vol. 12, pp. 173-179, 1922.

Darnell-Smith, G. P. : The Prevention of Bunt. Agric. Gaz. N.S.W., vol. 28, pp. 185-189, 1917. A Dry Method of Treating Seed Wheat for Bunt. Ibid,., vol. 32, pp. 796-798, 1921. ' ■ .

Heald, F. D., Zundel, G. L., and Boyle, L.W. : The Dusting of Wheat and Oats for Smut. Phyto., vol. 13, pp. 169-183, 1923. -

Hungerford, Chas. W. : The Relation of Soil-moisture and Soil-temperature to Bunt Infection in Wheat,. Ibid., vol. 12, pp. 337-351, 1922.

Hurd, Annie May : Injury to Seed Wheat resulting from Drying after Disinfection with Formaldehyde. Jour. Ague. Res., vol. 20, pp. 209-224, 1920. Seed-coat Injury and Viability of Seeds of Wheat and Barley as Factors of . Susceptibility of Moulds and Fungicides. Ibid., vol. 21, pp. 99—121, 1921.

Stephens, D. Eq and Woolman, H. M. : The Wheat-bunt Problem in Oregon. Oregon Agric. Exp. Sla. Bull. 188, 42 pp., 1922.

Tisdale, W. H., Taylor, J. W., and Griffiths, Marion A. : Experiments with ■ Hot Water, Formaldehyde, Copper Carbonate, and Chlorophol for the Control of Barley-smuts. Phyto., vol. 13, pp. 153-160, 1923. /

Treatment. Germination Percentage. Pearl. Hunters. Tuscan. Average of the Three Varieties. Counts at days cd days tn d nJ tn ►>> d nJ tn d nJ nj tn >> d .nj d . nj >> tn d nJ days tn d nJ £ ■ days tn nJ tn r U tn d •d co cn ■s 0 CO 5 U5, rt nJ a? *0 co tO </) cn *0 O nJ (/) d nJ CO « £ S 2 £ CTj nJ tn >0 1 tO co £ -e CO vo (/) r O O cn aJ ’d H H to Copper Carbona!#. i j- oz. per bushel . . f Z 95 96 95 97 95 97 95 97 82 78 91 90 91 90 . 91 91 89 89 96 95 96 95 96 95 Z 88 94 94 94 1 oz. per bushel • . . £ f Z 97 97 97 97 77 98 98 98 83 96 96 96 82 96 96 96 95 95 95 95 6 7 94 94 94 73 94 95 95 2 oz. per bushel . . Z 93 97 9fc 98 96 98 96 98 7 C 77 95 96 95 97 95 97 87 84 96 93 98 95 98 96 }8 4 96 96 96 3 oz. per bushel . . $ ( 94 92 95 94 96 94 96 94 88 77 90 95 90 95 9i 95 80 76 94 93 95 93 95 94 Z84 94 94 94 50-per-cent. Mixture oj Copper Sulphate (anhydrous) and Calcium ' Carbonate. 1 oz. per bushel . . 6 95 97 95 97 95 97 95 97 86 92 90 97 90 97 9i 97 87 84 96 93 96 95 96 96 j 9c 94 94 95 2 oz. per bushel . . ( Z 95 95 96 95 96 95 96 95 94 89 95 92 95 92 95 92 88 85 95 95 95 96 96 96 ■ 91 94 94 95 3 oz. per bushel . . z 99 100 99 IOC 99 100 99 100 89 89 92 9i 93 92 93 92 89 83 96 94 96 94 96 94 91 95 95 95 4 oz. per bushel . . z 95 9i 95 93 95 93 95 93 94 88 99 97 99 97 99 97 9i 90 96 4 oz. per bushel 95 96 96 91 96 96 Bluestone (1 lb. in 10 gallons water). 36 - { 30 A . . ( z 42 37 77 76 90 96 90 96 4 c 27 93 79 94 82 95 86 69 68 84 89 86 9i Z J 35 78 89 9i Aw. . . . . . f z 72 97 97 97 54 77 84 84 z 53 82 92 92 61 95 96 97 39 88 ■ 92 92 B 4i 79 9i 92 43 76 83 87 47 79 9i 94 88 z 35 8c 88 89 37 78 86 87 33 80 87 89 J 39 79 Bw. . .. . . £ c Z 52 56 82 83 85 89 88 9i 52 47 co co 9c 88 93 9i 5i 82 88 91 Bluestone (lib. in 5 gallons water) A . . { z 39 39 7i 65 92 88 96 92 12 20 74 77 88 85 9i 88 39 44 64 67 8c 90 83 92 z J 32 69 87 90 Aw. . ... . . | z 44 37 88 76 96 92 97 92 . *4 22 72 79 86 90 87 90 50 3i 84 80 93 92 93 93 z 33 79 9i 92 B { z 21 61 79 84 25 63 82 85 33 75 9i 93 62 84 84 16 52 73 77 25 56 72 79 38 67 85 86 Bw. . ■ . . ■ ' ! • • | Formalin z 5° 54 78 86 92 9i 93 95 54 40 75 70 86 82 ■ 90 87 £ 84 87 9i 94 9i 94 z J 49 86 89 91 (1 pint in 40 gallons water) A . . . . . . { z 97 99 99 99 61 94 94 94 66 94 94 95 z 76 93 95 95 95 67 9c 9i 9i 70 94 94 94 ) 95 Aw. . .. .. f z 90 92 92 92 84 93 93 93 83 99 99 99 z 86 06 ' q6 98 98 98 98 84 94 94 94 88 99 99 99 B ’ P .• L- ( 88 90 9i 9i 88 97 97 97 '85 93 93 93 86 z95 95 95 95 75 83 85 85 90 98 98 98 93 c Bw. . .. .. z 93 94 94 94 70 90 90 90 92 95 95 95 87 Untreated. 98 98 96 98 98 72 9 1 91 92 96 97 98 97 97 J 94 95 96 96 81 98 .98 Controls . . . . ] 95 96 97 95 93 97 94 92 95 97 95 95 99 100 95 9i 42 37 72 61 4i 35 52 56 39 39 44 37 21 16 50 54 97 93 90 98 88 95 93 98 95 95 95 96 97 96 97 97 98 55 49 94 94 94 94 95 94 89 94 96 98 96 98 96 98 88 97 97 97 94 95 97 97 95 96 98 95 94 95 97 96 95 99 IOC 95 93 77 76 97 95 79 8c 82 83 7i 65 88 76 61 52 78 86 99 95 92 98 90 95 94 98 96 96 97 100 95 97 97 95 96 98 96 94 95 97 96 95 99 100 95 93 90 96 97 96 91 88 85 89 92 88 96 92 79 73 92 91 99 95 92 98 9i 95 94 98 96 96 97 100 95 97 97 95 96 98 96 94 95 97 96 95 99 100 95 93 90 96 97 97 92 89 88 91 96 92 97 92 84 77 93 95 99 95 92 98 9i 95 94 98 96 97 98 TOO 82 78 77 6 7 70 77 88 77 86 92 94 89 89 89 94 88 4 C 2/ 43 37 12 20 14 22 25 25 54 4° 61 67 84 84 88 75 7° 72 55 49 91 90 98 94 95 96 9c 95 90 97 95 92 92 91 99 97 93 79 76 78 74 77 72 79 63 56 75 70 94 9C 93 94 97 83 90 91 94 94 91 90 98 94 95 97 90 95 90 97 95 92 93 92 99 97 94 82 83 86 88 85 86 90 82 72 86 82 94 91 93 94 97 85 90 91 94 94 91 91 98 94 95 97 9i 95 91 97 95 92 93 92 99 97 95 86 87 87 9i 88 87 90 85 79 90 87 94 91 93 94 97 85 90 92 95 94 89 89 83 73 87 84 80 76 87 84 88 85 89 83 91 90 36 30 54 39 47 33 52 47 39 44 50 31 33 38 51 49 66 7° 83 88 85 90 92 96 81 89 94 98 96 95 96 94 96 93 94 93 96 93 95 95 96 94 96 95 69 68 77 88 79 80 82 82 64 67 84 80 75 67 84 87 94 94 99 99 93 98 95 97 98 96 98 99 96 95 96 95 98 95 95 93 96 95 95 96 96 94 98 96 84 89 84 92 91 87 90 88 8c 90 93 92 91 85 9i 94 94 94 99 99 93 98 95 97 98 96 98 99 96 95 96 95 98 96 95 94 96 96 96 96 96 94 98 96 86 91 84 92 94 89 93 91 83 92 93 93 93 86 9i 94 95 94 99 99 93 98 95 97 98 96 98 99 j 88 ) 82 }8 4 p4 j 90 b 1 b 1 b 1 b 5 b ] 39 ] 32 ] 33 b ] 49 ] 76 j 86 J 86 |87 j-88 94 96 96 94 94 94 95 96 78 82 79 82 69 79 62 86 94 96 92 94 97 94 96 96 94 94 94 95 96 89 92 88 88 87 9i 84 8c 94 9t 93 94 97 94 96 96 94 95 95 95 96 91 92 89 91 9° 92 84 9i 95 96 93 94 97

Table I. Seed, placed in Germinators One Day after Treatment.

Treatment. Germination Percentage. Pearl. Hunters. 1 Tuscan. Average of the Three Varieties. (/) rn rA r/) m (/) £ £ 03 Counts at (/) rf nJ c/> . rt *d r d nJ - nJ "d G5 r d 'd *d *d *d 0 rt nJ cn *•— CO co tn co to C/3 rt nJ 0 £ cd nJ (/) GJ nJ UJ <0 C/3 ctf nJ 0 CO nJ >■» a? nJ 0 .*5 kO — — — — — — — Copper Carbonate. | oz. per bushel . . Z 95 96 95 96 95 96 80 92 93 97 93 97 93 97 94 95 96 96 96 96 96 97 1 ) 92 95 95 96 i oz. per bushel Z 94 89 95 94 95 94 83 84 9i 95 92 95 92 95 93 97 96 97 96 97 96 98 Z 5 90 94 95 95 2 oz. per bushel . . z 93 95 94 96 94 96 80 93 93 97 95 97 96 97 93 9i 94 95 94 95 94 95 Z J 91 95 95 95 3 oz. per bushel ' ‘ { z 94 92 94 96 94 96 83 81 94 98 94 98 95 98 86 92 92 94 93 95 93 95 z .) 91 94 94 95 go-per-cent. Mixture of ■ Copper Sulphate ( anhydrous) • and Calcium Carbonate. 1 oz. per bushel . . f z 94 98 96 98 96 98 89 86 92 89 92 89 92 90 97 87 97 90 97 90 97 90 z 92 94 94 94 2 oz. per bushel . . z 97 92 98 96 98 96 86 80 83 3 oz. per bushel . . . . 80 90 97 90 97 90 97 94 97 96 100 96 100 96 100 z 5 91 96 96 96 3 oz. per bushel z 94 97 96 98 97 98 95 92 95 92 95 92 90 96 93 96 93 96 94 96 z ) 90 94 94 95 4 oz. per bushel . . £ z 97 97 97 97 97 97 89 84 94 93 94 93 94 93 95 95 95 96 95 96 97 96 ( 5 93 95 95 95 Bluestone (1 lb. in 10 gallons water). A < ( 56 81 A .. .. • . ;l 94 61 82 9i 94 65 76 83 85 z 78 88 9i z 35 73 89 62 82 88 92 61 76 85 90 > ■J / z° Aw. . ... ‘ { z 54 9i 96 58 78 86 90 z 62 84 84 93 78 96 97 59 73 83 90 J B . . z 54 4i 80 74 90 89 63 52 77 86 86 90 90 92 61 57 76 7° 86 80 O'' TT co CO z 3 51 77 85 89 Bw. . . I i .. £ z 63 89 94 69 85 88 90 z 70 88 92 93 65 88 93 85 93 96 97 Bluestone (1 lb., in 5 gallons water). a . . .. f 32 54 81 35 64 80 84 40 54 7° 77 z z 30 50 88 38 66 81 84 38 49 66 80 j 03 Aw’ . . . 1 . . f ( z 39 49 82 80 92 95 47 52 72 75 87 84 92 88 41 42 57 59 79 77 86 88 z ) 45 7i 82 90 B .. . z 18 9 52 26 78 61 46 44 73 72 85 78 89 85 25 49 44 64 7i 74 76 81 I .) 32 55 77 78 Bw. . ... ’ ’ ’ { 27 71 88 46 74 82 84 63 69 81 85 z 42 7i 81 86 z 23 70 90 39 75 81 85 55 67 81 84 > Formalin (1 pint in 40 gallons water). A ' 80 A .. ... ,. z 1 93 96 96 33 95 95 95 67 84 85 z 65 88 z 96 96 96 30 83 90 90 7° 81 87 90 ) Aw. . ... ’ ' { z 95 98 95 98 95 98 82 B A j 79 9i 90 92 92 92 92 85 86 8? 90 87 93 87 93 z ) 87 9i 9i 93 B . . z 89 90 96 94 96 95 9i 95 93 96 93 96 93 96 89 94 92 95 98 96 98 97 z 5 91 94 95 96 Bw. . . . . . | z 93 94 95 97 99 99 99 96 97 97 97 z 94 96 96 .96 95 97 97 9i 95 95 95 92 93 95 95 ) , Untreated. ( 96 99 99 94 95 95 95 95 96 96 96 1 Controls . . . . | 95 96 94 89 93 95 94 92 94 98 97 92 94 "97 97 97 56 35 54 78 54 4i 63 65 32 30 39 49 18 9 27 23 93 96 95 98 89 ■ 90 93 95 96 J 94 94 96 96 86 92 92 92 90 92 92 92 1 r 93 95 95 95 96 95 96 95 94 94 96 94 96 96 98 98 96 96 98 97 97 81 73 9i 96 80 74 89 88 54 50 82 80 52 26 7i 70 96 96 95 98 96 94 94 97 99 96 97 95 96 95 94 94 96 94 96 ' 96 98 98 96 97 98 97 97 94 89 96 97 90 89 94 93 81 88 ■ 92 95 78 61 88 90 96 96 95 98 96 95 95 97 99 96 97 80 92 83 84 80 93 83 81 89 86 86 o° 83 ■ 80 89 84 61 62 63 52 35 38 47 52 46 44 46 39 33 30 82 79 9i 95 97 9i 94 86 93 97 91 95 93 97 94 98 92 89 90 97 95 92 94 93 82 82 77 86 64 66 72 75 73 72 74 75 95 83 91 90 93 . 96 99 95 95 92 93 97 92 95 95 97 94 98 92 89 90 97 95 92 94 93 91 88 I 86 90 80 81 87 84 • 85 78 82 81 95 90 92 92 93 96 99 95 95 92 93 97 92 95 96 97 95 98 92 90 90 97 95 92 94 93 94 92 90 92 84 84 92 88 89 85 84 85 95 90 92 92 93 96 99 95 95 92 94 95 93 97 93 91 86 92 97 87 94 97 90 96 95 95 65 61 58 59 61 57 69 85 40 38 41 42 25 49 63 55 67 70 85 86 89 94 96 92 95 90 96 96 96 96 97 94 95 92 94 97 90 96 100 93 96 95 96 76 76 78 73 76 70 85 93 54 49 57 59 44 64 69 67 80 81 87 90 92 95 97 93 96 *92 98 96 96 96 97 94 95 93 95 97 90 96 100 93 96 95 96 83 85 86 83 86 80 88 96 70 66 79 77 71 74 81 81 84 87 87 93 98 96 97 95 96 92 99 96 97 96 98 ’ 94 95 93 95 97 90 96 100 94 96 97 96 85 90 90 90 89 84 90 97 77 80 86 88 76 81 85 84 85 90 87 93 98 97 97 95 96 92 99 1 92 ] 90 b 1 b 1 192 b 1 ] 90 j 93 }57 j 62 } 7° j 35 ) 45 J 32 ) 42 } 65 J 87 b 1 } 94 j- 93 . 95 94 95 94 94 96 94 95 78 84 77 88 56 7i 55 7i 88 9i 94 96 95 95 95 94 94 96 94 95 88 84 85 92 69 82 77 81 89 9i 95 96 95 95 96 95 95 95 94 96 95 95 91 93 89 93 82 9° 78 86 92 93 ■96 96 95

Table II. Seed placed in Germinators Fourteen Days after Treatment.

Treatment. Germination Percentage. Pearl. Hunters. Tuscan. x Average of the Three Varieties. cn {/) £ £ (fl £ >> V) w 1 U), >> (/) (/) [X Counts at r2 o3 . nd ■b rt T3 rg rt aS nd rt 'S : 0 •b £ co 1 2 v© co CTJ 0 c3 T5 0 *0 CO v© * co v© J 0 S' ■ Copper Carbonate. J oz. per bushel per bushel . . f 96 I 97 96 96 97 99 96 97 99 99 97 97 99 99 97 91 99 89 9i 99 89 95 99 99 95 95 99 99 95 95 99 77 95 77 77 97 77 94 97 97 94 95 97 97 95 95 97 Z 88 96 97 97 95 88 96 97 97 i oz. per bushel 95 per bushel . . . 95 93 98 94 98 94 98 94 89 79 92 94 92 94 92 94 62 80 98 95 98 95 98 96 'Z }83 3 95 83 95 95 95 95 95 2 oz. per bushel per bushel . . I 9i 86 99 92 99 93 99 93 84 89 98 94 98 94 98 94 70 68 97 92 97 93 98 94 81 95 96 96 3 oz. per bushel per bushel . . I 90 92 94 95 94 95 94 95 88 85 94 94 95 94 95 94 64 66 95 95 95 97 95 . 97 z 81 94 95 95 3 81 94 95 95 Anhydrous Copper Sulphate and Calcium Carbonate. i oz. per bushel per bushel ' ’ f 95 I 93 95 95 93 96 95 95 96 96 95 95 96 96 95 92 96 87 92 98 87 94 98 99 94 94 99 99 94 94 99 79 94 90 79 99 90 96 99 100 96 97 100 100 97 97 100 z 93 96 97 97 97 93 96 97 97 2 oz. per bushel per bushel . . ( 94 I 94 94 95 94 97 95 95 97 97 95 95 97 97 95 9i 97 88 9i 97 88 90 97 97 90 90 97 97 90 9i 97 80 9i 79 80 96 79 94 96 96 94 94 96 96 94 94 96 z 94 3 88 95 95 J .95 88 95 95 95 3 oz. per bushel per bushel . '. I 94 96 98 98 98 98 98 98 90 . 90 97 95 98 95 98 95 81 81 96 95 96 95 96 95 z 3 89 96 96 96 4 oz. per bushel per bushel . . £ 95 95 96 99 97 99 97 99 97 9i 90 94 93 94 94 94 94 80 7 1 96 95 96 96 96 96 z 3 87 96 96 96 Bluestone (lib. in io gallons water) in 10 gallons water). A ., . 21 30 62 70 85 89 86 93 33 50 83 77 87 82 88 84 11 IO 66 76 85 9i 9i 95 ) 3 29 72 86 89 Aw. . 42 89 92 93 13 76 88 89 z 82 9i 30 89 82 92 93 93 94 .... 13 20 76 81 88 9i 89 93 26 82 9i 92 B . . c Z 8 14 43 52 7 1 80 76 9i 4° • 43 80 76 84 83 85 84 10 9 7 1 60 86 83 88 <oo co 85 J z 20 63 81 83 3 20 63 81 83 Bw. . L 21 25 82 65 94 87 94 87 14 12 63 64 76 79 77 80 18 68 84 84 Bluestone 21 25 82 65 94 87 ■94 87 • 14 12 63 64 76 79 77 80 Z 18 68 84 84 1 (i lb in g gallons water) in 5 gallons water). A . . f ’’Z 25 32 50 52 83 78 86 84 31 27 59 60 72 73 78 77 8 IO 49 44 73 66 78 75 z 22 3 52 22 74 52 79 74 79 25 81 92 92 34 75 87 88 25 77 9i 95 z 28 88 88 "Z 30 30 80 80 96 96 96 96 45 45 67 67 83 83 84 84 12 12 54 54 73 73 76 76 72 ) 07 72 07 C B 7 7 28 28 64 64 69 69 18 18 55 55 65 65 68 68 7 7 55 55 72 72 80 80 z 12 z 47 74 I 11 II 4i 41 7i 7i 80 80 21 21 5i 5i 61 61 68 68 12 12 56 56 75 75 81 81 3 47 . 74 Bw. . I 15 11 53 59 74 83 78 86 36 32 61 64 77 72 78 73 21 19 66 60 81 81 86 83 z 3 33 60 78 81 Formalin (i pint in 40 gallons water). ( A 93 93 97 97 97 97 97 97 21 21 85 85 88 88 89 89 4 4 88 88 9i 9i 9i 9i 3 z 92 98 98 98 20 82 88 89 4 89 9i 92 39 9° 92 93 f 96 96 96 96 96 96 96 96 71 7 1 9i 9i 92 92 92 92 26 26 88 88 90 90 90 90 6s z I 65 .. Z 95 95 96 96 96 96 96 .96 67 67 83 83 85 85 86 86 35 35 88 88 9i 9i 9i 65 90 92 92 9i 3 9° 92 92 B . . ( •• I 9i 96 96 96 86 94 94 94 67 92 93 93 95 96 95 96 95 96 95 86 93 94 95 94 95 94 ' 95 67 70 92 90 93 9 C 93 90 84 3 93 93 93 Bw. . C 93 92 94 93 94 95 94 95 86 85 90 94 90 94 90 94 87 78 95 87 96 88 96 88 86 92 93 93 Untreated. > 93 92 94 93 94 95 94 95 86 85 90 94 90 94 90 94 87 78 95 87 96 88 96 88 z 3 86 92 93 93 86 94 94 94 70 99 99 99 9i 97 97 97 Controls . . ' . 9i - 88 97 97 97 97 97 97 86 97 97 97 88 85 97 95 97 95 97 95 •84 97 97 97 84 95 95 95

Table III. Seed placed in Germinators Twenty-eight Days after Treatment.