Bulletin No. 116 June, 1931Montana State College, Extension Service, J. C. Taylor, Director, CooperativeExtension Work in Agriculture and Home Economics. Montana State Collegeand Uni~ed States Department of Agriculture, co-operating. Distributed infurtherance of the Acts of Congress ~ay 8 and June 30, 1.914. .~

CONTROL OF SMUT IN WHEATAND OTHER SMALL GRAINS

ByH. E. Morris, Extension Plant Pathologist

Waldo Kidder, Extension Agronomist

Smuts cost the farmers of Montana many thousands of dollarseach year. In 1930, stinking smut of wheat alone caused a lossof approximately $750;000, due to decreased yields and to alower price per bushel. This loss and also that due to the smuts

{..:Fig. 1. Smutted and normal heads of wheat. The head at the left ,is atypi:cal head affected with covered or stinking smut, The next, head IS ahe'althy head. The two heads on the right show two stages of the loosesmut in wheat. (-Courtesy,D. S. Dept. of Agr.)

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of oats, barley and rye may be largely prevented by adoptingthe methods of seed treatment described in this bulletin.

What Is SmutSmut is produced by a small parasitic plant, mould-like in

appearance, belonging to a group called fungi (Fig. 2). Smutlives most of its life within and at the expense of the wheatplant. The smut powder, so familiar to all, is composed of myriadsof spores which correspond to seeds in the higher plants. Inthe process of harvesting and threshing, these spores are dis·

Fig'. 2. Comparison in size between: a, fine sand; b, very fine dust;c, spores of the fungus causing l'ose rust (Phragmidium); d, spores of thewheat-rust fungus (Puccinia); e, spores of the fungus. causing apple scab(Venturia); f, spores of oat smut (Ustilago); g, spores of blue mold offruit (Penicillium) j h, spores of potato dry rot fungus (Fusarium). Mag.nified 110 times.

I

CONTROL OF SMUT IN WHEAT AND OTHER SMALL GRAINS 3

tributed, many of them adhering to the wheat. Conditionsfavoring the germination and growth of the wheat are favorableto the growth of the fungus. The spores germinate at the sametime as the wheat. If the smut fungus comes into close contactwith a young wheat seedling, it enters the tissues of the seedlingand thereafter grows within the wheat plant. About the timewhen the wheat plant should normally form grain, the fungusproduces spores, the familiar black smut powder (Fig. 3) whichtakes the place of the kernals of grain.

Kinds of Smut

Grain smuts may conveniently.be divided into three classesbased upon their methods of attacking their hosts. First,· smuts

Fig. 3. Normal and smutted kernels of wheat. Smut balls shown atbottom when broken release the black powder which is composed of thespores (seeds) of the smut plant. Each smut ball contains thousands ofthese spores or seeds which may infect the wheat unless proper seed treat­ment is given. ('Courtesy, U. S. Dept. of Agr.)

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including the stinking smut of wheat which cause infection onlyin the seedling stage are commonly called covered smuts. Inthis class the infection may develop from the spores (smut seeds)adhering to the grain kernel or from the spores in the soil. Thisclass includes the stinking smut of wheat, the covered smut ofbarley and the oat smuts.

Second, smuts, including the loose smut of wheat and theloose smut of barley, which infect only flowers. In this classthe fungus is inside the seed. .

Third, smuts such as corn smut which may affect any younggrowing part of the plant. Seed treatment is useless for con­trolling this class of smuts. -

Different Smuts For Each Crop

There are different kinds of smut, each peculiar to the plantin which it grows. Wheat smut will not grow in oats or barley,oat smut will not grow in wheat or barley, and barley smut willnot grow in wheat or oats.

Two Smuts of Wheat j.

There are two -smuts of wheat, the stinking smut or bunt .which is the most serious, and the loose smut.

Loose smut is sometimes mistaken for stinking smut. Loosesmut appears about the time the heads are emerging from the iboot and produces a black, loose, fluffy mass of spores (smut Ilseeds) which are soon blown away by the wind leaving a barestalk (Fig. 1). !I!his smut may be controlled only by treatingseed with hot water.

The characteristic symptoms of stinking smut are a bluish­green color in contrast to a normal green color of the wheat headsin the dough stage; the stems of infected plants are often shorter ,f.

than normal ones; the presence of smut balls in the infected head(Fig. 1 and 3), and the stinking, smutty odor.

Each smut ball contains numerous spores or "seeds" of thefungus: Each spore is capable of infecting a seedling wheatplant, and there are about as many spores in each smut ball asthere are kernals in five or six bushels of wheat. In threshing,many of these smut balls are broken and the spores or "smut

CONTROL OF SMUT IN WHEAT AND OTHER SMALL GRAINS 5

dust" coming like smoke from the combine or thresher are dustedover the good wheat or returned to the soil.

The symptoms described for the two smuts of wheat arequite characteristic for the loose smuts and the covered smutsof other grain.

Conditions Affecting Smut Infection

The effectiveness of seed treatment may vary from year toyear in the same locality. In explaining the occasional poorresults of recommended treatments in controlling stinking smut,one must consider this disease in its relation to soil temperatureand soil moisture. It is often stated that the date of plantingis closely as,sociated with the amount of smut in the resultingcrop. This is because soil temperature. greatly influences infec­tion by stinking smut.

The infection of smut takes place in the very young wheatplant before the first leaf emerges. Therefore, a quick emergenceof the wheat plant after it is planted is advantageous becauseit lessens the chances of infection. With enough soil moisture,it takes from 12 to 22 days for the wheat plant to emerge whenthe soil temperature is between 41-50° F., while it takes onlyfour to eight days when the soil temperature is from 59-68° F.

Wheat should be planted about the time recommended forthe locality, but under the most favorable conditions regardingsoil moisture and soil temperature.

Control of Grain Smuts

Seed treatments which have proved very effective in reducinglosses from various smuts are now being used by the most suc­cessful grain growers. Although information about seed treat­ment has been widely distributed, losses caused by smuts con­tinue to increase.

Losses in winter wheat can be greatly reduced and lossesin spring wheat practically eliminated by strictly following thesepractices each year:

First, by the use of only carefully re-cleaned seed grain.

6 MONTANA EXTENSION SERVICE

Second, by proper use of the best seed treatment for thekind of grain.

Third, by more careful tillage.Fourth, by more attention to planting grain when the soH

is fairly warm and moisture conditions are favorable.All seed grain should be carefully re-cleaned over a good

fanning mill before the seed is treated. :Such cleaning shouldremove all of the smut balls, all shriveled and broken seed, allweed seed, and other trash.

The use of carefully cleaned and properly treated seed reducessmut losses and aids in producing cleaner and more profitablecrops.

Copper Carbonate Treatment For StinkingSmut of Wheat

Winter Wheat: Use two to four ounces of 50 per cent coppercarbonate to each bushel of re-cleaned seed. Mix until eachkernel is thoroughly coated.

Spring Wheat: Use two ounces of 50 per cent copper car­bonate or two to three ounces of 20 per cent copper carbonate toeach bushel of re-cleaned seed. Mix until each kernel is thoroughlycoated.

The results of many tests have proven conclusively thatcopper carbonate when properly applied is as effective in con­trolling stinking smut of wheat as either the blue-stone or for­maldehyde methods of treatment formerly recommended. Thewet treatments can no longer be. considered practical.

Quality and Grades of ICopperCarbonate

The copper carbonate powder recommended for the treat­ment of seed wheat should be light and fluffy and light green incolor. It should be fine enough to permit 98 to 100 per cent of itto pass through a 200-mesh screen. Heavy, bluish and coarsepowders should be rejected. A good dust should feel smoothwhen rubbed between the fingers.

Copper carbonate is sold in two grades: pure or "50 %" coppercarbonate contains from 50 to 54 per cent copper, while extended

CONTROL OF SMUT IN WHEAT AND OTHER SMALL GRAINS 7

or "20 %" copper carbonate contains from 18 to 20 per cent.copper. Since copper is the active agent, tbe pure copper car­bonate is about two and one-half. times more concentrated thanthe extended product.

Directions For Using Copper Carbonate

"It is not the dust in the machine but the dust on the kernelthat counts." Each kernel of wheat should be thoroughly coatedwith the dust. This can not be done by shoveling, by attemptingto mix tbe grain and dust in the drill box, or by mixing the seedand dust on the floor with a rake.

The best results have been secured when the treatment hasbeen given with a power driven' continuous treating machine(Fig. 4), hence commercial power dusters are advocated fortreating large quantities of grain. There are on the market somepower machines of different types with a capacity of 30 to 150bushels or even 300 bushels per hour.

Fig. 4. IA commercial treating machine in operation. Note the drum. type, of, !Ilacl;Jine, the coppe,r carbonate container and the masks or respirators

. to' .protect the operators from inhaling the dust..

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8 MONTANA EXTENSION SERVICE

A home made duster, satisfactory for treating small quanti­ties of grain, may be made out of an old oi\ barrel for approxi­mately five dollars (Fig. 5).

-- ~F'"o..~ 0,;,,-'(' ~ F';~-". 30 T(;'lNS pE'"lf",vre

Fig. 5. A homemade treating machine.

Advantages of the Copper Carbonate Treatment .The advantages of this dust treatment are: it controls smut,

it causes no injury to germination, seed· can be treated duringspare time and stored until ready for use.

Effect of ,Coppel' Carbonate on the DrillCopper carbonate may cause the parts of the drill to Uset"

or to work hard. To avoid this trouble always rock the feedshaft gently with a wrench before starting the machine. Thedrill should be thoroughly cleaned and oiled before it is put awayfor the season. .

Do Not Inhale Copper CarbonateIf copper carbonate is inhaled it may cause nausea and

CONTROL OF SMUT IN WHEAT lA'ND OTHER SMALL GRAINS 9

headache. Seed should be treated preferably out-of-doors or ina well ventilated room. The use of respirators (Fig. 4) areadvocated where large quantities of grain are to be treated.

Formaldehyde Method for All Grains

The formula most commonly. used consists of 1 pint of for­maldehyde (37-40 per cent strength) in 40 gallons of water. Itmay be used in the following ways: . First, as a dip. Immersethe grain in the solution in loosely filled sacks for ten minutes.Remove' the sacks, let the excess material drain back into thevat and allow them to stand without opening from two to sixhours.

Second, by using the solution in a smut treating machineaccording to the instructions furnished by the manufacturer.

Third, as a spray. Sprinkle approximately one gallon of for­maldehyde solution on each bushel of wheat or about one and ahalf gallons on each bushel of barley. Shovel thoroughly until eachkernel is wet and cover the whole pile with sacks or canvas fromtwo to Six hours.

Formaldehyd.e Spray Method for Oats only

Add one pint of formaldehyde to one pint of water. As theoats are shoveled over, the solution is slowly added by the use ofa quart handsprayer or atomizer. After add~ng the solution thegrain is covered with sacks or canvas for four hours. If sowing isdelayed or if the oats are to be stored, the pile should be spread outand aired for one day. One pint of formaldehyde is sufficient totreat fifty bushels of oats.

Modifications of this method are sometimes used. The solu-. tion may consist of one pint of formaldehyde in 10 pints of water

or one pint of formaldehyde to 10 gallons of water. The treat­ment is carried out in the same manner except more solution isblsed.

Hot Water Treatment

For loose smut of wheat and loose smut of barley: I'Jlhesesmuts may be controlled by the use of the hot water treatment.

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This treatment is so difficult that it is better to buy clean seedwheat.

In special cases where it is desired to disinfect a particularstrain of seed, detaiied instructions will be given to the grower

\ regarding this treatment.

Organie Mercury Compounds

Many patented fungicides are on the market. Some of themare effective but are rather expensive. In general, they do notcontrol smut better than cappel' carbonate or formaldehyde.

Dry Grain Best For Threshing

Smut dockage and inoculation of wheat .often is reduced ifthe wheat is threshed when dry. Most of the smut is blownaway from dry wheat while smut spores stick to damp wheat.

Field Results of Seed Treatments in 1930 .

In cooperation with the Office of Cooperative Extension Workof the United States Department of Agriculture some field studieswere made in Montana and other northwestern states during1930 to determine the amounts of smut in the fields and to learnthe methods of seed treatment used. Fig. 6 shows the results.The spring wheat studies were made in Montana; the 'winterwheat studies in Montana, the Dakotas and Minnesota. Whilethese figures are for only one season they show conclusively thatproper'treatment gives good control of smut and point out thelack of control by poor methods of treatment. The coppercarbonate treatment was most effective.

This study showed the value of fairly early planting (aroundSeptember. 10th to 25th) of winter wheat, on summer fallowland. Spring wheat should be planted after the soil has become.warm.

Good clean seed, good seed treatment and good tillage willreduce smut losses to a minimum, and Montana grain growerswill profit greatly in securing better yields and higher prices.

C0NTROL OF SMU'f IN WHEATA:ND OTHER SMALL GRAINS 1J:~:!,.

:EFfECTIVENESS OF' SMUT CDNTRDL METHDOS

TR.EA'TMENTAvera'i,e PerCent Smut in Wheai

() R 8 10 12 I.e. 16 18 RIJ el 24-

50% Copper CarbonateI~Home made mixer

50% Copper Car~nateI~Commercial machines

Ceresari Wln~er Wheil.\Home made mixerformaldehyde r

Commercial machine jI

Blue ViI riol soa~ II

50% Copper Carbonate i• shoveled I

formaldehhde - ~rn~edand 5 ovele

20% Copper CarbonaieCommercial Machines

No treatment ~I

T.i:U:ATME:N..,.. I. i% 2r. 31 -4-:t Sf. BY. 7:< 8;< 97: lOA.'

50 %COl!I!er Ca.rIJonate ,.l1ac77il7e~m/xed

20% COjJjJer CtJroonate \-. flachine':"mix.edrormaldel£,de

I~I Sprin9 Wneat.t1achtne- /xed20% COlfer Carbonate

!~Home-made mixerCeresan

I~'Machine -mixedrormaldehyde

3prtnlrle:20% CONer C8rbontl.te- I

Shovel-mixed .._--..- . .. .. - ~ .. ~-....

N~ treatment . ~

Fig. 6.

Cereal Smut Ch~mical

SEED TREATMENTS FOR SMUTS

How Used Treatment

Wheat Stinking smut

Loose smut

Loose smut

Copper carbonate 52%Copper carbonate 20%Hot water

Hot water

2 to 4 oz. per bu.2 to 3 oz. per bu.129 0 F.

120 0 F

On winter wheat-Mix until each kernel is coatedOn spring wheat-Mix until each kernel is coatedModified method-1st, soak 4-6 hrs. at 68-85 0 F.

2nd, soak 1 minute at 120 0 F.3rd, soak 10 minutes at 129 0 F.4th, dip in cold water; spread

thin to dry.Single bath method-Soak 1 hr. and 35 minutes;

spread thin to dry.Oats Loose and

covered smutall varieties

Barley Covered and(six-row) loose smut

Barley Covered smut(two-row) loose smut

Formaldehyde

Formaldehyde

"'Formalin dustcompound(**Certain organicmercury salts)

Formaldehyde(**Certain organicmercury salts)

Same as barley 6-rowedHot water

1 pt, in 1 pt. water,for 50 bu. oats

1 pt. in 30 gal. waterfor 50 bu. oats

8 oz. per bu.

1 pt in 40 gal. water1 oz. in 3 gal. water

126 0 F

Spray with atomizer-cover 5 hrs.

Soak 30 minutes or sprinkle thoroughly andcover 2-8 hrs.

Mix until each kernel is coated. Sack and stand3 hrs.

Follow directions on package.

Soak 30 min. and cover 5 hrs. or soak for 2 hrs.Follow instructions on package.

Soak 4-6" hrs. at 68-85 0 F.; 1 minute at 120 0 F.;and 13 minutes, at 1260 F. Dip in coldwater, spread thin to dry.

Corn Smut No seed treatment No seed treatment Destroy affected parts and crop refuse; crop ro­tation.

Sorghum Covered ker­and Millet nel smut

Copper corbanote 52% 2 oz. per bu. Mix until each gemel is coated.

*This "compound was developed by the Ohio Experiment station and is sold under the trade name of "Smuttox."·"*There are several products of this kind on the market, under such trade names as Ceresan, Chlorophol, Uspulun,

etc.

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