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are obtained, and when chess only is sown only chess is obtained. It has been shown further that in order to obtain seed from chess, chess must be sown the pre

ceding fall. When sown in the spring it does not produce seed for
the same reason that winter ?ye and winter wheat do not. It is not
found, therefore, in any but fall sown crops, and is less abundant in
rye than wheat, because of the greater hardiness of rye as compared
with wheat. The above habits are sufficient to explain the abun-
dant development of this plant in wheat which has been injured by
winter killing or by the Hessian fly when the sowing of clean seed
has not been continuously
practiced. The introduc
tion of chess seed in the
grain seriously injures its
market value, as the chess
must be removed before
the wheat is ground. The
machinery for this purpose
in large milling establish.
ments has reached great

perfection. Hackel says Chess.

that flour containing an ad(One-fourth

mixture of chess will be dark natural size.)

colored, remain moist and is narcotic. 1 Chess can be removed rather readily from the seed wheat by the ordinary fanning mills. When wheat is treated for smut, if the grains arestirred in the solu tion, any remaining chess seeds will come to the surface and can be skimmed off.

140. DARNEL.-Darnel belongs to the same tribe of grasses as wheat, to the same genus as perennial and Italian rye grass. Unlike these grasses, however, it is an annual. It occurs in grain crops of Europe and is also reported occurring in wheat fields of California, where it is known as chess. This plant is supposed to be the “tares” spoken of in the Bible. Like chess it is said to contain a narcotic Cockle. (One-fourth natural size ) principle which causes eruptions, trembling and confusion of sight in man, and in flesh-eating animals, and very strongly in rabbits, but does not affect swine, horned cattle or ducks.2 Darnel may be removed from wheat intended for seed by the same method as chess.

1 The True Grasses, p. 168.

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141. COCKLE.--Cockle is a widely and anciently distributed weed of the wheat field, belonging to the pink family (Caryophyllaceae). It grows from one to two feet high and is readily distinguished by its large pink blossom. Its seeds are black, angular, kidney-shaped, one-half to one-eighth of an inch across, marked with spiny reticulations arranged in rows around the curved side of the seeds. They are quite injurious to flour, and as they are readily seen in the grain, reduce the commercial value of the wheat. They are so near the size and weight of wheat grains as to be removed with difficulty. They may remain in the ground several years without germinating. As the plant is rather conspicuous and its number usually not rela. tively large, they may be pulled from the growing wheat.

142. WILD GARLIC,—This weed is sometimes found in the wheat fields of eastern United States. It grows one to three feet high and bears a cluster of bulblets

Wild garlic. (One-fourth natural size.) in place of seed. When these bulb

lets are ground with the wheat the flour is spoiled. Careful screening will remove the bulblets from the wheat. If the land is badly infested, it should be put into cultivated crops for at least two years.

143. WHEAT-THIEF.—This winter annual is also known as bastard alkanet, corn gromwell, redroot, pigeonweed. It grows six to twelve inches high and has narrow rough hairy leaves. It bears a large number of inconspicuous whitish flowers in a leaf cluster in March and April. The seeds are hard and stony, dark. one-tenth of an inch long, roughened, conical with a narrow base, and borne in fours in the axils of the leaves. The plant is very

hard to destroy, without destroying the wheat crop, which may Wheat-thief.

in some cases be advisable. It is probably less of a pest to the B, seed enlarged. wheat than it is to the subsequent meadows Badly infested (After Selby.) fields should be put into cultivated crops.

144. Wild MUSTARD.-There are two . Austards, black mustard (Brassica nigra, II..) Koch) and wild mustard or charlock (B. sinapistrum L.) found growing in spring sown cereals, of which the wild mustard is the most common. It is so common in spring wheat that the seed has become a by-product of flouring mills. The mustards are tall prickly plants with large leaves and bright yellow flowers. The wild mustard is distinguished from the black mustard on account of its long knotted pod being a stout two-edged beak. Seeds are dark brown to black, commonly spherical, one-twentieth of an inch in diameter, slightly granular-roughed. It has been found that by spraying wheat or oat fields with a three per cent solution of copper sulphate (about ten pounds to the barrel, or forty gallons, of water) at the rate of fifty gallons of solution to the acre, the mustard may be killed without injury to tie cereal.l The treatment is most effective if made in clear bright weather.

145. Fungous Diseases. — The more important fungi which attack the wheat plant are given below:

(1) Rust (Puccinia graminis Pers. and P. rubigo-vera (D C.))

(2) Wheat scab (Fusarium roseum Lk.)

(3) Loose smut (Ustilago tritici Jensen.)

(4) Stinking smut (Tilletia foetens B. & C.)

Another little studied fungus causes rather conspicuous dark spots upon the glumes of wheat, and has been given the name of “glume spot.” There is no known remedy.

146. Rust.-The rusts of wheat in the United States belong to two closely allied species, black stem rust and orange leaf rust, only the latter of which it is believed can pass the winter in the wheat plant. There are two stages of rust found on the wheat plant: (1) the red rast, caused by one-celled spherical uredospores, which commonly does not survive the winter, and (2) the black rust, caused by elongated two-celled teleutospores, which may

pass the winter' upon the ripened plant. It is believed The black rust on wheat

that the rust plant may enter the wheat plant at the

time of germination, or later if opportunity offers. The loss caused from rust is difficult to estimate, but it is undoubtedly very large. It is encouraged by hot moist weather during the ripening period. There is no

1 Cornell Bul. 216 (1904), p. 107. 2 P. rubigo-vera (D C.)

imown remedy. A great deal of study has been given to the discovery or production of rust proof varieties of wheat, with as yet little if any success.

147. Wheat SCAB.—The scab fungus is believed to be the conidial stage of a fungus which in its ascigerous stage is called Gibberella saubinettii (Mont.) Sacc.

The fungus attacks the glumes, causing dead sections of the spike, whose brown color is in striking contrast with the green healthy glumes. At times the whole spike is destroyed. It may be identified by the pink incrustations at the base of the dead glumes and covering the rachis.

Usually the losses are inconsiderable, although under conditions favorable to the fungus, it may amount to ten per cent or more. There is no remedy known, but where wheat is to follow scabby wheat the burning of the stubble has been recommended.1

148. Loose SMUT.-This fungus belongs to the same genus as the smut so commonly found on maize. The spores adhering to the grain germinate and enter the young wheat plant through the sheath of the first leaf. The fungus grows within the wheat plant without external manifestation until the wheat plant is about to flower, when the whole spike except the rachis is reduced to a mass of black smut spores.

The loss from loose smut is rarely large, although as high as eight per cent has been reported. The remedy is known as the modified hot water treatment and is as follows: Wheat spike with Soak the seed grain for four hours in cold water, let stand

scab: Upper por

tion has been de. for four hours more in the wet sacks, then immerse for

stroyed by the five minutes in water at a temperature of 133° F.; then dry

pink fungus. One. and sow.8 Since this treatment injures the germinating

half natural size, power of the seed, one-half more seed per acre is required. (After Selby.) The purchase of non-infected seed is also to be recommended.

149. STINKING SMUT.-Stinking smut is closely allied to the loose smut of wheat, in form and habit, although differing from it in the character and extent of its injury. It affects only the grains, which are considerably enlarged, the interior being converted into blackish, offensive smelling masses of spores, which, when they find their way into the flour, make it unfit for food. The glumes being unaffected, the disease often escapes observation until after the grain is threshed. Losses from this smut are rather general and often considerable, amounting in some instances to at least forty per cent, which, practically speaking, ruins the crop.

Any one of the following remedies has been found effective:

(1) Hot water: Place seed in any bag or basket which will readily admit water and immerse for ten minutes in hot water at 133° F.; then cool quickly by immers ing in cold water or by stirring thoroughly while drying.

1 Ohio Bul. 97, p. 42. 3 Ohio Bul. 42, p. 93. 8 Ohio Bul. 97, p. 60.

ired.

(2) Blue stone or copper sulphate: Immerse for ten minutes in a solution of copper sulphate at the rate of one pound to five gallons of water. Allow to stand for ten minutes in bag or basket to drain; then spread and dry. Or the seed may be sprinkled at the rate of one gallon of the solution to four bushels of the grain, sprinkling and stirring until thoroughly wet. At the end of an hour dry.

(3) Formalin: Treat seed by sprinkling or immersion for thirty minutes with a solution of one pound of formalin (forty per cent solution of formaldehyde) to fifty gallons of water.

In all treatments it is desirable first to stir seed into a tub of cold water and skim off the smut balls which rise to the surface. After treatment, the drying may be hastened by using slaked lime, but the lime is not essential.

150. Insect Enemies of Growing Wheat.—More than one hundred species of insects are known to feed upon the growing wheat plant, but very few are sufficiently injurious to be of economic importance. These few,

however, do enormous damage. Stinking smut. Single grain The chinch bug has been estimated much enlarged on the right. (After Kellerman.)

to cause a loss of over a hundred

million dollars to wheat alone in the United States in a single year."

The five most important insect enemies of wheat are as follows:

(1) The chinch bug (Blissus leucopterus Say.)
(2) The Hessian fly (Cecidomyia destructor Say.)

The wheat bulb-worm (Meromyza americana Fitch.)

The wheat midge (Diplosis tritici Kirby.) (5) The wheat plant-louse (Nectarophora cerealis Kalt.)

Of the above, the chinch bug and the Hessian fly are by far the most destructive, although the others frequently do considerable damage. Among the wheat insects of secondary importance

1C. L, Marlatt: The Principal Insect Enemies of Growing Wheat. U. S. Dept. of Agr., Farmers' Bul. 132, p. 6.

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