insert is mild weather for four to six weeks after the wheat is planted. The spring brood reaches the adult stage during the latter part of April, during May and the first part of June.

The adult lays an oval-shaped egg, reddish in color, one-fiftieth of an inch long, on the inner side of the leaf blade. The egg hatches in a few days into a pinkish larva, soon changing to greenish, which finds its way down to the base of the leaf sheath. As the eggs in the fall are usually laid upon the youngest plants, the larvae are to be found somewhat under the ground, where they kill the diminutive culm. In this case the plant will be killed unless it has tillered, and some of the tillered culms escape. In the spring the eggs are laid on leaves somewhat higher up and the larvae will be found at the base of the first two or three leaves above the ground, where the injury causes many of the culms to fall before the grain is ripe. The puparium of the insect resembles in form and color a flaxseed. The pupal stage is therefore called the "flaxseed stage." When two-brooded, this insect passes the winter and the summer in the flaxseed stage.

Preventive measures are (1) late sowing, preferably delayed until after sharp frosts; (2) rotation of crops; (3) burning stubble; (4) sowing strips of wheat early as baits to be plowed under as soon as eggs have been laid. Of these the first two are to be especially recommended. The Hessian fly has many parasitic insects, otherwise it would probably make the raising of wheat impossible. Burning the stubble will destroy the parasites as well as the Hessian fly, which may not always be advisable. The destruction of organic matter also usually will not be desirable. In order to get the best results from late sowing it is advisable for farmers to act together, else the spring brood from the early sown wheat may attack the field which has escaped the fall brood.

There are no Hessian fly proof varieties of wheat, although those varieties which tiller most freely and have the stiffest and hardest culms will doubtless resist their attacks the best.

153. THE WHEAT BULB-WORM.-The wheat bulb-worm is a two-winged fly with essentially the same habits as the Hessian fly, except that it lives upon oats as well as several grasses, including timothy. The injury from the fall brood is almost identical with that of the Hessian fly; while the spring brood lays its eggs usually upon the upper leaf, thus causing the culm to wither and die above the upper node. While the Hessian fly therefore usually remains in the stubble after harvest, the wheat bulb-worm is carried from the field with the straw. The damage done by this insect is much less than that of the Hessian fly, for which it is doubtless frequently mistaken.

154. THE WHeat Midge. The wheat midge is also a two-winged insect. About the time the wheat is in the flower, the adult lays its eggs singly or in clusters to the number of ten upon the glumes of the wheat spike. The larvae suck the milky juice from the young grains, causing them to shrivel. They impart their orange-yellow color to the blighted spike. The insect is probably third in the injury to the wheat plant, but unlike the chinch bug and the Hessian fly, it thrives best in moist weather. The larvae enter the ground after about three weeks and pass the winter in the pupal stage. Many, however, are still in the

spikes when harvested, and are believed to survive in the straw for months without food or moisture.

Preventive measures are (1) the burning of chaff and screenings as soon as the wheat is threshed, and (2) deep plowing of stubble field to bury the larvae and pupae

155. THE WHEAT PLANT-LOUSE.-This insect appears on winter wheat in September, going through several generations in the early fall but doing little damage. If the spring is cool and moist, its natural enemies may fail to hold it in check and it may then cause considerable damage. Extensive damage has occurred only at rare intervals, as in 1861 and 1899.1 No effective remedy has yet been suggested.

Beetle and larva of the granary weevil. (After Chittenden.)

156. INSECTS INJURIOUS TO STORED GRAIN. While upwards of forty different species of insects occur in granaries, the following four species are the most injurious: 2

(1) The granary weevil (Calandra granaria L.)

(2) The rice weevil (Calandra oryza L.) (3) The Angoumois grain moth (Sitotroga cerealella Oliv.)

(4) The wolf moth (Linea granella L.) The first two are beetles and the last two moths. The larvae of the first three live within the grains, as do the adults of both weevils. This adds very much to their injurious effects, to the ease with which they may be distributed, and the difficulty of eradication. All breed more rapidly in warm than in cold weather and consequently do their greatest damage in the southern sections of the country, where they cause enormous losses.

The simplest and best remedy is the use of bisulphide of carbon at the rate of one pound to one ton of grain or in empty rooms for every 1,000 cubic feet.

Adult and larva of the Angoumois grain mɔth. (After Chittenden.)

There are a number of insects injurious to flour. The Mediterranean flour moth (Ephestia kuehniella Zell.) has recently become a most serious pest, requiring the adoption of extensive precautions in flouring mills to guard against its ravages.

II. HARVESTING AND PRESERVATION.

157. Date of Harvesting.-The wheat harvest of the United States begins in Texas in May and ends in the Dakotas in August. In California the harvest begins about June 1st and

1 U. S. Dept. of Agr., Farmers' Bul. 132, p. 24.

2 For a description and life history of these insects see U. S. Dept. of Agr, Farmers' Bul. 45.

lasts till August 1st. Everywhere east of the Great Plains. wheat is cut as soon as or a little before it is ripe, and the harvest extends on any one farm not longer than two or three weeks, the wheat being cut as fast as it is ready. In California, where there is no danger from rain, the harvest extends for many weeks after the wheat is ripe, some of it standing even ten weeks after it is ripe enough to cut. The only damage done to the standing wheat in this section is by occasional sand storms. he type of wheat usually raised is the club or square head, whose short culms prevent it from lodging.

The calendar of the wheat harvest of the world is given by Edgar as follows:

"In January, Australasia, Chili and Argentina; in February and March, East India, Upper Egypt; in April, Lower Egypt, Asia Minor and Mexico; in May, Algeria, Central Asia, China, Japan and Texas; in June, Turkey, Spain, southern France, California, Tennessee, Virginia, Kentucky, Kansas, Utah and Missouri; in July, Roumania, Austria-Hungary, southern Russia, Germany, Switzerland, France, southern England, Oregon, Nebraska, southern Minnesota, Wisconsin, Colorado, Washington, Iowa, Illinois, Indiana, Michigan, Ohio, New York, New England, eastern Canada; in August, Holland, Belgium, Great Britain, Denmark, Poland, western Canada, the Dakotas; in September and October, Scotland, Sweden, Norway, North Russia; in November, Peru and South Africa; in December, Burmah and Argentina." 1

158. Stage of Maturity on Yield. The usual practice in the eastern half of the United States is to cut when the straw begins to turn yellow and the grains are in the dough, soft enough to be easily indented with the thumb nail and hard enough not to be easily crushed between the fingers. Investigations indicate that there is a continuous increase of the plant during its growth until the plant is entirely ripe. There is a continuous increase in the weight of the grain from the time it is formed until it is hard and dry. The increase in weight of grain is most rapid up to the time when the grain can be crushed between the thumb and finger. The increase seems to be decided and of economic importance up to the time when the grains indent but 1 Wm. C. Edgar: Story of a Grain of Wheat (1903). p. 191.

do not crush under the pressure of the thumb nail. After that time the increase is slight. The indications are that if allowed to stand beyond the period of full maturation, a slight decrease in the actual substance of the grain may take place. This is explained by Deherain on the ground that the seed continues to respire, thus giving off carbon dioxide.

159. Influence of Ripening Upon Composition.-In general, there is a decrease in the percentage of ash, nitrogen and fiber as the grain ripens, due to the increase in carbohydrates other than fiber. This is due to the endosperm developing later in the growth of the wheat. The germ develops first, and later, when the endosperm develops, the percentage of ash and nitrogen becomes less, although the actual amount may remain the same, or, as is probably the case, may increase. The changes in composition after the grain has reached the dough stage appear to be very slight.1

While the stage of maturity of grain through the ordinary range of wheat harvest does not affect materially the quality (composition) of the grain, climatic conditions which affect the full maturity of the grain may materially modify the quality. The higher percentage of nitrogen in the spring wheat is probably due, in part at least, to a lack of full maturation. (74) The per cent of nitrogen decreases somewhat in the straw up to the dough stage. The per cent of crude fiber increases in the straw throughout the ripening period, while there are corresponding decreases in the other carbohydrates.

160. Influence of Shocking.-There is always danger of overripe grain shelling out in the harvesting, and there is also danger of lodging. It is not good farm practice, therefore, to delay harvesting until wheat is entirely ripe. Investigations have proved beyond question that at the early stages of seed formation a considerable transfer of material from the straw to 1 Mich. Bul. 101, p. 8.

the grain may occur after cutting, when the wheat is placed in a condition similar to the shocking and capping of bound sheaves.1 Prompt shocking and capping, therefore, facilitate the completion of the ripening process. Where it is necessary to cut the wheat quite green, it is important that the sheaves should not be left long on the ground exposed to the hot sun

161. Method of Shocking.-The sheaves may be put in long shocks by placing pairs of sheaves in a row, about a dozen bundles to the shock, or preferably in round shocks with caps, twelve to sixteen bundles to the shock, depending upon the size of the bundles, the stage of maturity and the amount of green weeds. In building a shock of twelve bundles, place three pairs in a row, then place two bundles on each side, making ten bundles. Now lay one bundle on the top, then take another bundle, break both ends of the bundle at the band, spreading the ends fan-shape, and lay this crosswise of first bundle. In some cases only one bundle is used, treating it as just indicated, and in other instances the caps are entirely omitted. Usually, however, capping with two bundles is to be preferred. In building a shock of sixteen bundles, place four pairs in a row, then three bundles on each side, and cap with two bundles. Both for efficiency and economy of time, two bundles should be handled at once, and care should be taken to place the bundles firmly on the ground. There is a knack in shocking that may be easily learned by practice, which adds greatly to the ability of the shocks to withstand wind storms

162. Methods of Harvesting-There are four types of power machines for harvesting wheat and other stored grain in the United States at the present time. They are: (1) the self-rake reaper; (2) the self-binding harvester; (3) the header; and (4) combined harvester and thresher. The hand cradle is still manufactured and used for harvesting small areas.

1 Ill. Buls. 11 (1890), p. 349, and 22 (1892), p. 119. Mich. Bul. 125 (1895), p. 34