Split half a million bushels of smooth or Canada field-peas are annually required for the produc tion of "split peas," which are used principally in making soups. The hulls, which are removed in the pro cess of manufacture, and the refuse peas are ground together to make "pea meal," which is sold as a stock food.
Canning.—The canning factories use the garden pea grown as a field crop, not the type known as field-pea. [The subject of canning is discussed in Part II of this volume.] The pods and vines from canning factories are often ensiled, or fed green.
Enemies.
Weeds.—The pea crop, as most others, encoun ters a number of rather serious obstructions to growth. As a rule, it is not seriously interfered with by weeds, as it starts quickly and makes rapid progress, thus smothering out most weed competi tion. If, however, the land is infested with the annual wild mustard (Brassica Sinapistrum), the crop may be seriously injured. Fortunately this weed may be destroyed when a few inches high by spraying with a solution of about twelve pounds of copper sulfate in fifty gallons of water, while the peas are not materially injured by the solution. This treatment is most effective if the spraying is performed on a bright, hot day. Young mustard plants are much more easily destroyed than those approaching bloom. An ordinary four- or six-row potato sprayer answers well for the work. The metal parts of the sprayer should be brass, as iron is actively attacked by the solution. (Page 118.) Insecls.—There are three insect enemies of the pea crop, each of which is very destructive at times : the pea weevil or "pea bug" (Bruchus fis orum); the pea moth (Semasia nitricana); and the pea louse or aphis (Nectarophora destructor).
The weevil is a brownish gray, active beetle, one-fifth of an inch long, which emerges from peas in autumn or in spring, leaving a small round hole. The egg is laid on the outside of the young pods and the grub, on hatching, eats its way into the pea. Here it undergoes its transformation, usu ally not emerging till the peas are sown the follow ing spring. The affected peas are much injured for seed and somewhat far stock-food. Fumigation of the seed stock with bisulfid of carbon is effect ive as a remedy so far as the seed is concerned, but the few beetles which emerge in autumn and hibernate in barns or fields prevent a complete riddance of the pest. In treating the seed it is
usually placed in tight vessels or rooms and ex posed for two or three days to the fumes of bisulfid of carbon. One pound of bisulfid is sufficient for about one hundred bushels of peas.
The pea moth, in the perfect form, is a small, slaty gray moth, three-eighths of an inch long. The moths, however, are seldom seen, the insect be ing observed by pea-growers when in the cater pillar state, and is usually called the "worm." They are small, whitish, slightly hairy caterpillars, when full-grown about half an inch in length, which live inside the green pods, attacking the peas by gnawing ragged-edged cavities into them and filling the cavities about them with excrement. This insect is very destructive in eastern Canada and in recent years has become abundant in Jeffer son county, New York. The injuries are most severe to late peas. Suggested remedies afford little relief except that by planting early and using early varieties the attack is usually escaped.
The pea aphis is a pale green plant-louse which clusters in enormous numbers at the tips of the shoots and sometimes over the whole plants of field-peas ; and it sometimes is found on sweet-peas and clover. These insects appear suddenly in large numbers and sometimes cause great loss over large areas of country. This species is very active and springs from the plant on the slightest touch. This trait has been used for their destruction by plant ing the seed in drills and using the cultivator to bury the aphids after they have been brushed from the vines.
Literature.
The first two references following have to do with the culture of peas, and the last two with pea enemies: Farmers' Bulletin No. 224, United States Department of Agriculture, Washington, D. C.; Soiling Crops and the Silo, Shaw, pp. 102-110 ; Yearbook, United States Deportment of Agriculture, 1898, p. 223 ; Delaware Experiment Station, Bul letin No. 49. [See, also, the gardening books.]