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518. Weeds.--Perhaps the most serious menace to rice culture is the growth of weeds. This is especially true where rice is grown without cultivation, and where the water comes from streams which abound in weed seeds and readily disseminate them.
Dodson gives the following list of weeds which have proven most menacing to the rice fields : 1
(1) Red rice (Oryza sativa var, rufipogon).
(2) Large indigo, straight indigo, coffee weed, senna, long podded sesban (Sesban macrocarpa Muhl.).
(3) Curly indigo, sensitive joint vetch (Aeschynomene virginica (L.) B. S. P.). (4) Tadpole grass, wiggle-tail, spear grass (Rhynchospora corniculata A. Gray) (5) Bull grass (Panicum agrostidiforme Lam.). (6) Smart weeds (Polygonum, especially P. acre H. B. K.). (7) Turtle back (Commelina virginica L.). (8) Alligator head (Diodia teres Walt. and Diodia virginiana L.). (9) Bird's eye (Scleria—several species). (10) Morning glory (Ipomoea tamnifolia). (11) Water grass (Paspalum fluitans Kunth. and P. virgatum) (12) Moss weeds.
By far the most important and most serious one of these weeds is red rice. (505) Few rice fields are free from it. By many planters red rice is believed to result from volunteer plants growing from seeds of the cultivated white rice. It seems, however, to be demonstrated that it is a distinct strain, and that red rice can be obtained only from the seed of red rice. The two types readily cross, and the results of the Louisiana Station indicate that the red rice has the greater influence where crossing takes place. 2
Next to red rice in importance is the large indigo weed, both because of its abundance and large size, the plant often growing to a height of fifteen feet, while the stems sometimes attain a diameter of two to three inches. Like the curly indigo, it is a leguminous plant.
The alluvial lands are especially liable to become infested with weeds, so that as a rule after two or three successive crops are raised, the soil must be devoted to a cultivated crop or allowed to grow up with weeds for one or two years. The weeds that are injurious to the rice plant are water weeds. If the land is drained, the field will grow up to dry land weeds and largely exterminate the water weeds, when the lield can again be cultivated in rice. This is considered by some to be good pracrice, since the land retains its fertility and the finest crop of rice is the first crop
after such treatment. One of the reasons for flooding is to prevent the growth of weeds, but those which germinate quickly are enabled to keep even or ahead of the rice and thus escape injury from flooding. In some cases, where the weeds get ahead of the rice, especially those weeds (not grasses) which grow from the tip, the fields are mown, which checks the weeds, while the rice, but little injured, shoots ahead, when the field can be flooded and weeds killed. This is not effective for weeds of the grass family, because the habits of growth are the sam: as in the rice. Mowing stubble and burning it soon after rice has been harvested is a rather effective method of killing weeds; but the exposure of the bare soil to the rays of the sun and the lack of vegetation bring about physical, chemical and biological conditions that are undesirable. Mowing and burning late in the fall, after weeds have gone to seed, is, therefore, more commonly practiced, but is not so effective in destroying weeds, since the moist soil protects many from burning. This late burning is sometimes followed by early spring plowing to induce germination of weeds, when they may be destroyed by cultivation before seeding. This results in late seeding,
which is objectionable. (514) In the alluvial lands the weeds are pulled by hand two or three times during the growth of the crop.
519. FUNGOUS DISEASES. — The rice plant is sometimes attacked by a smut (Tilletia corona Serib.), occurring on several grasses. It is very similar to the stinking
smut on wheat. While not definitely proven, Three -spikelets of rice; outer glumes it is believed that the treatment recommended shown at base. A, normal mature for stinking smut on wheat would be efficaspikelet with healthy grain enclosed; cious. (149) The smut has not been widely B, grain affected with rice smut shown reported, but in some instances it has apparat e; C, grain more completely de- ently done considerable damage. The kernel stroyed with rice smut shown at e.
of the rice is filled with a mass of black (After Anderson.)
spores, as in the case of wheat, but it is not usually abnormally large. The cause of blast or blight, a premature death of the plant or only the head, is not fully understood.
520. INSECT ENEMIES.—The number of insects attacking rice are not many, nor are their injuries extensive or ordinarily serious. The principal one is the water weevil (Lissorhoptrus simplex Say). The adult is a small gray beetle, which makes its appearance in April and May and feeds upon the leaves of the young rice plant. The insects soon breed, and being semiaquatic in habit, the female lays its eggs among the roots of the plant. The eggs hatch in July and August into white, legless grubs, which feed upon the roots of the plant, where the principal damage is done, and which may be detected by the yellowish appearance of the plants, often in clumps. The presence of water seems necessary to the larvae; hence the removal of the water and drying the land at the proper time is recommended, although this practice is injurious to the rice.
The rice grub (Chalepus trochypygus Burm.) is a scarabaeid beetle, the larva of which feeds upon the roots of upland rice. Water kills it.
The rice stalk borer (Chilo plejadellus Treuck) is a crambid moth, the larva of which bores into the upper part of the stems, and in part, at least, is believed to cause what is known as “white blast.” If it becomes serious, which is seldom, burning of stubble is recommended. The chinch bug (151) is sometimes injurious to rice fields, and the fall army worm (Laphygma frugiperda Sm. and Abb.), when numerous, may become injurious.
521. BIRDS.-In some sections, the rice bird, reed bird or bobolink (Dolichonyx oryzivorus L.) is one of the most serious obstacles to the culture of rice. It attacks the rice fields during the ripening period, being especially injurious when rice is in the milk. The rice bird is particularly injurious in the South Atlantic States, where it is common to hire men and boys, called “bird minders,” to scare away the birds, the common method being that of shooting off guns loaded with powder, but usually not with shot, since the latter injures the rice.
The English sparrow (Passer domesticus L.) has become a serious pest in parts of Louisiana, both to the ripening grain and while it is in the shock. The best prevention for the latter is prompt threshing, and, where this is not practicable, stacking.
Many species of other birds occur in large numbers in the rice districts, drawn there by the abundance of pala table food, the most numerous of which are the various species of blackbirds. While these birds eat some rice, they gain most of their sustenance from the grain that has fallen to the stubble and from weed seeds ; and are, therefore, believed to be beneficial rather than injurious.
1. HARVESTING AND USE.
• 522. Time of Harvesting. — It requires from four to six months to mature a crop of rice. The date of harvesting in the United States varies usually from August to October, the early seeding and early harvest being preferred. The price realized generally is greater on account of lack of competition from foreign rice. The stage of maturity is probably more important with rice than with any other cereal crop, because of its marked tendency to shatter, and because of the process of milling, which requires grains which are not easily broken. Uniformity of ripeness is also essential; hence the desirability of having all portions of the field covered with as uniform depth of water as practicable. To get the best results, it is usually considered desirable to harvest when the grain is in the stiff dough and the straw somewhat green.
523. Method of Harvesting. In the South Atlantic States and along the Mississippi River the sickle is still used, although not exclusively. In this case the sheaves are laid upon the stubble to partially dry when they are bound. In some cases the bundles are put into the shock, where they remain until drawn to the thresher; while in other cases they are drawn from the field and placed in stacks, or in still other cases the grain is stacked loose. Heating in either shock or stack is liable to take place.
“A rough method of measuring the temperature of the rick is by inserting a stake into the mass at either end. The stakes are examined daily by being crawn out suddenly, and if the inner point is fund to be too hot to hold in the hand, the rick must be pulled down, aired and built afresh; but if the stake is not too hot to hold, the rick must be left undisturbed.” 1
In the prairie regions the self-binding harvester is used. (164) Slow curing in the shade gives best milling rice. Shocks should be placed upon dry ground lengthwise east and west, and caps should be put on with heads towards the north in order to avoid the sun as far as may be.? (161)
524. Threshing.-Rice is now universally threshed in the United States with the ordinary threshing machine. The itinerant machine (167) is used in the South Central States, but in the South Atlantic States stationary threshing machines placed under cover are employed, when they are referred to as threshing mills. Some care is required to adjust the machine so as not to break the grains.
525. Use.—The chief use of rice is for human food. It is estimated to enter into the dietary of more than one-half the population of the world, and is said to form more than fifty per cent of the subsistence of the people in some parts of Asia. In China it is used largely in connection with the fish raised so abundantly in their numerous waterways, and also with the soja bean (Glycine hispida Maxim.), which, on account of the high per cent of protein and fat in this bean, makes a diet resembling closely one made of meat, potatoes, bread and butter. Rice is usually eaten whole or in soups; it is seldom made into any form of bread or pastry, for which it is not well adapted, on account of its low percentage of gluten. It is sometimes, however, mixed with wheat flour. Rice is largely used for the manufacture of starch, and its lower grades are also used in the production of malt and alcoholic liquors. (465) The lower grades are so extensively used for this purpose as to be known to the trade as brewers' rice.