A similar spray, but with only 1 1/4 gallons of mineral oil in a 25-gallon lot, can be applied to the entire plants to reduce "budworm" damage by the earworm and fall armyworm to sweet corn before tasseling and silking.

THE CORN FLEA BEETLE causes direct injury to field and sweet corn and also is a carrier of the destructive bacterial wilt (Stewart's disease) of corn. This shiny black beetle is not much larger than a flea and jumps like one when disturbed. It is especially injurious to very young sweet-corn plants, which it often infests in great numbers. Experiments have indicated that it can be readily controlled in home-garden plantings, with attendant reduction of the wilt disease it carries and material increase in yields, by applying a dust containing 1 or 2 percent of DDT to the young plants. Good control also has been obtained in home gardens with a light application of a fine, mistlike spray containing DDT applied with a small plunger-type hand sprayer. The spray is made by thoroughly mixing 6 tablespoonfuls of a ready-made emulsifiable liquid concentrate containing 25 percent of DDT (usually obtainable in seed stores) with 1 quart of water. The spray may burn the plants more or less if applied so heavily as to leave droplets on them. One or two additional applications may be necessary if the plants become reinfested.

Some of the other new insecticides tested against the flea beetle on young sweet corn have shown considerable promise. In one trial on 8 acres of sweet corn plots, very good control was obtained by applying a concentrated solution of DDT as a very fine mist with a power blower at the rate of 2 pounds of DDT per acre. This treatment did not injure the plants.

THE ALFALFA CATERPILLAR could be controlled very easily by treating the infested stand with about one-fourth pound of DDT per acre in a dilute dust or spray if it were not for the residue problem. Even with such a light dosage, tiny amounts of DDT remain in the hay and appear in the milk, eggs, and meat of animals to which the hay is fed. The use of DDT on alfalfa therefore can be recommended only where the crop is being grown for seed; the threshings should not be fed to dairy animals, poultry, or meat animals that are being finished for slaughter.

The California State Extension Service in 1951 recommended methoxychlor sprays, applied at the rate of three-fourths pound of the active ingredient per acre for the control of the alfalfa caterpillar. Methoxychlor does not cause a residue hazard when it is used at the dosages recommended herein on alfalfa grown for hay.

This velvety green caterpillar, which is nearly 2 inches long when full-grown and of importance only in the Southwestern and Pacific Coast States, is kept under control much of the time by its insect enemies and a, wilt disease. With their help, most of the losses it causes can be prevented by cultural measures systematically applied throughout whole communities. Alfalfa growers in some California districts have found it profitable to employ entomologists to watch their fields during the growing season and advise them concerning the application of measures for the control of the caterpillar and other alfalfa insects.

Good control has been obtained by University of California research workers from the experimental spraying of infested fields with laboratory-prepared suspensions of the virus that causes the wilt disease of the alfalfa caterpillar. This method appears promising.

SEVERAL SPECIES of Lygus, as I mentioned, often are abundant in alfalfa and greatly reduce the yield where the crop is being grown for seed. DDT and toxaphene have been found very useful in controlling them. Recommendations issued in 1951 by the Utah State Agricultural College are:

"1. Dust the alfalfa seed field when the plants are in bud stage, using 20 to 25 pounds of 10 percent DDT dust per acre. Or, spray the field, using at least 1.5 pounds of actual DDT per acre. Either treatment will eliminate lygus nymphs for the first 3 weeks and, in addition, will often keep the population so low during the rest of the seed period that a second treatment is unnecessary.

"2. If, 3 or 4 weeks after the bud stage treatment, lygus nymphs begin to become numerous, apply 20 pounds of 10 percent toxaphene dust per acre. Or, 1 1/2 pounds of actual toxaphene as a spray may be used if a spray treatment is preferred. Make the application when bees are not working in the field. Put on the dust or spray before 7 a. m. or after 7 P. m. If applied as directed, toxaphene is not too harmful to bees for use on alfalfa in bloom. Most other insecticides will kill many bees even though applied at night.

"Do not feed forage or chaff treated with DDT or toxaphene to dairy animals, animals being fattened for slaughter, or poultry."

IN ADDITION to the cultural method of controlling the alfalfa weevil I mentioned earlier, the new insecticides. have led to improvements in its control.

A new departure is to kill off the over-wintered adults early in the spring before they have had a chance to lay eggs for a new generation. This is done by applying 1.5 to 2 pounds of chlordane per acre in a spray when the first spring growth of alfalfa is only 1 to 2 inches tall. As little as one-fourth pound of dieldrin per acre applied in a spray at that time has given even better results and is now being recommended by State Agricultural Experiment Station and United States Department of Agriculture entomologists.

When seed is to be grown the additional weevil control needed is provided by the application of DDT for control of lygus bugs as already described.

In field plot tests promising results have been obtained with extremely small dosages of aldrin, heptachlor, lindane, or chlordane, but none of these chemicals can be used safely on alfalfa to be cut for hay.

When the crop is to be used for hay the grower may prefer to control the weevil by killing the larvae after they become abundant on the first cutting of the season. If so, for maximum benefit the crop should be treated before many of the plants have started to turn gray. A dust or spray containing 2 pounds of calcium arsenate, 1 to 2 pounds of methoxychlor, or one-fourth pound Of parathion per acre is then used.

Parathion-treated hay must be left at least 14 days before cutting. When calcium arsenate is used the crop should be allowed to stand at least 10 days.

If parathion is used it should be applied only by airplane or power ground machine, not with hand equipment, and in strict observance of the directions and warnings given on labels and otherwise by the manufacturer.

THE PEA APHID is a serious pest of alfalfa as well as peas. This little, pale-green plant-louse often multiplies to enormous numbers on alfalfa early in the spring and ruins the first hay crop of the season in one area or another practically every year. Before we had the new insecticides certain cultural measures of a preventive nature were the only known methods of control. Several of the new insecticides are useful in suppressing infestations when actually in progress. The use of DDT as already described for the control of lygus will give good control of the pea aphid.

Parathion may be used as a 1-percent dust at 35 to 40 pounds per acre, if applied by ground dusters. This dust should not be applied by airplane. Excellent control may also be achieved with 1 pound of wettable 25 percent parathion powder in 100 gallons of water per acre. Alfalfa that has been treated with parathion should not be cut or pastured for at least 14 days. Do not apply parathion to alfalfa fields in blossom.

Tetraethyl pyrophosphate (TEPP) is extremely toxic to aphids. One pint of 40 percent emulsifiable TEPP in 10 gallons or more of water is applied per acre. The spray should be used immediately after it is mixed because it loses its strength in an hour or two. It should be applied after 7 P. m. if the alfalfa is in bloom, in order to avoid killing bees essential to cross-pollination. Large fields may be treated by airplane when the wind does not exceed 4 miles an hour.

THE GARDEN WEBWORM may become extremely abundant on alfalfa in late summer or early fall. This small, yellowish-green, black-spotted worm encloses the foliage in webbing, inside of which it feeds on the leaves. It can be controlled on alfalfa grown for hay by cutting the alfalfa as soon as it comes into bloom and the young shoots of the next crop have begun to appear on the plant crowns. Keeping weed growths cleaned up in fields, fence rows, and other uncultivated areas also helps to prevent the infestation of alfalfa from these sources. Where alfalfa is being grown for seed, however, prompt cutting is not feasible, and the use of an insecticide is the only alternative. The garden webworm is much easier to control with an insecticide if it is applied before the larvae become half-grown, because by that time they feed largely within their webs, which keep the insecticide off the foliage.

Newly seeded fields of alfalfa that become infested can be protected by dusting them with calcium arsenate at 10 pounds per acre or spraying them with 4 pounds of this insecticide in 100 gallons of water per acre.

Preliminary tests conducted by experiment station workers in Kansas and Oklahoma indicate that toxaphene is satisfactory for controlling this pest. Toxaphene is less toxic to bees than some other insecticides. Nevertheless, if the alfalfa is in bloom it should be applied only before 7 a. m. or after 7 p. m., when bees are not active in the field. Toxaphene as a spray at the rate of 2 pounds, or as a dust at the rate of 3 pounds, per acre should give adequate control if applied when the worms are small.

These insecticidal treatments are recommended for use only on alfalfa being grown for seed, where no part of the crop is to be used for feed or pasture.