Some of the miticides recently put on the market by insecticide manufacturers have shown promise for use on alfalfa. For information concerning these the grower should consult his State agricultural experiment station.

THE POTATO LEAFHOPPER does much damage to alfalfa and peanuts and could as well be called the alfalfa or peanut leafhopper. It is a pale-green, soft-bodied, wedge-shaped winged insect only about one-eighth inch long when full-grown. It often becomes extremely abundant on these crops and sucks the sap out of the leaves, causing them to turn reddish yellow and die.

In experimental trials favorable results have been obtained with several of the new insecticides for leafhopper control on alfalfa and peanuts. On alfalfa excellent control was obtained with one-half pound of methoxychlor per acre in spray or dust form applied midway in the development of the crop.

On peanuts in Virginia, three applications of a dust containing go percent of sulfur and 1 percent of DDT gave good control of the leaf spot disease as well as the leafhopper. The first application was made about July 10 and the other two applications at 3-week intervals. To avoid possible residue hazards, the total amount of this dust applied during any one season should not exceed 80 pounds per acre.

SEEDLING PEANUTS are subject to injury by the tobacco thrips, an extremely small yellowish insect that becomes numerous within the folds of the young leaflets, causes them to crinkle, shrivel, turn black and die, and retards the early season growth of the plants. Several of the new insecticides, especially DDT, aldrin, and dieldrin, have given good control as dusts and sprays in experimental trials, and it is hoped that one or more of these can be recommended when more information has been obtained on dosages required and possible residue hazards.

SPITTLEBUGS have been abundant in the Eastern and North Central States. These insects produce little masses of white froth around themselves and the stems of alfalfa, clover, and other plants from which they suck sap through their sharp beaks. The young bugs begin feeding very early in the growing season and cause surprising losses in yield.

Several of the new insecticides have been effective against these insects, one of the best being lindane at one-fourth pound per acre in a water emulsion or a wettable powder suspension in water. The emulsions have been successfully applied in 10 to 20 gallons of spray per acre with the low-pressure power weed sprayers now in common use. These sprayers must be cleaned very thoroughly of all weed killer with a solution of 1 gallon of ammonia in 100 gallons of water before they are used for applying insecticides. Emulsions or suspensions can also be applied in more dilute form with high-pressure sprayers such as are used for treating vegetable and fruit crops.

Good control has been obtained with a 5 percent benzene hexachloride or toxaphene dust applied by airplane or ground equipment at the rate of 20 to 30 pounds per acre. One pound of methoxychlor per acre in a spray suspension or emulsion was also effective, even when applied in as little as 5 gallons of spray per acre.

For best protection the insecticide must be applied before the new growth is more than 8 inches high and before many of the young bugs have become enveloped in froth. It has been suggested that the second crop can be protected without causing a residue hazard by spraying or dusting the stubble as soon as the first crop can be removed from the field and before the second crop has attained much growth.

When used as recommended, methoxychlor can be safely applied to crops being grown for hay or forage, but lindane, benzene hexachloride, and toxaphene should be used only on crops being grown exclusively for seed. If applied to crops grown for hay or forage they may contaminate the meat, milk, or eggs of animals fed thereon. Benzene hexachloride or lindane should not be applied to fields that will be planted to potatoes, other root crops, or peanuts, as they may cause an off-flavor in such crops.

Although more expensive than the above-mentioned insecticides, a 0.75 percent rotenone dust at 25 to 40 pounds per acre has been recommended and can be safely used for spittlebugs on crops grown for hay, forage, or food.

THE ADULTS AND LARVAE of the clover root borer, a beetle that burrows in the roots of red clover, kill many of the plants and thus rapidly deplete stands. No satisfactory method of preventing the damage has been available. However, several research workers have succeeded in greatly reducing infestations by treating the clover with a dust containing benzene hexachloride, chlordane, aldrin, parathion, or certain other new insecticides in the fall or spring to kill the adults during their spring flight period. Some of the treatments also gave good control of spittlebug infestations. From the results to date it appears that the insecticidal control of the clover root borer will be practical, but at this writing further information is needed on possible residue hazards involved, before definite recommendations can be made.

Two SPECIES of grayish weevils only about one-tenth inch long, called clover seed weevils, attack the florets or immature seeds of alsike ladino, and red and white clover being grown for seed, and seriously reduce the yield. Most of the damage is done by the larvae working deep in the blossoms. These weevils originally came from Europe and no satisfactory method of controlling them was known until very recently. Experiments have shown that one treatment with 20 pounds of 5 percent DDT dust evenly applied by airplane or ground machine when about 20 percent of the clover heads have withered and turned brown will control them in most seasons under Oregon and northwestern Idaho conditions. To avoid killing honey bees and other pollinating insects, the dust should be applied early in the morning or late in the evening when those insects are not working on the blossoms.

Favorable experimental results have been obtained by workers in the New York Agricultural Experiment Station with a dust containing 1 percent of parathion.

A little weevil, known as the vetch bruchid, infests the seeds of the hairy, woolly podded, and smooth vetches but not those of common vetch. Because of its winter hardiness, hairy vetch is a valuable winter cover crop in the South. This weevil, which undoubtedly came into this country in seed imported from Europe, ruined the production of hairy vetch seed in the Eastern States. Before DDT came along it had also nearly ruined the production of this seed in Oregon and southern Washington, the only area from which it could be obtained in quantity during and after the Second World War. In tests of various insecticides it was shown that good seed crops can be obtained if hairy vetch is treated by airplane or ground machine with a 3 percent DDT dust at the rate of 25 pounds per acre as soon as the first pods appear outside the fading hairy vetch flowers. The general use of this method of control has enabled Oregon growers to continue the production of hairy vetch seed.

THE SOUTHERN CORN ROOTWORM is the larva of the spotted cucumber beetle. It is a white worm about three-quarters inch long when full-grown, with a brown head and tail-plate. The worms live in the soil and attack the underground parts of many kinds of plants, including corn and peanuts. Cultural methods of preventing the damage they do to those crops have never been very satisfactory, but it has been found that they and some other soil-inhabiting insects can be destroyed by treating the soil with new insecticides. Benzene hexachloride and lindane are effective against them but cannot be recommended for use as soil insecticides because they are likely to impart a disagreeable odor or flavor to the crop or to succeeding crops.

The Louisiana and South Carolina Agricultural Experiment Stations have conducted extensive tests with soil insecticides for the control of the southern corn rootworm, the sand wireworm and the seed-corn maggot as pests of corn. Following successful results with chlordane, they recommended it in 1950 for the purpose, with certain reservations, and it has been quite widely used by Louisiana and South Carolina farmers. The chlordane is applied in the drill rows at corn-planting time, at the rate of 1 to 2 pounds per acre, either mixed thoroughly with the fertilizer, with old sawdust, or with sand. One of the reservations is that chlordane should never be mixed with fertilizer containing lime or any other alkaline material. More information is needed on the possibility of injury of one kind or another, such as adverse effect on flavor, from the use of chlordane or other organic insecticides on food and feed crops. Attention is also called to the precaution that if fertilizer is to be the carrier of the chlordane or other organic insecticide the mixture should be used within 2 or 3 weeks after processing. There is a possibility that deterioration of the insecticide may result from longer storage.

A single application to the soil surface of 2 pounds of aldrin or 25 pounds of toxaphene per acre is recommended for control of the southern corn root-worm on peanuts. Aldrin is applied as a 2.5- or 5-percent dust and toxaphene as a 10 or 20-percent free-flowing mixture.

VARIOUS SPECIES OF WIREWORMS are pests of cereal and forage crops in different parts of the country. These are small, yellowish or brown worms about 1 inch long and are immature stages of click beetles. They live in the soil and injure plants much as the southern corn rootworm does. As I mentioned in the discussion of that insect, it is known that material damage to corn by certain species of wireworms can be prevented by the use of chlordane as a soil insecticide.

British and Canadian workers have reported good protection of small grains and corn from wireworms by treating the seed uniformly and thoroughly with a dust containing from 20 to 40 percent of purified gamma benzene hexachloride (BHC). This can also be combined with a fungicidal dust for protection of the grains from certain fungus diseases as well as wire-worms. Only dusts containing purified gamma BHC should be used because the crude BHC is harmful to germination. Depending on the quantity of seed to be sown per acre, enough of the dilute dust is applied to the seed to provide 1 ounce of actual BHC per acre. Not more than 1 ounce of this ingredient should be used per bushel of seed. The seeding rate of grain should be reduced about one-fourth in fields where, in the past, a heavier than normal rate has been used to overcome the effects of crop thinning by wire-worms. Otherwise the stand may be too heavy for best yields, especially in dry years. The seed grain should not be treated more than a week or two in advance of seeding, or germination may be lowered. Planting of treated seed in dry soil should be avoided.