DDT (dichloro-diphenyl-trichlorethane). A chlorinated hydrocarbon, the first organic insecticide to sweep the country. As both stomach and contact poison it gives excellent control of boxwood and holly leaf miners, iris, lilac, peachtree, and other borers, bark beetle vectors of Dutch elm disease, sawflies, cankerworms, gypsy moth and many other caterpillars, codling moth, gladiolus thrips, Japanese beetles as adults or grubs in soil, and leafhoppers. It does not control Mexican bean beetles and bagworms.

On the debit side DDT vastly increases the incidence of mites-red spiders, spruce mite, red mites, etc.-through killing their parasites and to a lesser extent encourages many aphids, some scale insects. It injures most cucurbits rather severely, sometimes tomatoes, and some varieties of camellias. It has a long residual effect and if used continuously may build up in the soil to injurious proportions. Used in the garden near pools it may kill fish. In large-scale operations it has reduced bird pop ulations, but when used at minimum dosage for control and outside the nesting season it is not very dangerous.

DERRIS. A tropical plant, source of rotenone.

DIELDRIN (a derivative of aldrin). First released for control of cotton pests but coming into much wider usage for wireworms and many other soil insects, thrips, Argentine and harvester ants, etc. Used as a foliage spray for leaf miners it has chematherapeutic value, killing the young miners inside the leaves. It is a strong poison; wear gloves when handling plant parts that have been recently sprayed or dusted.

Dilan (nitroparaffins, Commercial Solvents Corp., 17 E. 42nd St., New York 17, N.Y.). Particularly effective for Mexican bean beetle, promising for armyworms, plum curculio, oriental fruit moth.

Dimite, IMC (Di (p-chlorophenyl) methyl carbonol, Sherwin-Williams, 101 Prospect Ave., N.W., Cleveland 1, Ohio). A miticide especially recommended for cyclamen mite. Use 1 teaspoon per gallon of water.

DINITRO COMPOUNDS. Derivatives of cresol and phenol used in some dor mant sprays, chiefly to kill aphid eggs, sometimes in dilute dust form for mites in growing season. Sold as DN dusts or sprays or Elgetol.

Dithane D-14 (disodium ethylene bisdithiocarbamate, Rohm & Haas Co., 222 W. Washington Square, Philadelphia 5, Pa.). Outstanding in control of tomato and potato blights, onion blast and mildew, azalea flower blight, Botrytis blight and Stemphylium leaf spot of gladiolus. For tomatoes it is used at rate of 2 quarts D-14, 1 pound 36% zinc sulfate, and 1/2 pound lime to 100 gallons of water; on flowers, 1 quart D-14, 1 pound 25% zinc sulfate, 1/2 pound lime, and I ounce B 1956 spreader.

In small quantities the latter is 2% teaspoons D-14, 1 teaspoon each of zinc and lime, 5 drops B 1956 or 1/3 teaspoon Dreft per gallon. The zinc sulfate is vitally necessary in the mixture to prevent injury; lime may possibly be omitted.