Reticulitermes flavipes, a termite.

Millipedes, pillbugs, slugs, and snails are often troublesome to flowers and shrubs located in damp and shaded places where decaying vegetation is abundant. Millipedes often attack sprouting seeds or roots and bulbs. Pill-bugs, sowbugs, feed on the tender roots and shoots. Slugs and snails feed on the leaves, stems, or roots of plants.

Treatment: Poisoned baits have been used extensively, but they are being replaced largely by the chlorinated compounds. For millipedes and pillbugs use DDT, toxaphene, or chlordane. For slugs and snails, baits containing calcium arsenate plus metaldehyde are most effective, especially with high temperature and low humidity. These recommendations apply outdoors and in greenhouses.

The black vine weevil is typical of snout beetles that attack stems and roots. The needles of yew, especially on the innermost branches, are bitten off at the tip along one side or eaten completely by the adults. They also feed on the bark of the stems and branches above ground. The young, white, grublike larvae feed on the rootlets, and later girdle or strip the bark from the larger roots. Arborvitae, astilbe, maiden-hair fern, gloxinia, hemlock, primrose, rhododendron, tuberous-rooted begonia, and wisteria are among the more than 75 greenhouse and outdoor plants this pest attacks. Outdoors, the insect usually breeds on strawberry, yew, rhododendron, or on such weeds as dandelion or broadleaf plantain. The adult is black with patches of yellowish hair scattered over its roughened body and is about two-fifths inch long. The winter is passed -mostly as nearly full-grown larvae or as pupae. The wingless adult females emerge in June and July. There is one generation a year.

Treatment: Spray the above-ground parts of the plants with arsenate of lead, DDT, chlordane, or BHC in the form of emulsions or wettable powders late in June or early in July to kill the adults. This will prevent feeding on the bark and oviposition. Poison baits containing calcium arsenate, bran, and molasses are also useful. To control the ground-inhabiting grubs, the sprays or powders made of DDT or chlordane must be mixed with the soil.

Additional information on the biology and control of the insects mentioned in this article will be found in the publications cited, as well as in articles published on the subject by the various universities and agricultural experiment stations throughout the country.

THE INSECTS we have mentioned here are examples of a large number that infest flowers and shrubs. The measures we recommend against a specific insect often are effective against others of the same group. That they be controlled is of growing importance,

just as the plants they infest are of increasing importance to home owners, gardeners, commercial florists, and nurserymen throughout the United States.

C. A. WEIGEL is a senior entomologist in charge of the Beltsville laboratory of the division of truck crop and garden insect investigations, Bureau of Entomology and Plant Quarantine.

He joined the Department in 1918 and has been associated with studies on insect problems of greenhouse and ornamental plants for more than 30 years. Dr. Weigel, a native of Massachusetts,

is a graduate of the University of New Hampshire and holds advanced degrees from Ohio State University.

R. A. ST. GEORGE is an entomologist in the Bureau of Entomology and Plant Quarantine and is stationed at the Agricultural Research Center at Beltsville. He is a graduate of the University of Massachusetts and George Washington University. He has been associated with the division of forest insect investigations since 1918 and has specialized in research problems concerning insects that affect forest and shade trees and ornamental shrubs.

Slug.

Sowbug, or pillbug.

Millipede.