Hollyhock. Bug (Orthotylus delicatus).—A small green bug, attacking the hollyhock with great damage.
Treatment. — Kerosene emulsion. Tobacco extracts. House-plants. See Aphides, Mealy-bug, Mites, and Red-spider, pp. 301-304. Lawns. Ants (Formica sp.). — Insects burrowing in the ground, forming " ant hills."
Remedy. — A tablespoonful of bisulfid of carbon poured into holes six inches deep and a foot apart, the holes being immediately filled up. Lettuce. Aphis or Green-fly. — A plant-louse on forced lettuce. Preventive. — Tobacco-dust applied on the soil and plants as soon as the aphis makes its appearance, or even before. Renew every two or three weeks if necessary. Fumigating with tobacco is the surest remedy. See Fumigation, p. 288. Cabbage-looper (Autographa brassiae). — Larva, somewhat over an inch long, pale green, with stripes of a lighter color, feeding on leaves of many plants, as cabbage, celery, and endive.
Remedies. — Pyrethrum diluted with not more than three times its bulk of flour. Kerosene emulsion. Hot water. Melon. Melon-worm (Diaphania hyalinata). — Larva, some over an inch long, yellowish green and slightly hairy, feeding on melon-leaves, and eating holes into melons, cucumbers, and squashes ; two or more broods.
Remedies. — Hellebore. Arsenicals early in the season. Spotted Cucumber-beetle. — See under Cucumber, p. 318. Squash-vine Root-borer. — See under Squash, p. 331.
Mushroom. Mushroom-fly. — The maggot bores through the stems of the mushrooms before they are full grown.
Preventive. — Keep the beds cool so that the fly cannot develop. When the fly is present, growing mushrooms in warm weather is usually abandonded. Onion. Maggot (Pegomya cepetorum).— Much like the Cabbage Maggot, which see (p. 312).
Remedies. — Carbolic acid emulsion. Bisulfid of carbon. Thrips (Thrips tabaci).— Minute elongate yellowish insects that cause a wilting and dying of the tops.
Treatment. —Clean culture, kerosene emulsion, tobacco extracts.
Orange and Lemon. Purple Scale (Lepidosaphes beckii). — An elongate brownish purple scale resembling an oyster-shell in shape.
Treatment. — Fumigation, using heavy dosage.
Red-scale (Aspidiotus aurantii). — A nearly circular reddish or yellowish scale.
Treatment. — Fumigation. Distillate. Black-scale (Saissetia olece). — A large soft-bodied dark brown or nearly black scale.
Treatment. — Fumigation. Distillate. Mealy-bug (Pseudococcus citri).—A mealy white soft-bodied insect nearly one-fourth inch long, occurring in masses in the angles of the branches, axils of the leaves, and around the stem of the fruit.
Treatment. — Fumigation. Destruction of all rubbish under the trees. Red-spider (Tetranychus sexmaculatus). — Minute greenish yellow mites found on the leaves. See p. 304.
Treatment. — Dry sulfur, or sulfur and water used as a spray. White-fly (Aleyrodes citri and A. nubifera). — The immature stages are found on the underside of the leaves and are scale-like in form. The adults are minute white-winged flies.
Treatment. — Fumigation. Fungous diseases (p. 290), Rust-mite (Phytoptus oleivorus). — A minute mite, causing the rust on oranges and lemons.
Treatment. — Sulfur, dry or as a spray. Thrips (Euthrips citri). — A minute, active, yellow insect that scars the fruit and curls and distorts the leaves.
Treatment. — Make four applications of lime-sulfur (33° Beau-me), 1 gallon in 75 gallons of water, adding " Black-leaf 40 " tobacco extract at the rate of 1 part in 1800 parts of the dilute lime-sulfur, as follows: — First. — Just after most of the petals have fallen from the blossoms. Second. — Ten or fourteen days after the first. Third. — From three to four weeks after the second. Fourth. — In August or September, to protect later growths of foliage. (U. S. Bureau of Entomology.)