Types of Garden Enemies
Fig. 54
Sooty mold is a black fungus coating on the surface of leaves, stems, or fruit composed of black mycelial threads and dark spores. The mold is not a parasite; it obtains no nourishment from the plant but lives exclusively on sweet honeydew secreted by insects-aphids, scales, mealybugs, and whiteflies. The coating is often thick and rather velvety but on aging breaks up into fragments and drops off. The mold indirectly affects plant health by interfering with photosynthesis. Fruits are small, and coloring is retarded; they are subject to decay. Evergreen shrubs under tuliptrees frequently are covered with sooty mold growing in honeydew dropped from aphids and scales overhead. Cottony-cushion scale on pittosporum, mealybugs on azaleas, aphids on crapemyrtle almost always are accompanied by disfiguring black soot.

Control is directed toward the insect, not the fungus. When whiteflies on gardenia are killed with oil sprays, or parathion, the mold rolls up and gradually disappears. See Figure 64.

These small animals, sometimes called roly-polys and resembling miniature armadillos, are not insects but belong to the lobster class, Crustacea. They are gray, oval, with segmented bodies and 7 pairs of legs, up to 1/2 inch long. One species is called a pillbug because it rolls up into a pill- like ball when disturbed. The female has a central pouch in which she lays eggs, and the young remain in this for some time after hatching. Sowbugs like damp places; you will find them under wet leaves, in decaying plant material, under flower pots. They are mostly scavengers feeding on bulbs and other plant parts rotting from some other cause, but they do sometimes attack healthy roots and tender portions of stems near the ground.

Fig. 55

Control. The use of poison bait, 1 part Paris green mixed with 9 parts of sugar, has largely given way to dusting the places where sowbugs congregate with chlordane, toxaphene, 5% DDT dust, or 1% lindane dust.

Spittle insects, sometimes called froghoppers, are rather closely related to leafhoppers, which the adults resemble, but the nymphs live in a frothy mass that looks something like white of egg beaten up. As the small greenish nymph sucks plant sap, it secretes this sap mixed with waxy body chemicals and at the same time forces air into it by a kind of bellows under the abdomen operated by the tail flipping up and down. After its last molt the nymph crawls out of its protective mass of froth and changes to a small, dull-brown adult, resembling a rather short, blunt leafhopper.

PINE SPITTLEBUG {Aphrophora parallela)
is widely distributed from Maine to Arkansas on Scotch and other pines, sometimes spruce and juniper. Terminals are often killed. The STRAWBERRY SPITTLEBUG {Philaenus spumarius) is common on strawberries, occasional on raspberry and blackberry.

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