Types of Garden Enemies
COTTONY-CUSHION SCALE (Jcerya purchast). Very common on pittosporum, found often on rose, boxwood, citrus, and many ornamentals this scale is present throughout the southern half of the country. It arrived on acacia from Australia nearly a hundred years ago. The female scale is reddish brown but at egg-laying she attaches to herself a large, white fluted cottony sac which sticks out at right angles from the twig and is very conspicuous (Figure 50C). Inside the cotton are 600 to 800 bright red eggs. Young larvae are red with black legs; winged males are very small, covered with long white filaments. A great deal of sooty mold is the usual accompaniment to cottony-cushion scales.

Control. The saga of the search for a biological enemy of this scale, which once threatened the whole citrus industry, has been told many times. Vedalia, the Australian lady beetle, was finally brought here and proved to be the first successful example of an imported predator cleaning up a dangerous insect. When DDT is used in the spray schedule, it kills Vedalia and so allows the scale to increase. Parathion gives good control; oil sprays are partially effective.

COTTONY MAPLE SCALE (Pulvinaria vitis).
A northern scale destructive to soft maple and attacking other trees and some shrubs. I find it rather often on dogwood. The female is small, brown, flat, 1/8 inch long; she winters on twigs and in spring deposits cottony masses of wax several times her own size and covering 1500 to 3000 eggs. When the eggs hatch in June and July, young scales crawl to leaves, later migrating back to twigs. Branches die if scales are abundant for 2 or more consecutive years.

Control. Dormant spraying with a miscible oil gives best results, but oils may injure soft maples. In summer, foliage can be sprayed with nicotine sulfate and soap.

ELM SCURFY SCALE (Chionaspis americana).
The female is pear-shaped, convex, dirty white or gray; eggs are purple. Young elms are most affected. Use a dormant oil spray with nicotine.

EUROPEAN ELM SCALE (Gossyparia spuria).
This armored scale is common on all elms, covering underside of limbs and branches, weakening and sometimes killing trees, and dropping honeydew on walks and benches. Females are 1/6 to 3/8 inch long, oval, plump, reddish brown surrounded by a waxy fringe; they lay eggs over a long period. Yellow crawling nymphs feed on leaves but return to bark for winter. Male scales are like red gnats, winged or wingless. When scales are numerous, leaves turn yellow and drop and the bark is black with sooty mold.

Control. Use a dormant spray, 1 gallon of miscible oil to 15 of water. A 2% summer oil or DDT emulsion or wettable powder can be used for crawling young nymphs.




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