Types of Garden Enemies
Fig. 50
PYRACANTHA SCAB (Fusicladium pirinutn var. pyracanthae).
This is a disfiguring disease for an ornamental. Leaves, twigs, and fruit are infected with unsightly black scabs, spoiling the appearance of the bright berries and making them drop long before their time.

Control. Puratized Agricultural Spray and Fermate seem to be more effective than bordeaux mixture.

VIOLET SCAB (Sphaceloma violae).
There is so much overgrowth of tissue this disease is called scab, but it really is a spot anthracnose (see page 23). Reddish spots with white centers grow into elongated raised scabs often with much distortion on leaves and stems of violet, viola, and pansy.

Control. Bordeaux mixture has always been recommended in the past, but it may injure pansies, and more work is needed on newer materials.

Scales are sucking insects, close relatives of mealybugs, in the orde Homoptera. Females are alone responsible for plant injury. After a brief] crawling period, a female sticks her beak into a plant cell and remair in that position the rest of her life, if she is an armored scale, covering her body with a hard shell made of cast skins and special secretions. *

Fig. 51

Unarmored or soft scales do not have such a hard covering, and some may make sluggish movements. Only the males have wings. Dormant oil sprays have been generally used for hard-shelled scales, summer oils or other contact insecticides for soft scales. DDT controls some scales and has been valuable for orchids, but it increases other scales. Parathion, despite its toxicity to humans, has been successfully used by nurserymen in the South and greenhouse operators to control scales, but one or two species are not only resistant to parathion but increased by it. Malathon may help in such instances.

BLACK SCALE (Saissetia oleae).
This is an unarmored scale, a most destructive citrus pest in California, found also on other fruits and on. oleander, pepper tree, and rose. It is not important in the Gulf States. It is hemispherical, black with white lines on the back forming an H, 1/5 inch across. Its honeydew encourages a profuse growth of sooty mold. Oil sprays were used for control until the insect developed resistance to them; DDT and parathion are current usage.

CALIFORNIA RED SCALE (Aomdiella aurantii).
This is another California pest, also found in Texas, destructive to citrus and some ornamentals. Leaves, fruit, and twigs are injured by a toxin introduced during feeding. Scales are roundish, red, small, 1/12 inch in diameter, with a slight hump in the center, and they thickly cover twigs and branches. Young are born alive. Forms have developed resistant to oil sprays or cyanide fumigation. DDT emulsion kills crawling stage but encourages citrus red mite.

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