Types of Garden Enemies
IMPORTED CABBAGEWORM (Pieris rapae).
Large, irregular holes in cabbage leaves, also broccoli and other crucifers, lettuce, nasturtium, sweet alyssum, and mignonette are eaten by velvety green worms. They have a faint orange stripe down the back, are about 1 1/4 inches long, and drop masses of green or brown pellets. The adult is our familiar white cabbage butterfly which emerges from a chrysalid hung on a plant or building near the vegetable garden. There are 3 to 6 generations. Another green caterpillar, the cabbage looper, has thin white stripes along the abdomen and the same looping habit as cankerworms.

Control. Spray or dust widi DDT before edible plant parts are formed, then with rotenone.

LEAF ROLLERS or LEAF TIERS
are caterpillars which feed protected by the rolled up leaf of the host plant. Some species act also as budworms. The red-banded leaf roller in orchards has been increased by the use of DDT but can be controlled by lead arsenate. For other species, such as canna leaf rollers, DDT can be used.

TOMATO HORNWORM (Protoparce quinquemaculatd) and TOBACCO HORNWORM (P. sextd).
Both of these very large, 3 to 4 inches long, worms are green with a slender horn protecting from the rear. This horn is black in the tomato worm, which has 8 diagonal white stripes along the body (Figure 23). The tobacco worm has a red horn and only 7 white stripes. Both species feed on tomato, tobacco, eggplant, pepper, potato, and petunia, and one or two worms can defoliate a plant in short order. In the South there may be two generations, but in the North there is but one, hibernation being as a pupa in soil. The adults are the large hawk or humming bird moths that fly around at dusk sipping nectar. They are gray or brown with white and dark mottlings, orange-yellow spots on the abdomen, and a wingspread of 4 or 5 inches.

Control. Dust plants with 5% DDD or 10% toxaphene or with calcium arsenate. Natural enemies keep hornworms in bounds, including a braconid wasp that covers the caterpillars with white cocoons that look like eggs. Do not destroy such hornworms; let the parasites escape to keep up the good work.

CHLOROSIS
Yellowing of foliage, loss of normal green color, is called chlorosis. It may be due to a virus, as in aster yellows, or to a deficiency of nitrogen or other nutrient, or to lack of oxygen in a water-logged soil, but most frequently it is due to unavailability of iron in a too-alkaline soil. Broad- leaved evergreens which prefer an acid soil are frequently affected, but in regions where the soil is normally alkaline all plants may become somewhat chlorotic.




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