Types of Garden Enemies
Control. Spray with DDT to control vectors when leaves are fully open and repeat 1 or 2 months later. European and Asiatic elms are resistant.

This has become a major threat to peach production; it spreads to peaches from choke cherries around the orchard, al- though the vector is not yet known. Diseased trees are lighter green with red and yellow spots on leaf blades, the discolored areas often falling out; young trees die; fruit shrivels and drops or ripens with a bitter taste. Choke cherries should be eliminated. Chemotherapy, treating the soil with chemicals to arrest the disease, has been effective in experimental work.

Another western disease, of tomatoes and other vegetables and of flowers, has been found in New Jersey on dahlias and tomatoes. Tomato foliage has bronze, ringlike lesions, and the fruits are marked with concentric rings of pale red, yellow, or white. Yellow ring- spots appear on dahlia leaves, reddish-brown to purple spots on sweet pea stems, and circular to oval spots on leaves. Calla lilies have spots and streaks that are first white, then brown. Onion thrips and flower thrips are the insect vectors, but they are hard to control. Rogue out diseased specimens and keep down weeds.

This is the reason why you should not smoke when you garden or work in the greenhouse. Incredible as it seems, the virus lives through the curing of tobacco for cigars and cigarettes and you can infect seedlings of tomato, pepper, eggplant, petunia, and other solanaceous plants just by handling them after touching tobacco. Tomatoes have a typical mottling, with curling of leaves. Lily, potato, and peach aphids transmit the virus.

Control. Don't smoke while working; wash your hands thoroughly after smoking before transplanting, pruning, or tieing up plants in the above list. Removed diseased plants immediately and scrub before touching healthy plants.

Like bees and sawflies, wasps belong to the order Hymenoptera, having their 2 pairs of wings joined together. Most wasps are garden friends. They pollenize our fruits and parasitize our insect enemies. We have braconid wasps on tomato hornworms, ichneumen wasps that kill borers in wood, Tiphia wasps for Japanese beetle grubs, etc. Sometimes this can be carried too far, for we also have hyperparasites that kill our parasite friends. Even yellow jackets who dispute the fruit we eat in the fall and send us to bed with their stings when we inadvertently disturb them are primarily useful, feeding on soft-bodied corn earworms and army- worms. There are, however, two large solitary wasps that are distinctly garden problems.

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