Common tomato problems
By ROBERT N. BREWER, JR. Extension Service Agent

1. Plant Lice/Aphids: These small green, red or gray insects will suck a plant dry plus they secrete a sugary substance causing additional problems. To control aphids on tomatoes, use insecticidal soap or help reduce populations with a sharp stream of water directed at the leaves.

2. Wilts: There are three destructive wilts that affect plants in our area. They are: Fusarium Wilt is characterized by leaf yellowing that progresses upward from the base of the plant and the plants die slowly. Plants usually look fresh in early morning and decline during the day. This will continue for several days until the plants finally wilt permanently and die. Fusarium wilt is caused by a soil-borne fungus that can live in soil for many years.

Bacterial wilt is sudden; plants will not show yellowing of leaves. The stem of the plant in the center, or pith, becomes water-soaked, later turns brown and sometimes becomes hollow.

Tomato Spotted Wilt is caused by a virus that usually is spread by thrips. The foliage is severely spotted with light green mottling and small grayish brown, thin dead spots. Shoot tips may die. The spotted wilt virus can overwinter in weeds and ornamental plants.

3. Blossom-End-Rot: This symptom is caused by insufficient calcium when the fruit is forming, and is characterized by a large dry, brown to black and often depressed, leathery area at the blossom end or bottom of the tomato. Low calcium usually results from putting too much nitrogen fertilizer, rapid plant growth and drastic moisture fluctuation caused by drought, heavy rain, or improper watering. Control blossom end rot by using quick reacting lime and maintaining good moisture.

4. Tomato Hornworm- Plants may look bare and upon closer inspection you may see frass or caterpillar droppings and missing stems and leaves. An even closer look may reveal a large green worm or caterpillar which is the larvae of a Hummingbird moth. Often these are parasitized by wasps. If the hornworm has white protrusions on its back, you may pick it off the tomato plants, and allow it to remain in the garden so the wasps may hatch and parasitize other hornworms. Bacillus thuringensis -Bt is also an effective control for large hornworm populations.

5. Whiteflies: Greenhouse whitefly is another common tomato pest. The flying adult stage is familiar to most gardeners, but the pale, motionless nymphs that feed on leaf undersides are not. Nymphs and adults remove sap and reduce plant vigor. Insecticidal soaps sprayed on the underside of the leaves may help control populations. Agood way of preventing whiteflies on your tomatoes is to inspect transplants and only buy ones that are free of whiteflies.

6. Early blight is caused by the fungus Alternaria solani. Symptoms become prevalent during the hotter months. This disease produces brown to black, target-like spots on older leaves. If severe, the fungus also attacks stems and fruit. Affected leaves may turn yellow, and then drop, leaving the fruit exposed to sunburn. Sanitation is the best control. Remove all diseased plant tissue on the ground, as the fungus overwinters on leaf debris. Do not plant tomatoes in the same place next year. Space plants farther apart to improve air circulation. Avoid overhead irrigation.