Tomato Yellow Leaf Curl

Tomato Yellow Leaf Curl virus
Photo: University of Florida

Problem

The new growth of tomatoes infected with Tomato Yellow Leaf Curl is stunted. Leaves on affected plants are wrinkled and have a cupped appearance. Leaves may appear yellowish betweens veins. Flowers often drop before fruit sets. 

Description

TYLC is spread by the sweet potato whitefly and the biotype B whitefly. 

Information

• Tomato Yellow Leaf Curl [PD-70]
  

Carefully remove, bag and discard affected plants to prevent the spread of the disease. Do not plant other solanaceous crops (eggplant, pepper, potato) in the area as they may harbor the virus; these solanaceous crops may be infected with TYLC virus and not exhibit any symptoms. Whiteflies feeding on nearby crops or weeds can then spread the virus. Keep the area weeded.

To control whiteflies:  Wash whiteflies off the plant with a strong spray of water. When plant is dry, apply insecticidal soap or soft bodied insect spray (see below) to the undersides of the leaves. The spray must contact the nymphs and adults to be effective. You will need to repeat the application 3-4 times in order to kill all stages of the pest. Avoid broad spectrum insecticides because they will kill parasitic wasps and other natural enemies.

If the infestation is heavy, prune the plant back heavily and throw away infested foliage in sealed bags. Keep an eye on the plant for re-infestation and spray with insecticidal soap as needed.

You can try using yellow sticky cards if the infestation is light. Whiteflies are attracted to the color yellow and will stick to the card. Or try laying aluminum foil at the base of the plant which repels the pest. Use foil with caution however; on sunny days foil can reflect the sunlight and “cook” fruit on affected plants.

Ants will “farm” whiteflies, feeding off of the honeydew they excrete, so you must control the ants if you want to get rid of whiteflies.

In areas where TYLC is widespread, try covering the crops with a barrier screen.

You could plant TYLC resistant varieties of tomato, but resistant varieties can lose their protective qualities under stress and develop the symptoms of TYLC. Consult the CTAHR publication Tomato Yellow Leaf Curl [PD-70] for sources of TYLC resistant seeds.

Soft Bodied Insect Spray Recipe
(controls aphids, mealybugs, whiteflies, scales, citrus black flies)

Begin by preparing a stock solution of Soap-Oil Concentrate:

• Combine 1 Tablespoon of mild dishwashing liquid (Ivory, Joy or Dr. Bronner’s, NOT ultra formulas like Dawn) with
• 1 Cup of vegetable oil (peanut, safflower, corn, soybean, sunflower oil)

How to use the Soap-Oil Concentrate:

• Shake the solution of Soap-Oil Concentrate very well before use
• Dilute with water by mixing 1-2 teaspoons of concentrate into 1 cup of tap water.
• Spray plants thoroughly in the morning or late afternoon, especially the undersides of leaves
• Spray once a week for 2 or 3 weeks to eliminate the insects.

Kendal Lyon, Hawaii Island Master Gardeners