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How to Control Whiteflies on Tomatoes

Whiteflies are a major threat to tomato crops. They attack the leaves of tomato plants, often transmitting viruses that devastate plant production. The following is a guide on how to control whiteflies on your tomato plants.

Planting Protection

Some plants are notorious for being whitefly breeding grounds. You can minimize the chances of a whitefly infestation by keeping your tomato plants away them. Melons and cotton are the two most prolific sources of whiteflies. Make sure to keep your tomato plants at least a half a mile away from them. [Castle, ars.usda.gov]

Biological Protection

Fortunately, Mother Nature has given you a potent weapon in the fight against whitefly infestation. Many insects will attack and kill whiteflies. Ladybugs, big eyed bugs and lacewings will all attack and kill whiteflies in the larval stage. Wasps are the weapons of mass destruction in the war against whiteflies. The wasp species, encarsia formosa, is a parasitic nightmare for whiteflies. They will attach themselves to a whitefly body, feed on it, and then deposit eggs in the whitefly's body. A short time later more wasps will emerge, seeking out any whiteflies that are daring enough to show their faces. These wasps are tiny and do not sting people. [Cranshaw, .ext.colostate.edu/]

Pesticide Protection

The most widely used insecticides for whitefly control are organic. Whiteflies rapidly develop immunities to chemical pesticides. Neem oil is often used to control the spread of the insects. Insecticidal soap can also be used. You will need to completely soak your plants with the oil or soap, as only whiteflies that come into direct contact with the oil or soap will be killed. Do not try and kill whiteflies with chemical pesticides, as they will have little or no effect on the whiteflies. However, most inorganic pesticides will kill the insect predators of the whitefly, such as ladybugs and wasps. ["G7275 Managing Whiteflies on Indoor and Outdoor Plants", extension.missouri.edu]