How To Identify Whiteflies And Control / Prevent Them On Tomato Plants?

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In this detailed guide, I will show you to identify and control whitefly populations on tomato plants quickly.

Shall we dig in?

What Are Whitefly And How Does It Harm Tomato Plants?

The whitefly is a tiny white delta-winged, soft-bodied insect active during the day. It is a sap feeder about 1/12 of an inch, like the aphids.

These pests will drink the juices from tomato plants and affect their foliage.

How To Confirm That Whitefly Is Troubling Your Tomato Plants?

The most apparent signs of whiteflies troubling tomato plants are yellowing and curling of the leaves. You can confirm by checking on the undersides of the leaves using a magnifying glass for tiny whiteflies in clusters. They may fly when the plants are disturbed.

If you run your finger along the leaf, you may feel the stickiness of honeydew. After severe infestation, plants may become prone to black sooty mould and exhibit stunted growth.

Check out this video on identifying whiteflies:

Natural Ways To Control Whitefly On Tomato Plants

After confirming the presence of whiteflies on tomato plants, the next step is to control them.

You can opt for natural ways to control whitefly, including hot pepper, neem oil, horticultural oil, and releasing beneficial insects.

Method 1- Use Hot Pepper Spray

Hot pepper can be used to deter whiteflies on tomato plants due to its pungency. It is considered a deterrent rather than an insecticide to kill whiteflies.

  • Prepare hot pepper spray– Soak 30 chopped peppers in warm water for a day. Strain the solution and dilute it in 10 liters of water. Add 20 drops of liquid soap. Shake well and transfer to a spray bottle.
  • Spray on the foliage– Apply on the affected foliage to kill whiteflies larvae.

Method 2- Apply Neem oil

Organic neem oil can be sprayed on tomato plants to control whiteflies by interfering with their mating and development.

  • Dilute neem oil– Purchase organic neem oil and dilute 2-5ml of neem oil in a liter of water. Shake well and pour into a spray bottle.
  • Apply on the affected foliage– Spray diluted neem oil on the affected foliage. It is preferable to apply in the evening to avoid the burning of leaves.

This video will help you understand how to use neem oil to reduce whiteflies:

Method 3- Release Beneficial / Predatory Bugs

Whiteflies have natural predators, including green lacewings, pirate bugs, big-eyed bugs, and ladybugs. They can help in controlling the whiteflies population.

  • Purchase beneficial bugs– Buy beneficial bugs that will eat whiteflies. These can be purchased online or from insectaries.
  • Release these bugs– Read these bugs according to the manufacturer’s instructions near the tomato plants. They help in controlling whiteflies.

Method 4- Apply Horticultural Oil

Horticultural oil works to control whiteflies by smothering the insects. Avoid applying when the temperatures are over 90oF or the plants are drought-stressed.

  • Make horticultural oil spray– Mix 1.5 to 4 tablespoons of horticultural oil in a gallon of water. Shake it well.
  • Apply on the plants– Spray once or twice every week on the infested plants depending on the degree of infestation.

Physical Ways To Control Whitefly On Tomato Plants

A simple way to get rid of whiteflies is by washing the insects from the infested tomato plants with a forceful jet of water. You may also place yellow sticky traps or use a handheld vacuum to control whitefly populations.

Method 1- Place Yellow Sticky Traps

Whiteflies are attracted to the yellow colour and will flock to the cards. It can be an effective way to control the population early in the season.

  • Place yellow sticky traps- Hang yellow sticky traps near tomato plants. It is recommended to place one trap per 5 plants. You can also make one by applying a concoction of petroleum jelly with a little dishwashing liquid on yellow cardboard.
  • Collect the whiteflies- Whiteflies get stuck in the traps and will be killed.

Check out this video to know how to place a yellow sticky trap:

Method 2- Wash The Whiteflies Away

Whiteflies can be knocked off the plants using a strong blast of water using a hose. It also reduces the dusty and dry conditions that favor whiteflies.

  • Wash the whiteflies away– Wash the foliage with a forceful jet of water using the watering hose. This will dislodge the whiteflies away from the leaves and eventually die.

Take care to spray on the undersides of the leaves where the whiteflies congregate.

The video on Method 1 above also details on how to use this method effectively.

Method 3- Use A Handheld Vacuum

A handheld vacuum can be used to suck up the whiteflies. Take care to avoid sucking the leaves from your tomato plants.

  • Use a handheld vacuum– Check for whiteflies on the tomato leaves. You may use a handheld vacuum in a bad outbreak. It can help in sucking clouds of whiteflies from the infested leaves.
  • Repeat the process– You may repeat the process depending on the severity of the infestation to control the outbreak.

Chemical Ways To Control Whitefly On Tomato Plants

The different chemical ways, including insecticidal soap and imidacloprid, can be used to control whiteflies on tomato plants. Use chemical insecticides as a last choice as they may kill the beneficial insects. Also, whiteflies quickly build resistance to them.

Method 1- Use Insecticidal Soap Spray

Insecticidal soap can be used to control the whitefly population of tomato plants. Use the sprays when the plants are not drought-stressed, and repeated applications may be necessary.

  • Prepare soap spray– Mix three tablespoons of insecticidal soap in a liter of water. Shake well and transfer to a spray bottle.
  • Spray on the affected foliage– Check for the affected foliage and spray them with soap to kill any larvae or adults. Take care to cover the undersides of the leaves too.

Check out this video on controlling whiteflies using liquid soap:

Method 2- Apply Imidacloprid

Imidacloprid can be used to control whitefly nymphs. Avoid using them on flowering tomato plants. Also, it may affect honey bees and other pollinators.

  • Prepare the imidacloprid solution– Read the manufacturer’s instructions and prepare the solution.
  • Apply on the soil– Apply on the soil around the tomato plants to control whitefly nymphs.

How To Prevent Whitefly In Tomato Plants?

The best strategy to prevent whitefly from attacking tomato plants is by removing infested garden debris, conserving natural predators, and planting repellant crops. You may also use reflective mulches to monitor and reduce these pests.

Remove Garden Debris

After harvesting the tomatoes, remove and destroy the whitefly-infested tomato plants. Also, keep the weeds away from the soil. Also, reduce dust and ants that protect the whiteflies from their natural predators.

Conserve Natural Predators

You may conserve natural predators of whiteflies, including wasps and ladybirds. Practice mulching or leave a natural hedge of flowering plants to attract these predators.

You may use white or black plastic mulch about 10-20 days after transplanting. It helps in attracting and killing whiteflies.

Plant Repellant Crops

Plant certain repellant crops, including coriander or Mexican marigold to repel the whiteflies. It is preferable to plant these crops after 3-4 rows of tomatoes.

Use Reflective Surfaces

Use reflective surfaces, including foil or CDs, around the base of tomato plants. It will repel the whiteflies and keep them away from the tomato plants.

You may also apply the plastic mulch with silver paint.

What Causes Whitefly Attacks In Tomato Plants?

Whiteflies are common in greenhouse environments as they can not survive winter outdoors. They attack tomato plants when it gets warm and humid. The drought-stressed tomato plants are more prone to whitefly attacks.

Also, they are capable of overwintering and may hide in weeds. So, weeds in the soil may cause whitefly to chew on tomato plants.

Frequently Asked Questions

How to deal with black mold due to whiteflies?

Whitefly infestation may result in fungal infection and black mold on the leaves. Wipe the mold with damp towels. Spray the plant with neem oil to prevent further mold growth.

Do ants eat whiteflies?

No, ants do not eat whiteflies. They are attracted to the honeydew secreted by whiteflies. So, they farm the whiteflies and protect them from their natural predators.

Can marigolds prevent whitefly infestations in tomato plants?

Yes, marigold has been used for years to prevent whitefly infestations. These flowering plants release limonene that could reduce the presence of pests. It is suggested to use this plant as a border crop or interspersed within a tomato field.


I hope this guide has provided various measures to control and prevent whiteflies in your tomato plants. You may follow the steps to keep these pests under control.

Please share your experiences in dealing with these pests.

Also, do pass on your guide to your gardening friends to help them!