How do I get rid of whiteflies in my greenhouse? Many a grower has pondered this question when these nasty pests wreak havoc on their greenhouse crops.
Understanding how to get rid of whiteflies starts with recognizing the damage they cause on floral and vegetable crops. Their sap-sucking tendency reduces plant vigor, leading to stunted growth, yellowing of foliage, and premature leaf drop.
While feeding, whiteflies leave behind a sticky, sugary goo known as honeydew. The black sooty mold that colonizes the honeydew detracts from the plant’s visual appeal and market value.
Whiteflies also cause damage and death in greenhouse crops by transmitting plant diseases.
Many growers turn to Integrated Pest Management (IPM) as a way to get rid of whiteflies. IPM uses a mix of cultural, physical, biological, and chemical strategies to keep greenhouse pests in check while limiting heavy pesticide use.
Whitefly Species You’ll Likely See in the Greenhouse
Despite their name, you won’t find whiteflies in the fly family. They’re soft-bodied, winged insects more closely related to aphids and scale insects. They belong to the Aleyrodidae family and get their nickname from their white wing color.
Two species spotted commonly in greenhouses include the greenhouse whitefly (Trialeurodes vaporariorum) and the sweet potato whitefly B-biotype (Bemisia tabaci).
The Q-biotype of (B. tabaci), also known as the MED whitefly has also become a highly problematic strain of the sweet potato whitefly with stubborn pesticide resistance.
Check out the comparison below for some distinguishing characteristics between greenhouse whiteflies and sweet potato flies.
| Greenhouse Whiteflies (T. vaporariorum) | Sweet Potato Whiteflies B-biotype (B. tabaci) | |
| Wings | Hold wings flat, laying horizontally over their back when at rest | Hold wings tent-like over body at slight angles—similar to a pitched roof; wings don’t fully cover body, the abdomen peeks through |
| Body | Light yellow | Light yellow |
| Eggs | Females lay pale-yellow turning to purplish-gray eggs on undersides of leaves | Lay white turning to dark brown eggs in groups; eggs have short stalks on broad end |
| Damage | Suck sap out of plant leaves, excrete sticky honeydew, transmit viruses | Suck sap out of leaves, seedling death, reduced plant vigor, streaking on leaves, transmit viruses |
The adult lifespan for whiteflies lasts anywhere from 30 to 40 days. Females lay hundreds of eggs on the undersides of leaves during their short lives.
How to Get Rid of Whiteflies
Start With Prevention
Prevention is the first line of defense against whiteflies.
Keep up with greenhouse sanitation and destroy virus-infected plants or those with heavy pest infestations. Maintain a weed-free greenhouse inside at all times and control weeds outside that could harbor whiteflies.
Check your incoming plant and cutting shipments for pest insects and quarantine them before moving them into the main greenhouse. Scout your crops regularly.
Try Companion Planting
Growers use companion planting to help control whiteflies. This is a method of growing certain plants close together so one helps protect or support the other.
For example, whiteflies dislike marigolds and zinnias. When planted nearby, they can help drive whiteflies away from other commercial crops.
The papaya banker plant system uses papaya plants to raise a different kind of whitefly—the papaya whitefly (Trialeurodes variabilis)—that only feeds on papaya and doesn’t harm crops. These whiteflies help support beneficial insects like tiny parasitic wasps (Encarsia sophia) and predatory beetles (Delphastus catalinae and D. pallidus), which then go on to attack pest B. tabaci whiteflies in greenhouse vegetables and flowers.
This setup is different because the harmless papaya whiteflies don’t fight pests directly. Instead, they feed beneficial bugs—like parasitic wasps and beetles—that move off the banker plant and go after the harmful whiteflies.
For more information, see Whitefly Management Using Banker Plant Systems.
Put Biological Controls to Work
A common question when it comes to how to get rid of whiteflies is what beneficial insects can be used to control them.
One of the most famous predators of whiteflies is the ladybug. It likes nothing more than making a meal of whiteflies, aphids, mites, and other harmful pests.
Biologicals such as Encarsia formosa and Eretmocerous californicus have proven effective for the greenhouse whitefly. Eretmocerus species host-feed and parasitize sweet potato whiteflies, causing death. Chrysoperla species larvae (lacewings) also prey on whiteflies.
White- and yellow-colored sticky traps attract adult whiteflies when placed near vulnerable plants or spaced along benches. You can also use traps to monitor pest populations.
Sweet potato whiteflies tend to avoid greenhouses covered with UV-absorbing greenhouse plastic films.
Apply Organic Sprays
There are also some organic solutions you can mix with water and spray on your plants to discourage whiteflies.
- Insecticidal Soaps: Insecticidal soaps disrupt the insect’s cellular membranes and eliminate the protective waxes and secretions that coat the pests, which results in dehydration and death.
- Neem Oil: Neem oil is an organic pesticide created from the seeds of neem trees. But, be warned, it has a unpleasant smell.
- Spinosad: Spinosad is an organic insecticide made with a soil bacterium. It is typically toxic to many insects but does not harm most plants.
- Essentria IC3: Essentria IC3 is a safe pest control solution made with rosemary oil, geraniol, and peppermint oil.
Use Pesticides Sparingly
Unfortunately, whiteflies have developed resistance to several insecticides, so rotate insecticides with different modes of action (MOA) when trying to get rid of whiteflies. With a little research, you can find some good foliar and systemic insecticides. You can also use insect growth regulators.
Control the Environment
Whiteflies love warm, humid climates—just like the subtropics. If your greenhouse gets too hot or overly humid, they’ll thrive and multiply fast. Decreasing your humidity levels and avoiding high temperatures can help decrease whitefly populations.
A good environmental controller does a great job of maintaining a greenhouse environment that’s healthy for plants, not pests.
Also, over-fertilizing your crops, as whiteflies enjoy feasting on plants with excessive foliage growth and yellowing leaves.
Strengthen Your Greenhouse Set-up
Pest control measures involving the greenhouse structure itself aren’t mentioned as often, but they’re still an important part of IPM to get rid of whiteflies. That’s because the structure itself is one of the biggest barriers standing between your plants and harmful pests.
Taking these actions goes a long way toward helping you get ahead of whiteflies:
- Create a designated quarantine spot away from other plants
- Install insect screening on your intake and exhaust vents
- Add a buffer-zone or air-lock entry before entering the main greenhouse
- Prevent overwatering and overfertilization with the right irrigation system
- Seal up gaps and cracks in the greenhouse
Our team can help you design a greenhouse setup that acts as a barrier to keep pests out and your crops protected. Contact us to get started.
Good Whitefly Control Takes Time and Dedication
Dealing with pests in the greenhouse is inevitable to a certain extent. IPM may seem like a lot, but with the right info and a plan in place, you’ll give your crops the best shot at staying healthy and pest-free.
