How to get rid of whiteflies on tomatoes in a greenhouse

Growing tomatoes in a greenhouse is much more profitable than in open beds. The harvest can be obtained much earlier, and the fruiting period is significantly extended. And if the building is heated, you can provide your family with their favorite fruits year-round.

But greenhouse growing has its drawbacks. The most important is the microclimate, which is favored not only by tomatoes but also by pests. One of the most dangerous is the whitefly, which can destroy an entire crop in no time.

Characteristics of the pest

The whitefly got its common name from its appearance. The butterfly closely resembles a moth, but is smaller and has snow-white, elongated wings. The scientific name for this pest, which belongs to the small, homoptera-like flying insects, is Aleurodida. The butterfly's body is small, about 2 mm.

There are over 300 species of this butterfly in the wild. They live worldwide in moderately humid and warm climates.

Only a few species of this voracious pest are found in our country, and all of them are very dangerous to tomatoes. However, the butterflies attack not only tomatoes but also other plants growing nearby.

Life cycle of whitefly

For whiteflies to appear in a greenhouse, at least one adult female must be present. The butterfly settles on the underside of a leaf and begins laying eggs. These are oblong and white. In just a week, a single "mother" will produce over 200 "babies."

The eggs are hard to spot. If the butterfly is only 2 mm long, that's how tiny its eggs are! But if you really want to, you can still spot them. After all, 200 eggs isn't five or ten.

In comfortable conditions, a larva will hatch from the egg within a week. This tiny worm moves about in search of the most suitable "home." Once it finds one, the insect stops moving, stands still, and begins actively feeding, literally growing "before our eyes."

After two weeks, the worm's yellowish, translucent body will be covered with a white coating. This coating is very dense and waxy. It serves primarily a protective function.

The next phase begins, and the whitefly transforms into a pupa. At this point, the insect is immune to any control measures a gardener might employ, so there's no need to waste effort. This period lasts approximately 14-16 days, after which the whitefly emerges as an adult.

This is almost an adult; in just a few days, it will be able to fly from place to place and produce offspring. However, as long as there's space left on the bush and enough sap to feed, there's no point in the insects searching for a new one.

A whitefly living in a heifer is capable of laying eggs 15 times per season.

Signs of appearance

Detecting the presence of whiteflies is quite difficult. However, it is quite possible, even during the very first stages of egg laying. Regular inspection of the plantings is all that's needed, paying particular attention to the undersides of tomato leaves.

A greenhouse, hothouse, greenhouse, and other spaces with a warm, humid microclimate are ideal for insect development. And succulent leaves and plant stems are the best delicacy for them.

You can only tell if your plantings are under attack by pests visually. But that's only at the very beginning. If entire "families" are involved, simply touching the bush will cause a white "cloud" to rise. A flock of butterflies will fly up. It will be impossible to miss them.

Symptoms of damage

The following symptoms of butterfly infestation should cause alarm in gardeners:

• the color of the plant becomes cloudy, they become sticky, and acquire a “varnished” coating;
• mold-like spots appear on the leaves;
• young leaves begin to curl and wither; in advanced stages, the same signs appear on older leaves;
• a yellowish “mosaic” appears on the leaf blade;
• the fruits rot, dry out and die;
• fungal diseases begin.

The more advanced the infestation, the more difficult it is to control whiteflies. Only timely measures can protect crops from complete destruction.

Damage from whitefly

The pest butterfly is very dangerous. It feeds on plant sap, absorbing large quantities. Each meal leaves punctures on the surface through which infection can enter. These wounds also prevent photosynthesis from occurring normally.

With a small insect population on tomatoes, their growth slows. If left untreated, the plant will dry out, wilt, and eventually die completely.

As a result of its vital activity, the whitefly secretes a cloudy, sticky liquid that covers the affected plant and creates an ideal environment for the development of various pathogenic bacteria.

Pest control methods

It's easier to prevent any problem than to deal with it later. Therefore, preventative measures against whitefly infestations should be included in every greenhouse owner's mandatory checklist.

All methods of insect control can be divided into:

• mechanical;
• chemical;
• biological;
• folk.

Mechanical methods

Whiteflies are very tenacious and not easy to control. However, they are very sensitive to frost. Therefore, in late fall after harvesting and in early spring before gardening, it's essential to open the windows and doors of the greenhouse (and if possible, remove the cover completely) and thoroughly freeze them.

Many gardeners sprinkle a layer of snow on the soil in their greenhouse. This produces excellent results. Besides freezing the soil and killing overwintering larvae, the snow provides the beds with essential nutrients as it melts.

In the fall, it is essential to thoroughly remove plant debris, wash the greenhouse structure with disinfectants, and seal any cracks.

If the area is already infected, the soil should be watered with a solution of copper sulfate and bleach. Specialty store employees or experienced farmers can help you determine the proper proportions. The composition of the solution and its strength depend on the soil composition. Sometimes, simply deep digging and adding a small amount of lime to the beds is sufficient.

Chemical treatment

If whitefly infestations fail to be prevented, chemical treatment will be necessary. While safer methods are certainly possible, only chemical treatments currently offer effective results.

Insecticides must be diluted according to the instructions on the packaging and safety precautions must be observed during work (use protective clothing, respirators and gloves).

The following preparations are the most effective in the fight against whiteflies:

• Confidor. A single treatment per season is sufficient. Recommended for use in spring, two weeks before planting. However, it can also be applied at any stage of the growing season.
• Fufanol or Mospilan. These solutions are also intended for single-use treatment;
• Verticillin or Pegasus. Can be used both for prevention, applied in early spring, and for treatment in the middle of the growing season;
• Actellic is a universal product. It can be used to control whiteflies at any stage of their development.

Biological method

The use of biological methods for controlling the butterfly pest is surprising to many because of its unusual nature. At a specialty store, you need to purchase a bottle or disposable tube (depending on the size of your greenhouse) containing beneficial parasites called encarsia.

In the greenhouse, open the container and distribute its contents evenly. Within ten days, the tiny insects will find the whitefly larvae and lay an egg (or, in rare cases, two) in each. Within a few days, the infected larvae will become mummified.

Encarsia is bred in special laboratories to primarily protect greenhouse tomatoes and cucumbers from the pest butterfly.

Folk remedies

For small greenhouses and hotbeds, as well as for preventative purposes, you can also use folk remedies to control whiteflies. The butterflies dislike the smell of dill and ghoul, so these plants can be planted along the beds. You can also regularly spray the plantings and the greenhouse itself with infusions of garlic, tobacco, or onion peels.

One radical method is to light smoke bombs. To do this, install a metal stand in the greenhouse, place the smoke bomb on it, light it, and quickly exit, tightly closing all windows and doors. It's best to avoid entering the greenhouse for 3-5 days, and then thoroughly ventilate it.

Sticky traps also work well. Place them around the perimeter of the greenhouse. Their scent and color will attract the butterfly.

Whitefly prevention

Preventative maintenance to protect your plantings should be carried out regularly. This primarily involves regular inspection of the plants. By examining every 5-7 bushes, you can determine whether there is any damage. This should be done at least once a week, and if the greenhouse windows and doors are opened frequently, every other day.

Butterfly larvae can end up in garden beds with infected seedlings or untreated tools and work clothes. To prevent this, it's best to treat young seedlings with a deep pink solution of potassium permanganate before planting. You can also water the holes with this solution. It's recommended to use separate tools for the greenhouse and treat them regularly.

One way to prevent infestation is to maintain proper planting practices. The denser the plants are, the more favorable the environment for whiteflies will be. Adequate ventilation is also crucial. It's important to prevent stagnant air.

Autumn cleaning of the greenhouse

After the harvest season, the greenhouse should be thoroughly cleaned. If the structure is collapsible, simply wash it thoroughly and treat it with disinfectants (household chemicals can also be used, but keep it away from the garden beds). The beds themselves should be dug over and treated with a solution of potassium permanganate or watered with very hot water.

With permanent structures, there's more work involved. The greenhouse needs to be cleaned not only inside but also outside. It's essential to inspect it for cracks and damage.

All plant debris must be removed from the beds, the top layer of soil must be removed by at least 7 cm, replaced with new soil, and treated with disinfectants.

Sulfur candles work well. They can get rid of not only whiteflies and other insect pests, but also fungi and infections. Place the candle on a metal base in the center of the greenhouse and set it on fire, quickly leaving the greenhouse. After two or three days, ventilate the area well.

If the structure is metal, it would be a good idea to treat it with an anti-rust agent, and it would be better to whitewash or varnish the wood.

At the very end of the work, the soil cleared of plant remains must be watered with a solution of copper sulfate (250 grams per bucket of water.)

There's no need to worry about a whitefly infestation. Simply carry out preventative measures promptly and consult with professionals if an infestation does occur.