Whitefly in a greenhouse on cucumbers: how to get rid of white midges and insects in the garden

What kind of pest is this

Whitefly, or white midge, is a dangerous pest . The insect feeds on plant sap and reproduces very quickly. The whitefly and its larvae usually settle on the lower surface of the leaf.

Often the insect appears in greenhouses, as it loves a warm and humid climate. Lives on plants in groups.

Appearance

Whiteflies (pictured) are small moth-like insects with milky white wings and a white or yellow body. They reach no more than 3 mm in length. They have 4 wings, covered with a white coating reminiscent of flour.

Whitefly larvae are small, up to 0.3 mm in size. They look like translucent yellow scales. Having hatched from the egg, they attach themselves to the leaf and begin to actively feed on its juice.

Later comes the pupal stage. At this time, the larva is maximally resistant to various drugs. Then an adult with wings emerges from the pupa, which is capable of flying to other plants and reproducing.

Symptoms of cucumber damage

Due to the fact that whiteflies live on the underside of leaves, they may not be noticed immediately. It is necessary to systematically inspect cucumbers and know the signs by which whitefly infestation is determined:

the surface of the stems and leaves becomes sticky and covered with a white coating;
the leaves curl, fade, wither;
yellow or green spots with blurred boundaries appear on the leaves;
larvae are visible on the inside of the leaf;
over time, a black coating appears - sooty fungus (such an infected plant is dug up and burned);
The development of the vegetable slows down noticeably and the yield decreases;
if you shake cucumbers, a swarm of white midges rises into the air - these are whiteflies.

If at least one of the listed signs is detected, it is necessary to urgently take measures to combat the pest.

Signs of infection of cucumber bushes

In order not to miss the moment of parasite infestation, you need to regularly inspect cucumber bushes growing in the greenhouse and outside. The first sign of a problem will be the presence of small gray insects. These are midge larvae that usually collect on the underside of leaves.

Adults are small white butterflies. If there are only a few of them yet, you can try to collect insects by hand. The butterflies lay a large number of transparent eggs, from which new midges hatch in just a few days. As they grow, they feed more and more intensively, drawing out the last strength from the vegetable crop. And then they stop eating, having reached the pupal stage. Carefully inspect the leaves. First, white dots and spots appear on them. Gradually the tops turn yellow and finally wither.

Damage caused

Since the insect feeds on plant juices, affected cucumbers begin to lag behind healthy ones in development . Their leaves dry out and fall off over time, and subsequently the entire crop withers.

Due to lack of fluid, the ovaries cannot fill and fully ripen. This leads to a sharp decrease in yield.

The white midge carries diseases such as jaundice, yellow mosaic, chlorosis, leaf curl and fruit necrosis. In places where the whitefly drank the juice and left its excess, chlorophyll is not formed and various pathogenic microorganisms develop.

What is the danger of whitefly

The reason for the death of plants is the exceptional gluttony of the parasitic butterfly; its “appetite” significantly exceeds the need for nutrition. Subsequently, it begins to secrete “dew,” a kind of secretion that, settling on the leaves of tomato and cucumber, forms a sooty coating (fungus).

It blocks the pores of plants, preventing air exchange and photosynthesis. A black, sticky crust appears on the leaves, then they die.

Additionally, the whitefly spreads a lot of diseases, so the fight against it is long-term, complex, using various pesticides.

How to deal with whitefly on cucumbers in a greenhouse

As soon as you notice the first signs of pests appearing in the greenhouse, immediately take measures to destroy them . First, try mechanical methods of removing whiteflies from a bush:

Collect the insect by hand with a sponge dipped in soapy water.
Remove and burn the leaves on which the larvae have settled. It makes sense to remove leaves if the plant is slightly damaged. If the whitefly has occupied more than 40% of the cucumbers, this method will not work.
Wash off the insects from the bush with strong water pressure from a hose, and then treat the leaves with a soapy solution.
Collect adult insects with a hand-held vacuum cleaner.

These are only temporary measures that are not able to completely destroy insects, but can significantly reduce their number before further control.

There are various ways to combat whiteflies: mechanical traps, traditional methods, biological agents and chemicals.

It is better to get rid of insects using chemicals at the last moment, if other tried means have not given the desired result.

Mechanical traps

Traps for whiteflies can be bought in specialized stores or made with your own hands:

Paint a plastic bottle orange, cover the outside with a layer of sticky glue or a mixture of Vaseline and laundry soap (1:1). Light it from the inside and hang it in the greenhouse at the growth level of the cucumber bushes. The midges will fly to the light and stick to the surface of the trap.
Place a light bulb with a red or orange light in a small wooden box (or paint a regular light bulb). Hang the structure in the greenhouse and place a container of water under it. Whiteflies will fly into the light, get burned by the light bulb and fall into the water.

Reference . Such traps are capable of exterminating up to 80% of adult pests in a greenhouse.

Traditional methods

Gardeners who encounter whiteflies on cucumbers are always interested in how to treat the plants against the pest without resorting to chemicals. For such purposes, there are folk recipes against white midges:

Soap solution . To spray and wipe the leaves, use laundry or tar soap. It is mixed with water in a ratio of 6:1.
Sugar solution. 100 g of sugar is dissolved in 400 ml of water. The mixture is treated with infected leaves. If the remedy does not help the first time, repeat the procedure after a week. 5 days after treatment, thoroughly wash the leaves to remove the sugar film.
Lemon infusion . 100 g of lemon peels are poured into 1 liter of water for 24 hours. Add 60 g of soap. After this, the infected leaves are sprayed with a solution from a spray bottle.
Garlic infusion . Finely chop 300 g of garlic cloves and fill them with 1 liter of water. Leave in a dark place for 5 days. Then 5 g of the resulting solution is again diluted in 1 liter of clean water. Spraying is done using a spray bottle.
Dandelion infusion . 80 g of dandelion leaves and roots are poured into 1 liter of water and left for about 4 hours. After this, the solution is filtered and the infected leaves are sprayed with it.
Infusion of yarrow. Add 100 g of yarrow herb to 1 liter of water and leave for 2 days in a dark place. Then the infusion is filtered and the cucumber beds are treated with it.

HOW TO FIGHT WHITEFLY, WITHOUT CHEMICALS!!!!!!! IN A GREENHOUSE, WITH AVAILABLE MEANS, A SIMPLE METHOD

Biological agents

An interesting biological way to exterminate whiteflies is to include other insects in the fight against it. In nature, white midges and their larvae are hunted by, for example, ladybugs and lacewings. To attract them, marigolds are planted next to cucumbers.

There is also an insect in nature that parasitizes whitefly larvae. This is an encarzia - an ichneumon rider from the order Hymenoptera. She lays her eggs directly into the white midge larvae, thereby destroying them. Insects are populated in the greenhouse at the rate of 20 individuals per 1 m2.

Important ! Villi on the leaves of cucumbers prevent encarsia from reaching the whitefly larvae, so this method may not work to its full potential on this particular crop.

The biological preparation "Verticillin" contains a fungus that can kill both larvae and adult whiteflies. At the same time, it does not cause any harm to plants, animals and humans. The drug “Fitoverm” will also help in the fight against pests.

Chemicals

If the previous methods did not help or the whitefly infestation has reached significant proportions, you will have to resort to chemical means.

The most effective insecticides against whiteflies include:

" Aktellik ". Sold in ampoules. The contents of one ampoule (2 ml) are dissolved in 2 liters of water and sprayed. Up to 2 treatments are allowed. Protective effect in a greenhouse is 10–12 days.
" Arrivo ". Consumption rate: 1.5 ml per 10 liters of water. Protective effect - 10–14 days.
"Bona Forte " (insecticide). The contents of the ampoule (2 ml) are dissolved in 0.5 l of water. Valid for 2-3 weeks.
"Inta-Vir" . 1 tablet per 10 liters of water. Up to 3 treatments.
" Spark ". First, ½ tablet is completely dissolved in a small amount of water, then diluted with water to 5 liters. Repeated spraying is possible after 20 days.
" Confidor ". 1 ml per 5–10 liters of water. Protective effect - 15–30 days.
" Talstar ". 0.6 ml per 1 liter of water. Protects the culture for 2-3 weeks.
" Tanrek ". 5 ml per 10 liters of water. Pour 1 liter of liquid into a plastic bucket, add 5 ml of the drug, mix, dilute to 10 liters. The effect lasts up to 4 weeks.
" Fas " (insecticide). ½ tablet per 5 liters of water. The interval between treatments is 15–20 days.
" Fufanon ". 13 ml per 10 liters of water. Protective effect – 5–10 days.

You can eat fruits after treating cucumbers with chemicals only after a month. In the case of biological products - after 2-3 days. Diluted chemicals cannot be stored.

Important ! When handling chemicals, wear a respirator. Make sure that the drug does not come into contact with exposed skin. It is better to throw away gloves after use. Wash your hands, face and eyes with soap.

Most insecticides repel all insects, including bees, so cucumbers should not be treated with them during the flowering period.

Useful traps

Such traps are necessary for more mature individuals. Moreover, for some gardeners they are much more convenient than folk remedies or chemicals.

In order to catch the pest, you need to use glue bait. This can be plywood painted in a bright color, plain paper or cardboard. Apply some sticky substance to any surface. This is usually castor oil or a special glue that can be purchased at a hardware store. Fly strips can also be used, but experience has shown that they will not have much effect.

Another useful trap is a medium-sized box with a light bulb. It would be better to paint the light bulb in bright colors. For example, yellow or orange. The light bulb is fixed in the middle of the box, making holes in it at the same level. Place a container of water or other liquid on the bottom of the box.

The scheme is completely simple: butterflies fly towards the light, towards a light bulb, get burned and eventually drown.

Features of wrestling in open ground

In open ground, whitefly infection most often occurs through seedlings. Before planting, carefully inspect the seedlings for insects or signs of their presence.

To prevent infection of cucumbers in the garden or plot, the “Bud” product is suitable. Dilute 10 g of the drug in 10 liters of water and spray vegetables every 10 days.

If you find whiteflies on cucumbers in open ground, first wash them off with water and loosen the top 2 cm of soil. Then treat the plant several times with a soap solution and insecticide. Iskra is well suited for these purposes.

Spraying should be carried out in dry, windless weather, in the morning (before 10:00) or evening (after 18:00), when the plants are not at risk of sunburn.

Unpleasant consequences of pest infestation

The consequences of whitefly infestation of cucumbers are not the most pleasant.

Find out also how to water cucumbers in a greenhouse correctly and how often.
Among the damage that a pest can cause to a plant are the following:

slowing down the growth of the bush;
decrease in yield;
drying out of foliage and its gradual fall;
disruption of the photosynthesis process;
attracting other diseases, such as fungal and viral infections, or insects such as ants (due to the deposition of honeydew on leaf blades).

Preventive measures

To prevent the appearance of whiteflies on cucumbers in a greenhouse, a number of rules should be followed:

Use traps. A bright surface will attract insects, and a sticky surface will prevent them from escaping.
Experienced gardeners recommend using the “Bud” product for prevention.
Carefully inspect the seedlings before planting in the ground. Purchase seedlings only from trusted manufacturers. Check the leaves before purchasing.
After harvesting, carefully dig up the soil and remove all plant debris and debris.
Treat the soil with bleach or copper sulfate. Fumigate the greenhouse with tobacco smoke. Treat the frames with Bordeaux mixture.
Freeze the greenhouse in winter: open it for 1-2 days when the temperature drops below -12...-15 °C. In such conditions, insects die.
Do not plant plants very densely and avoid extreme heat and humidity in the greenhouse. You can stretch a gauze mesh over the windows in the greenhouse.

Don’t be lazy to carry out prevention, and then the whitefly will not be scary for your cucumbers.

Forget about whiteflies in your area! An easy solution to your whitefly problem.

Causes of white midges and harm to cucumbers

Favorable conditions for the development of insects are high humidity and warmth. In addition, the insect overwinters on the site, waiting out the cold in the remains of garden and weed plants. The cause of infection of cucumbers is neglect of cleaning the site at the end of the gardening season and cloudy weather without sudden temperature changes. And in the greenhouse - non-compliance with sanitary and hygienic measures, lack of ventilation and excessive watering.

Reviews

All these methods have been repeatedly tested by gardeners who have at least once fought against whiteflies. Not every method bears fruit, and sometimes new solutions appear that unexpectedly lead to victory.

Galina, Kazan: “What if you use a sulfur bomb to treat a greenhouse? Every autumn I light 3 checkers at the same time (I have a large greenhouse). And in the summer I make tobacco smoke in the greenhouse - it doesn’t harm the plants, but the effect is excellent! There are no whiteflies..."

Tatyana, Voronezh region: “ Last year I was in a greenhouse in the summer, but I couldn’t destroy it. In winter I kept the greenhouse without snow; I added snow only in February. I didn’t see it in the greenhouse this summer. So it’s not all that bad.”

Natalya, Perm: “I only had whiteflies in the first year of my gardening. Then I started hanging up bottles of iodine - there were no pests or late blight.”

Margarita, Tyumen: “ I’m militantly determined for the summer of 2022!” I've been on the warpath since the fall! First of all, I treated the diseased (and not only) bushes behind closed doors. The next day I dug up all the bushes, took them far beyond the site and burned them! I dug up the ridges when it got cold and didn’t cover them with snow. I wanted to freeze this disgusting thing, but it’s not for nothing that they say - be afraid of your wishes! The winter turned out to be fierce: 10–15 centimeters of snow fell during the entire winter, and the frost was -50! Not only the whitefly froze - 90% of the perennial flowers, almost all the vegetables in the cellar. So I won this war at the cost of great losses, but there were no whiteflies in my greenhouse in the summer of 2022!”

Yuri, Chelyabinsk: “I struggled for six months, all to no avail, nothing helps. The fumigator (Transflutrin liquid) unexpectedly helped. All those flying died within a day. It does not affect larvae and eggs, you need to wait until the butterflies hatch. We close the greenhouse tightly, turn on the fumigator in the evening (at night), turn it off in the morning, repeat every other day, and so on for a month (preferably two). The effect is 100%.”

Chemical control methods

Extensive damage to the area inside the greenhouse or in the garden does not allow the use of the techniques described above. Chemicals are the only methods of effective pest control that will help. The first rule is to adhere to the dosage indicated on the drug packaging. The concentration level must not be exceeded, otherwise the crop will die. List of effective drugs:

"Akarin" is a substance with a wide spectrum of actions. Penetrates into the structure of the plant. As soon as the pest tries to feed on the sap of the seedlings, it absorbs the poison.
"Aktara" - affects larvae and adults. Seedlings are sprayed once every 5 days.
"Admiral" is a broad-spectrum product. It worked well when the garden was affected by a large colony of midges. Penetrates into the soil to great depth. Kills larvae, young animals, adults.

Symptoms of the lesion

It can be quite difficult to see whiteflies on cucumbers in the initial stages of infection. But you can suspect the presence of a pest based on indirect signs. In particular, the presence of an insect is said to be:

whitish spots on cucumber leaves;
numerous translucent yellow-white scales on the back of the plates;
yellow and black-brown areas on leaves and stems.

If you move the shoot of a cucumber infected with whitefly, the insects will begin to move and they will become clearly visible.

The whitefly flies low above the leaves of cucumbers and moves from bush to bush with short jumping movements

Prevention in a repeatedly infected area

In greenhouses and open ground, where the pest has appeared more than 4-5 times, a more radical means of protection against its repeated visits will be required. A radical way to get rid of midges is cold. A slight temperature difference leads to the death of adults and young animals. The summer resident closes the greenhouse and cools it to -20 C. There is a misconception that freezing can be replaced with snow. It is worth opening the roof of the greenhouse so that the soil is under a white blanket.

The whitefly feels great under the snow. For years the insect remains dormant under a warm blanket. Only sharp cooling to – 15 C – 20 C will destroy the pest. The duration of the “thermal shock” is 12 hours.

On a note!

The described method is useless if the region has a mild winter. An alternative to cold prevention would be disinfection in the fall and spring. 3 weeks before the intended planting, the garden is fumigated.

Whiteflies that appear on cucumbers will destroy the crop in the greenhouse in 1-2 weeks. The adaptive insect is practically impervious to chemicals at the pupal stage, which makes control difficult. Regular inspection will help prevent crop destruction. As soon as white dots are found on the bushes, they are immediately removed. The effectiveness of treatment often leaves much to be desired. Regular prevention will help you avoid risks.

Infection can be prevented

They begin to operate in the fall. After completing the harvest, the greenhouse walls and soil are disinfected. A concentrated infusion of potassium permanganate will complement a specialized product purchased at a gardening store. The next step is to cover the soil with a protective film. If there are easily accessible places where the pest can penetrate, they are treated with any disinfectant composition.

On a note!

Its packaging should indicate that it even dissolves the protective shell of the insect egg.

The drug “Intar-Vir” and KRA aerosol have proven themselves well. If a summer resident does not want to water the garden with “chemicals,” then they prepare a folk prophylactic remedy. A mixture of industrial alcohol and water in a 1:1 ratio is poured into a bucket. Water the area with the prepared mixture. Adults and young animals have no chance.

Every corner of the greenhouse must be treated. If you leave 1 dirty area, the insect will manifest itself next year. Another folk method is used to spray seedlings. 3 tablespoons of alcohol (96%) are dissolved in 1 liter of clean water. Other preventative recommendations:

Hormonal chemicals (“Match”, “Admiral”) are effective in the fight against larvae and young animals. Useless if adults have previously been found on the site.
Alkali is a substance that is destructive to pests. It is enough to dig up the soil immediately after harvesting and 2 weeks before planting a new one. During this manipulation, slaked lime is added in a volume of 100 g per 1 m².
Fumigation - suitable only for greenhouses. Two options for the development of events. The first is to buy a ready-made checker at a garden supply store. It doesn't matter whether they use sulfur or tobacco. The smoke is safe for humans and seedlings. The second scenario is to make your own fumigation composition. Take a metal tray and sulfur at the rate of 80 g per 1 m² of surface. The greenhouse is closed and the substance spread on the surface is heated. The smoke even penetrates underground, destroying the pest.

Sulfur bomb is a preventive method that is suitable for use in a large greenhouse. The treatment is carried out in the evening, when there is no wind or rain. Before starting work, put on a protective mask and suit.

Prevention of pest occurrence

There will be no problems when growing cucumbers in open or closed ground if you follow the rules of agricultural technology. The crop is grown in loose, permeable soil; it is not planted in lowlands or in places with high groundwater levels. Select an area that is well lit and ventilated.

Cucumbers are planted according to the scheme indicated in the description of the variety or on the package with seeds. Timely feeding is the key to plant health; weakened bushes are more susceptible to whitefly damage.

Attention! When plantings are very dense, cucumber bushes are poorly ventilated. The thickets constantly maintain high humidity - an ideal environment for the life of whiteflies.

The bushes are formed, excess shoots are removed, yellowed leaves are trimmed, and the vines are sent along the trellises. The greenhouse is regularly ventilated to prevent harmful insects from flying into the room; doors and windows are covered with mosquito nets. Cucumbers are moisture-loving, but water them moderately and do not allow the soil to become waterlogged. Watering on the leaf is permissible only in the exhaust gas (in the morning). They keep the beds clean, remove weeds in a timely manner, and periodically replace old mulch with fresh ones.

Even if it was possible to destroy the whitefly this season, there is no guarantee that it will not appear next year; perhaps some of the eggs are preserved in the soil. How to prevent the pest from reappearing:

In autumn or early spring (a month before planting cucumbers), remove all debris and plant debris, dig up the soil using a shovel, and break up the lumps. All internal surfaces of the greenhouse are washed with a solution of copper or iron sulfate and lime (200 g per bucket of water), and the soil is spilled with it, 10 liters is enough for 2 m² of land.
Instead of vitriol and lime, you can use potassium permanganate. To treat surfaces and soil, prepare a dark pink solution.
The insect dies at temperatures below -10°C. In the fall, after harvesting plant residues, the greenhouse and soil are treated with chemicals (regular and hormonal) or copper sulfate and dug up. As soon as severe frost sets in, open the windows and doors in the greenhouse, leave them like that for 2-3 days, then close them again.

Disinfectant mixtures are also suitable for treating soil in exhaust gas. Copper sulfate is used once every 5 years; copper accumulates in the soil and helps reduce the yield of cucumbers. Often the source of whitefly is seedlings, especially purchased ones. About 15 days before planting, all seedlings are watered twice and sprayed with a weak (light pink) solution of potassium permanganate or a biological product against pests. To destroy some of the larvae that have entered the soil for the winter, the beds are dug deep in the fall.