How to get rid of spider mites on cucumbers in a greenhouse: proven methods of control and prevention

Spider mites are a dangerous pest that affects cucumbers in the garden and greenhouse. Small colonies grow at tremendous speed and completely take over plantings. Already seven days after the spider mite appears on the site, it can be detected by traces of vital activity on the greenery. Then a cobweb appears on the leaves, in which colonies of insects are located.

In this material we will take a detailed look at the main methods of controlling spider mites on cucumbers in a greenhouse. We will tell you about effective insecticides, biological preparations, folk remedies and frequency of use. You will learn how to use agricultural techniques to prevent infection of cucumbers in a closed space.

Description of the pest

Spider mites (Tetranychinae) are a polyphagous pest that feeds on plants in closed and open ground. It causes the greatest harm to plantings in greenhouses. An enclosed space creates ideal conditions for an increase in the arachnid population.

The small size of the tick, only 1 mm, does not allow it to be immediately recognized. Colonies can only be detected by examining the back of the leaves with a strong magnifying glass.

The color of the body can be red, green-yellow, orange, milky-transparent. Wintering females are large, tan or red in color. Males have a more elongated body. Some individuals with increased nutrition reach a size of 2 mm.

Soft-bodied spiders have an ellipsoidal shape, the upper part of the body is convex, the lower is leveled, flatter.The larvae are transparent, light green or green-brown in color with dark spots on the sides. Adults have four pairs of legs.

Females are fertile and lay up to 500 eggs every 3-4 hours. The eggs are round in shape and immediately after laying they are white-yellow or milky-transparent. During the year, individuals go through up to 12 development cycles. Fertilized eggs produce females, and unfertilized eggs produce males.

The rate of embryo development depends on the air temperature in the greenhouse: at +15°С – 15 days, at +30°С – 48-72 hours. The total life expectancy directly depends on temperature indicators and varies from 2 to 8 days. This feature is taken into account during plant treatments.

With the onset of cold weather, nymphs (pupae) leave for the winter in the form of non-feeding females. Some of them move from bushes to other places for wintering. Some seek shelter below, others take refuge in the upper part of the greenhouse. Therefore, plant treatment, unfortunately, does not guarantee complete destruction of the pest.

Causes

The main reason the appearance of mites on cucumber plantings in a greenhouse - heat and low air humidity. The pest feels comfortable at temperatures of +30°C and above. Most often found in the southern regions when growing cucumbers on the balcony.

Arachnids reproduce most actively on fattening plants (which gain green mass to the detriment of fruits). Fatliquoring occurs for a number of reasons, but most often when there is an excess of nitrogen in the soil.

The pest settles in the dried remains of plants that have not been removed from the site. From them he moves to the cucumber bushes. In spring, when the air temperature rises to + 10°C, females begin to actively lay eggs on the back of the leaves.

First, the pest occupies the upper leaves, then moves to the lower part of the bushes. Often gardeners do not pay attention to the lower leaves. But they become the main breeding ground for spider mites.

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Signs of appearance

The main food of the pest is plant cells. The main sign of its presence is small white dots on the back of the leaves.. A little later, a thin cobweb appears, like a veil entwining the bushes.

With severe damage, the leaves turn white from numerous damages. At the tips of leaves and shoots you can notice hordes of small, moving pests.

As a result of cell destruction, the process of photosynthesis is disrupted. The plant weakens, immunity decreases. Against this background, secondary diseases of cucumbers appear. Ticks are the main carriers of gray mold spores.

Measures to combat spider mites on cucumbers in a greenhouse

How to get rid of a pest in a closed space? For control and treatment, chemical and biological preparations, folk remedies, and predatory mites (Amblyseius and Phytoseiulus) are used. Preventive measures are no less effective.

Chemicals

Chemicals are considered the “heavy artillery”. They are used in cases where other methods have not helped. The insecticide quickly kills the pest, but has a toxic effect on the environment and humans.

The main disadvantage of such sprays is that insects quickly develop resistance. Therefore, it is advisable to change the composition every 2-3 sprayings.

It is important to remember that treating cucumbers alone is not enough to completely get rid of insects.

The intervals between irrigation of bushes depend on the weather. The higher the temperature and drier the air, the more often the treatments are carried out. In summer, spraying is repeated every seven days. This is exactly how long the female needs to develop and lay eggs.

Spraying is carried out in the evening, since the scorching sun promotes rapid evaporation of substances.

Important! When working with Actellik, safety precautions are observed. For protection, use a robe, rubber gloves, a mask, and goggles.

Biological methods and preparations

Biological agents only affect adults. Therefore, spraying is carried out 3-4 times every week.

The list contains the most environmentally friendly and effective drugs against spider mites, which are approved for use during the period of active fruiting:

1. "Akarin" – enteric contact drug with avertin as an active substance. The period of exposure to the tick is 8-16 hours.
2. "Aktofit", "Kleschegon", "Kleschevit", "Fitoverm" with one active ingredient - aversectin. The neurotoxin penetrates the insect's body and paralyzes the nervous system. The drug is not addictive, unlike chemical insecticides.
3. "Bitoxibacillin" – biological insecticide, contains Bacillus thuringiensis var. thuringiensis. Treatment is carried out twice a month during the growing season. The product does not accumulate in green mass and fruits.

Reference. Treatments with a mixture of “Actofit” and “Bitoxibacillin” show high efficiency.

When growing cucumbers indoors, mites - Amblyseius and Fitoseiulus - are used for control. These are the pest's natural enemies. You can buy them at flower shops.

When used correctly, predatory insects can destroy up to 95% of pests. Two weeks before planting cucumbers, about 50 amblyseius per 1 m² are released in bulk in the greenhouse.The insect's lifespan is 20-25 days.

The predatory mite phytoseiulus (Phytoseiulus persimilis) is distinguished by its rapid reproduction and voraciousness. The effectiveness of the arachnid increases with high air humidity and moderate temperature in the greenhouse. With minor damage, 10-15 phytoseiulus per 1 m² are released, and with extensive damage, 30-40 individuals are released, closer to the source of infection.

Plants that repel spider mites

Plants are planted next to the cucumber plantings in the greenhouse to repel the pest. The method is used in combination with treatments with biological, chemical preparations and folk remedies. Such plants are unable to cope with the task on their own.

Considered the most effective: calendula, marigold, wormwood, parsley, mint, garlic, onion, yarrow, cyclamen.

Reference. Moss or bark is used to repel spider mites. The raw materials are treated with boiling water for disinfection and dried. Then they are buried in the ground under the bushes.

Folk remedies

Herbal-based folk remedies help repel pests, but are not able to completely destroy them. They begin to fight with folk remedies during the period of active fruiting of cucumbers, when acaricides are prohibited.

Spraying is carried out on the back of the leaves. This is where the pest hides.

Agrotechnical techniques for preventing infection

Proper agricultural technology for cucumbers is also effective in controlling the pest:

• frequent weeding and loosening of the soil;
• moderate watering;
• timely application of potassium-phosphorus fertilizers;
• monitoring the level of nitrogen in the soil;
• removal of plant residues;
• maintaining distance when planting (sowing);
• crop rotation;
• disinfection of greenhouses with sulfur bombs;
• treating the soil with a 0.5% solution of copper sulfate (50 g per 10 l);
• humidity level control (optimally above 80%);
• air temperature control (+25-27°C);
• choosing cucumbers that are resistant to spider mites;
• removing the top layer of soil (15-20 cm) and replacing it with a new one.

Varieties resistant to spider mites

The most resistant to mite damage are varieties and hybrids with hard fibrous leaves. They do not have complete protection against spider mites, but biologists are working hard in this direction.

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Conclusion

To quickly get rid of the poutine mite on cucumbers in the greenhouse, chemicals are used that destroy the pest at all stages of development. It is customary to alternate medications, since pests quickly develop resistance.

Biological treatments make it possible to obtain environmentally friendly products, but only affect adult individuals. Predatory mites (Amblyseius and Phytoseiulus) do an excellent job and destroy spider mites in the greenhouse by 95%.

Folk remedies are used to repel pests. Preventive measures are effective before planting seedlings; they prevent the spread of the mite.