A spider mite on cucumbers in a greenhouse is a dangerous polymorphous pest - polyphage. It is detected in the final stages of the growing season. Active until harvest.
The common spider mite Tetranychus urticae Koch occupies one of the most significant places among phytophages. In protected soil it is capable of active reproduction, rapid change of generations. It multiplies well on melons and gourds, potatoes, radish, celery. Tomatoes, onions, cabbage and sorrel are of no interest to him.
With a free choice of fodder substrate from all garden crops, prefers cucumbers. Mite on cucumbers in the greenhouse as a pest is able to distinguish varietal characteristics and choose the least resistant to pests varieties.
In the greenhouse creates a favorable habitat for the tick:
- large amount of feed substrate;
- optimal temperature and humidity conditions;
- wind and rain protection;
- lack of natural enemies.
In the open ground the greatest damage is caused to farms that cultivate soybean and cotton.
Ticks spread with cobwebs on the air currents. They are carried by humans and animals. Penetrate from other already infected garden structures or with seedlings. Winter is well tolerated.
In the male, the body is elongated, strongly narrowing towards the end, up to 0.35 mm long. The female mite has an oval body up to 0.45 mm long, with 6 transverse rows of setae. Females laying eggs are painted green.
During the period of diapause (temporary physiological rest), their body acquires a red-red color. The presence of diapause in spider mites complicates the fight against it.
Females in the period of diapause overwinter in shelters: in the cracks of the inner surfaces of greenhouses, in the soil, on all vegetative parts of weeds. With increasing temperature and humidity, as well as increasing daylight out of diapause. Intensive reproduction begins, mainly near the structures of the greenhouse and along its periphery. During the planting of seedlings in the ground there is a rapid resettlement of active females over the entire area of the greenhouse.
Results of tick life:
- Having settled on the inner side of the leaves, the spider mite begins to feed heavily on sap, mechanically damaging the cells. Then moves to the outer part of the leaf, on the stems and fruits. The top tier of plants suffers the most.
- A web weaves leaves and stalks. Respiration and photosynthesis are inhibited.
- Necrosis develops. First there are single white dots, then a marble pattern. The leaves turn brown and dry
- Yields are significantly reduced.
Females in 3-4 days lay their first eggs. One female produces 80-100 eggs. She is able to give in the greenhouse up to 20 generations. Most actively reproduce at a temperature of 28-30 ° C and a relative humidity of not more than 65%.
Plant Protection and Prevention
If the tick settled on cucumbers in greenhouses, you need to know how to fight. Pesticide and acaricidal agents are used to destroy phytophagus.Important! After several treatments, the pest resistance to drugs develops.
Chemical protection against ticks is also undesirable because it is not possible to obtain environmentally friendly products - pesticides do not have time to decompose.
In a private greenhouse you can use biological products by spraying:
- Bitoxibacillin or TAB, with an interval of 15-17 days.
- Fitoverm or Agravertin, CE with an interval of 20 days.
Biological drugs are the least aggressive.
The most safe and effective method of struggle is the use of natural enemies of the tick.
In nature, there are more than 200 species of insects that feed on spider mites.
- Effective use of arkarifag - predatory mite phytoseiulus. 60-100 animals are enough for 1 m². The predator eats ticks in all phases of their development: eggs, larvae, nymphs, and adults. Acarifag is most active at a temperature of from 20 to 30 ° C, humidity over 70%.
- Ambliceius Svirsky is another species of predatory mite, which is used for large concentrations of pests. This predator is not picky about environmental conditions - it is active at a temperature of from 8 to 35 ° C, humidity of from 40 to 80%.
- Another enemy of spider mites is the predatory mosquito of the family Cecidomyiidae.
Environmental measures allow you to grow crops without pesticides.
Before planting seedlings need to carry out maintenance work.
- To prevent the spread, it is necessary to thoroughly destroy weeds (first of all, quinoa, nettle, shepherd's bag), both inside the greenhouse and beyond. Conducted deep cultivation of the soil in the greenhouse. The top layer of the earth is removed, it is disinfected or replaced with a new one.
- All structures of the greenhouse must be disinfected with an open flame of a gas burner or blowtorch.
- Do not allow excessive thickening of landings.
- It is desirable to grow in greenhouses varieties of cucumbers, resistant to spider mites. The species with the leaves that have the greatest thickness of the epidermis and the lower friable part of the leaf pulp, the spongy parenchyma, are least vulnerable. Long and tight hairs limit the feeding of the tick. Varieties that are able to accumulate nitrates (for example, Augustin hybrid) are eaten first by the tick. Phytophagous hybrids of cucumbers, whose chemical composition is dominated by solids and ascorbic acid, do not like.
Some vegetable farms conduct pre-sowing seed treatment:
- heating for 24 hours at t 60 ° C;
- calibration in salt solution;
- then keeping for 30 minutes in a 1% solution of potassium permanganate with immediate washing and drying.
Before germination, seeds are soaked for 18-24 hours in a solution, which includes:
- 0.2% boric acid;
- 0.5% zinc sulphate;
- 0.1% ammonium molybdate;
- 0.05% copper sulphate.
When a tick is found on cucumbers in a greenhouse, it is necessary immediately to deal with it, as well as to prevent it.