Growing cucumbers in greenhouses and hotbeds help to get unprecedented crops. But the special conditions of the protected ground – high temperature and dry air – favor the development and mass spread of many pests.
The most harmful of them are red and ordinary spider mites. So what preventive and protective measures should a gardener take so that greenhouse cucumbers do not suffer from a spider mite?
Spider mite – the enemy of greenhouse cucumber No. 1
The spider mite is ubiquitous throughout Russia. He is not fastidious in his diet and is able to feed on the juices of more than 200 different cultivated and weed plants.
This unprepossessing crumb does tremendous damage to plantings of cucumber in greenhouses, hotbeds, and also in an open garden bed.
No less often, mite colonies settle in beds with melons, pumpkins, spinach, peppers, peas, root and petiole celery, parsley, green, and some ornamental plants. Ticks also occur on wild plants: wormwood, field bindweed, nettle, and swan.
This phytophage belongs to the family of spider insects and looks like a tiny spider. The largest individuals grow to a length of about a millimeter (an average of 0.3 to 0.5 millimeters) and have oblong-rounded bodies, the color of which varies depending on the season.
Females of the summer brood are greenish-yellow with a gray tint, with dark brown spots on the sides of the abdomen. Winter females are painted in a uniform reddish-orange color.
After fertilization, the females crawl for the winter under the fallen leaves, plant tops, into cracks in the soil, the cracks of the greenhouse, and between the greenhouse frames.
A week after waking from winter dormancy, female spider mites randomly lay tiny, spherical, yellowish-green, translucent eggs.
The life span of adult female spider mites is only 2-4 weeks. But during this period, each of them manages to lay about 100 eggs. And in just two or four days, larvae from 0.13 to 0.14 millimeters in size appear with an oval body and three sets of paws.
The taste preferences of larvae do not differ from adult specimens of spider mites. By the way, in shelters in the ground and in the gaps between greenhouse constructions, eggs remain viable for up to five years.
The accelerated reproduction of the spider mite on cucumbers is promoted by high temperature – from +24 to +28 degrees – and a moderately low ambient humidity – 35-50%.
Exceeding the temperature indicators of a mark of +32 degrees along with very high humidity (85-90%) causes the death of 25 to 30% of the eggs of this pest.
Development from the egg stage to the adult tick usually requires one to three weeks. During summer, up to 20 generations can form in the closed ground.
The spider mite chooses the lower part of the leaf plate, which it braids with the thinnest cobweb, as its place of residence. The pest draws juices from plants through small punctures.
Traces of its activity are also clearly visible on the outside of the leaf – white spots appear on the feeding sites, which are hardly noticeable to the eye, which subsequently joins in uniformly discolored areas. These phenomena are also often referred to as marbling.
Cucumbers affected by the pest grow slowly and finish the growing season ahead of schedule.
Under unfavorable conditions, the insect females have an unpleasant burrow in the ground or in other secluded places and fall into a kind of hibernation, scientifically called diapause. In this case, all metabolic processes in the bodies are greatly slowed down.
But immediately, when the external conditions improve, the mites come to life and begin to multiply intensively. The rapid development of pests occurs when a dry and warm microclimate is established in the greenhouse.
Measures to combat the spider mite on cucumbers
How to deal with a spider mite on cucumbers?
In this matter, the most important role is played by prevention, carried out immediately after the completion of the greenhouse harvest:
- Make a general cleaning in the greenhouse, during which remove all the remains of tops and weeds from it. It’s better to burn them. It will also not be superfluous to remove the top – from 3 to 5 centimeters – a layer of soil since ticks mainly accumulate in it.
- Do not neglect the thorough disinfection of all internal surfaces of the greenhouse, including garden packaging and tools. To do this, dilute 400 grams of bleach in 10 liters of water and let the mixture stand for 2-4 hours. Pour the upper transparent layer of liquid into the spray gun and thoroughly moisten all parts of the greenhouse where ticks can hide. Use the remaining sediment to coat the greenhouse in the greenhouse. For such treatments, caustic soda is also taken – from 300 to 500 grams of water per the same volume of water.
- Military actions against a spider mite on cucumbers begin when the first signs of pest damage appear. First things first, carefully pluck and remove from the greenhouse all strongly affected individual leaves and give them to the fire. In an extreme case, deeply bury greens with pests.
- The pest spreads to the site on garden tools, clothing, and seedlings. Therefore, it makes sense to start all summer cottage activities from sites not affected by the tick. Around the beds with cucumbers and other pumpkin plants regularly weed out the weeds on which he likes to live and breed.
- Treat spray plants with onion husk infusion. Pour 10 liters of water with a temperature of about +40 degrees into 150-200 grams of husk and let it brew for 10 to 15 hours and, without diluting with water, spray the diseased plants. To keep the solution better on the leaves, I recommend adding 10 to 15 grams of laundry soap for each liter.
- If the onion peel does not have the desired effect, use the help of the biological product Actofit 0.2% according to the instructions.
The modest size does not prevent the spider mite from quickly spreading to very decent distances, therefore it is important to timely detect infected cucumber bushes and to carry out abundant spraying with a natural or store insecticide. Such treatment should cover not only the plants themselves but also all the nooks and crannies in the greenhouse.