Prevention - the basis of the fight against whiteflies in greenhouses
Whitefly - a tiny, 1.5-3.0 mm insect with translucent wings of fairy elves, is a formidable pest of green plants, especially in confined spaces. No, even the most poisonous chemicals can destroy the whitefly "in the bud." Every year, she returns with rare tenacity to the greenhouses and causing the need for a new wave of merciless, and sometimes useless struggle with her. Why is this happening? What measures are needed to clear the greenhouse and surrounding area from whitefly attacks?
Big problems with the protection of vegetables and other crops from whiteflies in greenhouses most often arise in beginner gardeners. It seems that if you spray the plants several times with a strong pesticide, then the whitefly is over! Not! In the process of natural development, whitefly has developed a unique ability to survive. And there are two such moments in the cycle of its development:
- oviposition protected by a special waxy substance, invulnerable to pesticides;
- the nymph stage, in order to save life and “give birth” to the egg-laying stage of insects, it ceases to feed and is also covered with a wax-like substance, inaccessible to the vast majority of pesticides. The hatching female during the allotted period of her life manages to lay several tens of protected egg-laying, in which the survival of the larvae is up to 90%. For all stages of development, about 80-90% reach the stage of nymphs - a whole army of pests. During the season, whiteflies manage to form 15 or more generations, the development cycle of which is only 25 days. In the fall, she goes to any gap where she calmly endures bad weather, especially under thick snow cover.
An analysis of the literature and their own experience has shown that those who fail to get rid of the whitefly and return to the greenhouses again and again violate the basic rule of combating this pest. To destroy the whitefly, it is necessary to annually carry out a full cycle of preventive work, including autumn and spring treatment of the greenhouse and the surrounding area.
For tips to work, they need to be fully implemented. Separate lines, doses, treatment periods taken from articles will not have a positive effect. Most often, this effect will be limited to only one season.
Carry out all the preventive autumn work in the greenhouse.
Empty the greenhouse completely. If necessary, cover the soil with foil and disinfect all internal greenhouse parts. The processing of hard-to-reach corners, crevices, interframe spaces, etc. is very important. Accessible places can be painted, and in hard-to-reach places you can blow out a disinfecting solution. Against whiteflies, this should be a substance that dissolves the protective membrane of the ovipositor:
- Creolin solution (cypermethrin), which acts as Mospilan, Shar Pei, Inta-Vir,
- aerosol ("KRA - deo super"),
- a solution of technical alcohol (vodka) with water in a ratio of 1: 1. The mixture dissolves the protective shell of the masonry and destroys whitefly eggs. A solution of alcohol with water destroys whiteflies well at any stage of development and when spraying plants. Dissolve 2 tablespoons of 96% alcohol in 1 liter of water and spray the plants.
Literally wash all hard-to-reach spots (remember, the size of the whitefly does not exceed 3 mm, and any gap is accessible to it).
- 2-3 days after the first treatment, repeat spraying of all parts of the greenhouse with Actara, which will have an additional effect and destroy all offspring of whiteflies, including adults.
- Effectively use hormonal chemicals, such as Match, Admiral. But their action is aimed only at the destruction of eggs and larvae. For adults, these drugs do not work and require additional treatment against adults. It can be additionally treated with Actara, Actellic, Sharpei, Tanrek and other chemicals.
Processing the greenhouse is best done in the evening, in calm weather, taking all measures of protection against toxic substances (glasses, respirator, bathrobe, trousers, boots, headgear).
After finishing the treatment of walls and all floors, you need to disinfect the soil.
Whitefly does not tolerate alkaline environment. Therefore, first they dig the soil with the introduction of slaked lime, ash, and other powder products. Sprinkling soil with slaked lime is carried out at the rate of 100-200 g / sq. m area and dig into a layer of newly introduced soil or 10-15 cm. Ash - 2-3 glasses per square. m. Other substances contribute in accordance with the recommendations.
The last fall chord of work against whitefly is fumigation of the greenhouse. For fumigation, you can use special Pawn-S smoke bombs, sulfur bombs or Hephaestus tobacco bombs. The latter can be used in the growing season of greenhouse crops. Smoke does not harm plants. If there are no checkers, you can fumigate with sulfur, spread on metal baking sheets at the rate of 50-80 g / cu. m of greenhouse space. The greenhouse must be well insulated. After 2-3 days, aerate. When fumigating, gas penetrates the soil, causing the death of wintering larvae and adults. Please note! Whitefly eggs do not harm eggs. Additional tillage is required.
Whitefly and its offspring cannot tolerate low temperatures, therefore, after the measures taken, it is effective to freeze the greenhouse, lowering the temperature in it to minus 15 ... 20 * С. Some greenhouses believe that if the roof of the greenhouse is open and full of snow there, then this is enough to kill the whitefly. Not! She has a great winter under the snow. Therefore, freezing should be carried out before snowfall or in early spring, removing its excess. Only in the open ground in winter conditions does the whitefly not survive. If the region does not have low winter temperatures, then they carry out all disinfecting measures and finish the preparation (autumn, spring pre-planting) with fumigation.
Preventive cleaning of a near-green area.
It is necessary to remove all rubbish and equipment from the greenhouse and the surrounding area. Clean, rinse, fold into an extension, in which the temperature in winter will be equal to outdoor (natural freezing). Do not forget to pre-sanitize this attachment.
The whitefly can be destroyed in the greenhouse, but it will certainly appear again - from neighbors, purchased seedlings, from weeds on which eggs and adults hibernate. Therefore, it is very important to keep the territory adjacent to the greenhouse in a clean state.
It is imperative to destroy all weeds, especially chafing, nettles, wood lice. A Moorish lawn can be fenced off from neighbors, where plants that attract whiteflies can be bred. A small layer of dill, celery, parsley plants will serve as a natural barrier to whiteflies. Riders, bugs, macrolofus, ladybugs, lacewings and other predator insects that destroy the pest settle on them. You can plant fragrant martinia on the lawn and in the greenhouse. The sticky substance on the leaves of martinia serves as a natural adhesive, on which the whitefly dies. Some gardeners recommend planting in the greenhouses Ageratum Houston (Gauston). We advise you to be careful with this plant. It contains coumarin - a substance dangerous to humans, especially for allergy sufferers. Alkaloid vapors (and it’s hot in the greenhouse) can cause bleeding when it enters the mucous membranes. But this plant can be used outdoors in an improvised lawn or flower garden, where it will successfully exterminate the whitefly. Mint and tansy are attractive for whiteflies. Adults always rush to their aroma. By treating the lawn in summer and mowing for the winter, you can protect vegetables from whiteflies that enter the cottage from the outside.
Dear Reader! The article provides only some ways to protect greenhouses from whiteflies. This article is a reminder that it is possible to fully protect greenhouse crops from pests only when performing a set of works. 1-2 single spraying is only a temporary escape from the problem. More complete materials about whitefly, its development, reproduction and control measures during the vegetative period of plants can be found in the article “Whitefly and pest control measures”.