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Video: Plant Pesticides - Advantages And Disadvantages
Working with herbal preparations requires extra care
I have been working in the field of plant protection for over 30 years. And I want to say that, analyzing scientific and popular science literature for an even longer period of time, I am always amazed at the paucity of scientific research on widely advertised insecticidal plants, which have recently been offered as an alternative to the chemical method of pest and disease control.
Numerous books with recommendations and individual chapters in others devoted to this issue, unfortunately, are, as a rule, purely perlustrative in nature: from year to year, from one "textbook" to another, the same material is rewritten. When asked a question to one of the authors of such a book, he referred to information more than fifty years ago! By the way, a similar one-sidedness of the materials submitted by the authors is observed when familiarizing with the literature concerning the medicinal properties of various plants - indoor and outdoor. But often a plant that exhibits some useful properties in some human diseases is at the same time capable of stimulating the development or activation of others. It turns out that here we are acting according to the principle: we treat one thing and cripple the other. True, it is possibleassociated with the amateurishness of the authors or their ignorance of the entire volume of the issue presented.
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Over the past twenty years, folk remedies have been actively promoted - plant pesticides. Many gardeners and gardeners actively use various decoctions and infusions of insecticidal plants against pests in their backyard plots. But in recent years, the opinions of experts on the appropriateness of such funds were divided. Among them there are many scientists who in their latest publications adhere to a rather negative assessment of them, they even talk about the harm of such use of these plants.
Folk methods of plant protection originated a long time ago. For example, with the advent of tobacco in Europe, farmers began to actively use its extracts against weevils - pests of fruit trees and berry bushes. After the delivery from Persia to Russia (more than 150 years ago) of Dolman (Caucasian) chamomile, its inflorescences, which contain pyrmethins, began to be used as an insecticide against household and garden pests. 100 years after the appearance of this plant in Europe in agriculture - in the 30-40s of the twentieth century - solutions of nicotine and anabasine sulfates, produced from this chamomile, were widely used. But in our years they have long been removed from the "List of recommended drugs …" as highly toxic.
Of course, herbal raw materials will be used in the chemical industry and in the future when developing safe products for us. This is due to the fact that the negative consequences of chemicalization are becoming more and more noticeable - environmental pollution, the growth of resistance to pesticides in harmful organisms. So the interest of scientists in the development of new pesticides from an almost inexhaustible variety of plant materials is growing. For example, it is considered more efficient to create plant pesticides that rapidly decompose by microorganisms, say, phytoalexins. These are protective compounds of a broad spectrum of action, produced by plant cells in response to the introduction of harmful objects into tissues. But, as it turned out, unfortunately, not many such compounds are formed by plants. Therefore, it is advisable to work more with plant extracts, i.e.with compounds obtained from them that are toxic to pest organisms. Such substances of plant origin include alkaloids, phenols, saponins and essential oils. However, they decompose quickly under environmental conditions (especially when exposed to sunlight).
It is for this reason that to replace them, scientists began to develop synthetic analogs that are more resistant to the external environment. The analogs of pyrethrins from Dolman chamomile are insecticides already known to many gardeners - decis, fastak, inta-vir, arrivo, sherpa, kinmix, rovikurt, fury, sumicidin and others.
In addition, it should be noted that the ease of using herbal decoctions at home is quite deceiving. Sometimes fermentation or infusion of plant mass takes 7-10 days. In addition, they sometimes need to be mixed daily. And for drying plant materials, harvested if necessary in large volumes, a separate room is required, isolated from children and animals. And yet, the resulting dust-like fraction remains suspended in the air for a long time. But pharmacists (doctors and veterinarians), who actively use even the most poisonous plants in their practice, work only in special laboratories in compliance with all safety rules. And it is no coincidence that even Peter I (in 1701) prohibited the sale of medicinal plants from hands,and an order was issued to concentrate it in 8 special pharmacies.
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Of course, it seems almost impossible to entrust the preparation of infusions and decoctions from plant material for the needs of the population of the entire country only to licensed persons or herbalists, as some experts suggest. However, it would be nice if these recommended plant pesticides underwent a complete environmental and hygienic assessment, like all synthetic drugs, non-harmful microbiological products, and genetic engineering products. Therefore, it is natural that many plant protection specialists are surprised and even protest against recommendations on the use of infusions and decoctions not included in the "List …".
Scientists are of the opinion that it is safer to use the so-called "repelling" plants in the household sector, the substances of which (for example, volatile essential oils) act on the sensory organs of insects and vertebrates. After all, it is known that the bushes growing nearby or the elderberry branches simply placed in the water scare away moths, moths and a number of bud mites from the currant. And on mice, marigolds, garlic, turnip onions, sea onions (woodworms), wormwood, black root, chaff of yellow bitter lupine have the same effect.
Onion and garlic bulbs, stems of wormwood and tansy suspended in the crown of fruit trees are unpleasant for moths, and chives, marigolds, mustard, nasturtium, mint and other aromatic herbs are unpleasant for aphids. But the effectiveness of repelling these plants is largely influenced by weather conditions, the size of trees and shrubs, as well as the number and phase of pests. By the way, according to serious experts, recommendations for scaring away from plants of strawberries and onions "aboveground" leaf, bud and stem nematodes by sowing marigolds, marigolds and chicory damaged by these nematodes are completely unfounded. At the same time, they believe that root secretions of marigolds, Gaillardia, helenium and asparagus can effectively suppress the vital activity of a number of other root nematodes.
Also, along with plants that are relatively safe in nutrition and everyday life - onions, garlic, horseradish, chamomile and dolmat, paprika, stinging nettle and others - poisonous plants are also mentioned in the recommendations - black henbane, belladonna, common dope, high larkspur, comfrey, crocus, spotted hemlock, aconite, poisonous milestone. At the same time, it is known that, for example, 2-3 g of milestone rhizomes are fatal to humans. Umbrella two-year-old hemlock spotted is considered one of the most poisonous plants of the middle lane thanks to the alkaloid horse meat, which is one of the most powerful poisons.
God forbid, if the juice of the nightshade perennial belladonna gets on your hands, face and especially eyes. This plant is especially dangerous for children, who often mistake its black shiny berries for cherries. Even two berries are enough to cause poisoning in children (and adults too), and a few berries - death. The alkaloids of black henbane have such a strong stimulating effect that they can lead to "interesting" hallucinations. Children are often poisoned by it, attracted by seeds similar to poppy seeds, which are especially poisonous. Children, above all, also suffer from intoxication.
I hope I have convinced readers that henbane, belladonna, hemlock and dope are not only unacceptable to grow near housing (not to mention their use for self-medication), but should even be destroyed.
Experts report that, under certain conditions, even processed products of wormwood, hellebore, tansy, milkweed, creeping mustard and celandine can harm health. It is proven that even tobacco dust can cause serious poisoning if it accidentally gets into the respiratory organs. It turns out that the pursuit of cheap plant protection products later turns into problems for their own health. As a result of the illiterate use of a number of herbs, allergies, skin irritations and even disorders of the functions of internal organs occur. By the way, many herbal poisons can accumulate in some internal organs (more often in the liver), and pathological effects often appear only after 5-7 years. It has been precisely found that the alkaloids pyrolysine, senecyphilin and senkirkin (mother-and-stepmother, borage, ivan tea,comfrey) cause severe liver damage. By the way, these plants are prohibited from using in a number of European countries and Australia.
Hobbyists often start picking plants when the time is right for direct pest or disease control. They do not take into account the fact that the concentration of active components varies considerably (up to 500%) even in plants of the same "medicinal species" growing nearby, not to mention the plant collections obtained in different years and in different areas. According to experts, the accumulation of the maximum amount of toxicants is noted in plant tissues before and during their flowering. The concentration of toxic compounds is significantly influenced by the drying conditions: under the influence of sunlight, it decreases and even the destruction of toxicants. When drying is carried out at high humidity, putrefactive and mold fungi may appear on the plant raw material, which are fatal to humans due to the release of mycotoxins.In addition, as a result of global environmental pollution, it is possible for the plant material to enter the plant material during the growing season (both from the soil and from the air) of salts of compounds of cadmium, lead, strontium, which are hazardous to the human body, products of oil and coal processing, and even pesticides. You must also agree that during the preparation of solutions and infusions it is impossible to accurately calculate the concentration of the toxicant (overdose and underweight are possible), therefore instability and extreme inconsistency of the results of application are quite expected.that during the preparation of solutions and infusions, it is impossible to accurately calculate the concentration of the toxicant (overdose and underweight are possible), therefore instability and extreme inconsistency of the results of application are quite expected.that during the preparation of solutions and infusions, it is impossible to accurately calculate the concentration of the toxicant (overdose and underweight are possible), therefore instability and extreme inconsistency of the results of application are quite expected.
So it is quite difficult to agree at random with the use of folk remedies on personal plots. There is relatively much information in the popular scientific press on this score, but there is no scientific confirmation by experiments of the effectiveness of all the numerous decoctions and infusions. Unfortunately, you can often find such recommendations in brochures issued by plant protection stations, which are very limited in conducting purely scientific research.
Good results in protecting their individual crops can be obtained by gardeners who grow certain plants on their site, whose nectar and pollen feed on beneficial insects - tahina flies, wasps, predatory bugs and ticks, soft beetles, ladybugs and others. This makes it easier for gardeners to control ticks, aphids, caterpillars of many pests (including cabbage and white turnip).
And it is no coincidence that recently European countries have begun to produce environmentally friendly herbal preparations (biopesticides) and resistance inductors. For example, the drug "Biosan" is a mixture of sulfur, lime and silicon minerals, extracts from garlic and horsetail, adhesive. It is used in the fight against apple scab, stone fruit moniliosis, powdery mildew of fruit and berry plants.
Plant protection experts warn that "home" remedies made from insecticidal plants are by no means harmless, and advise you to be careful when choosing an alternative to a chemical method to combat harmful objects. It may be much safer (accurately and with high quality) to treat plants with a proven and included in the "List …" drug and get a guaranteed result than to resort to using plant materials of dubious quality.