The problem of weed growth in garden beds is well known to every gardener. If earlier such weeds were handled by weeding the beds, today, thanks to the emergence of effective and completely safe to use herbicides, it is possible to simplify the care of the plantings. Herbicides are agrochemicals that are popular among gardeners, they can significantly simplify the fight against unwanted weeds. With the help of such preparations you can get rid of various weeds, having grown an excellent crop on a personal plot.
The main purpose of herbicides
Weeds not only consume the life-giving moisture from the soil and beneficial micro- and macronutrients, but also contribute to the appearance of various diseases and insect pests. That is why each gardener must weed the beds or use herbicides, which will allow growing delicious vegetables and fruits in the backyard plot.
If in the recent past the struggle weeds consisted in weeding beds and manual removal of such plants, but today, thanks to the use of effective agrochemicals, care for plantings is greatly simplified. Herbicides will save gardener's time, simplifying the cultivation of land on the plot and improving the yield index. At the same time, the use of such effective and at the same time completely environmentally friendly means does not lead to any deterioration in the taste characteristics of the grown crop.
Determination of herbicides
Herbicides are commonly understood as various chemicals, the use of which allows to suppress the occurrence of undesirable vegetation. Such chemicals may consist of one or several components, which allows them to act on a specific weed or to point out and destroy all unwanted herbs and plants in the area.
The most widespread today are the so-called selective agrochemicals, which effectively destroy weeds, but at the same time in no way harm the vegetables and fruits grown in the beds.
In accordance with the classification of herbicides that is widespread today, agrochemicals with biochemical selectivity and compositions of continuous action must be separated. If herbicides of the first type kill only weeds, but they are not capable of harming crops grown in the beds, then continuous chemicals are effective, and they are designed to completely eliminate plants on the plot. Such continuous chemicals are used in the fall when digging up the soil, and in the spring it is already possible to plant the main crops, while in the beds such highly effective chemicals will destroy all the weeds.
Depending on their classification, it is customary to allocate contact and systemic drugs. Contact herbicides do not move inside weeds, but destroy only the plants to which they fall during processing. But systemic drugs can be absorbed by the root system, they move around the plant, destroying both the green part and the rootsdeep in the ground.
Today, the most widespread herbicides of systemic action, as they effectively suppress unwanted vegetation, including the ground and root parts of plants. Such agrochemicals are effective in controlling weeds, which have a developed underground part and are characterized by increased survivability. For example, using such systemic herbicides you can cope with a creeping leek, which can be difficult to remove from the site when using other agrochemicals.
Today on sale you can find three types of such drugs:
- Herbicides, which are intended for the destruction of weeds.
- Algaecides These agrochemicals destroy aquatic vegetation.
- Arboricides. Intend to inhibit the growth of trees and shrubs.
The correct selection of herbicides for the garden
The gardener needs to remember that the effectiveness of their use and the safety of using similar chemistry on the plot depend on the correctness of the choice of such agrochemicals. Choosing this or that means, it is necessary to study the selectivity of the action of such drugs and their nature of the effect on weeds.
When purchasing such weed control products, it is necessary to take into account the prevailing weeds in your area. For example, if there is a large amount of leek on the beds, then contact means will be useless in this case. Note that today you can find various effective herbicides that are completely safe for vegetables and fruits grown on the household plot.
When choosing such agrochemicals, it should also be remembered that selective herbicides, which have a selective effect, are somewhat more expensive than preparations of a continuous action. In that case, if you plan to carry out the treatment of the plot in the fall or you do not plan to grow any vegetables and fruits in the country, you can use powerful herbicides of continuous action. But if you need to pinpoint those or other weeds, then your choice is selective drugs.
Herbicides for the destruction of weeds are an effective means of combating grass. Using the necessary herbicides on the garden plot, it is possible to achieve better fruiting of vegetable ridges in the country, beautiful lawns and flower beds.
There are a great many weeds, they are both annual and perennial. And if it is possible to cope with common grass, if the soil is covered with special material, then it is impossible to cope with long-lived useless plants in this way. Previously, this problem had one solution - mechanical action, that is, weeding. But now there are herbicides and weeds can be managed without spending a lot of effort. The main thing - in compliance with the recommendations on the use of these funds.
The degree of effectiveness of modern drugs
The effectiveness of the use of such agrochemicals will depend on the dosage of the drug, follow the instructions for its use and method of depositing funds. Most of these chemicals, falling on the ground, quickly lose their effectiveness, due to exposure to ultraviolet radiation, oxygen in the air and a number of other factors. Full detoxification of such herbicides is celebrated on the 20-25 day after their introduction. The gardener must take into account the total time of decomposition of the drug, and in accordance with this use one or another tool on the site.
And also noticed that the effectiveness of the use of such funds depends on the preparation of the land and its structure. In the event that in the soil there are a lot of packed dense lumps of earth, then the effect of the drug is significantly weakened. But when using such agrochemicals on well-dug beds with loose earth, the effect of herbicides is very effective.
Soil moisture indicators also directly affect the efficiency of using such agrochemicals. Experienced gardeners recommend even before introducing the drug to loosen the top layer of soil, as well as abundantly polite the earth.
Most manufacturers of such chemicals recommend treating the soil in windless dry weather at temperatures of about 20 degrees. But in the heat or at temperatures no higher than 10 degrees, the efficiency of such processing is significantly reduced.
Proper use of chemistry
Many of us have certain difficulties with the choice of such herbicides for weed control in the area. We offer you the simplest classification of drugs. selective type that can be used by gardeners.
- When growing cabbage, you can use drugs such as Tornado, Stomp, Semeron, Butizan, Panther.
- In the beds where tomatoes are grown, you can use Treflan, Targa, Fuselad, Zenkor, Stomp.
- When growing carrots, you can use Prometrin, Naboo, Furor, Racer, Targa products.
- Eggplant beds can be treated with Treflan.
- For beets, we recommend using Tornado, Dual, Targa, Burefen, Furor, Vitoks.
- When growing cucumbers, you can use Tornado, Targa, Naboo, Dual.
- In the cultivation of potatoes, weed can be fought with the help of Frontier, Fuselad super, Gezagard.
Using certain herbicides in the area, remember that the dosage of agrochemicals must be correlated with the physical and chemical characteristics of the soil in your area.
When using such agrochemicals, it is necessary to remember that they belong to the category of highly active toxic agents, therefore, personal protective equipment should be used without fail.. These include:
- Rubber gloves.
- Gauze bandages and respirators.
- Protective glasses.
- Rubberized or woven robe.
Most of the common herbicides sold in the form of a concentrated solution, it must be diluted before use in water, and then using a sprayer or manually handle the plants and soil. Remember that the use of such tools is necessary in full compliance with the requirements of the instructions, in particular, regarding the maximum permissible concentrations of agrochemicals.
To simplify the processing of the backyard plot, we recommend purchasing a spray bottle or sprayer with a special knapsack that will significantly simplify the processing of the plot. Mechanical manual application of such preparations is also allowed, for which rollers or ordinary brushes are used. In each case, the gardener chooses the method of application of such chemicals, depending on the specific means used and the area of the site and garden treatment for weeds.
Recommendations for use
We offer you the simplest recommendations on the use of herbicides on the plot.
- When choosing such funds, preference should be given to drugs of selective action.
- Of the universal agrochemicals, we recommend Roundup.
- When processing, be sure to use protective gloves, a respirator and goggles.
- The easiest way to do this is with a spray gun and sprayer.
- Herbicide must be diluted in water to the desired concentration and used for 15-20 minutes. But to store a long-cooked agrochemical should not be.
- Full adherence to instructions when applying such agrochemicals of herbicides will make their use completely safe, and the gardener will be able to grow a good harvest on the site.
Adding an article to a new collection
If you have broken a small garden in your plot, you can cope with weeds using traditional weeding. But the owners of 20-30 acres is difficult to do without the use of herbicides. What are these drugs?
The word "herbicides" is derived from the Latin words "herba" - grass and "caedo" - I kill. These are chemicals that destroy vegetation.
By the nature of the action on plants are distinguished:
- Herbicides of continuous action - kill all kinds of plants. They are used to remove vegetation around industrial facilities, on airfields, railways, in ponds.
- Herbicides of selective (selective) action - destroy certain types of plants and do not act on others. These drugs are often used in the garden to control weeds.
Such a division is conditional, since the same substance, depending on the concentration and the consumption rate, can manifest itself as a herbicide of continuous or selective action.
Herbicides are also classified according to goals:
- Herbicides proper - eradicate weeds,
- arboricides - inhibit shrubs and trees
- algaecides - destroy aquatic vegetation.
Depending on the ability to navigate the plant body herbicides are:
- contact - getting to the surface of the plant, they cause damage at the point of contact and almost do not penetrate into the wicked organism,
- systemic - penetrate through the leaves or roots, spread through the organs, causing the entire plant to be affected.
Those substances that are part of the herbicides of continuous action, can destroy all the vegetation that was during the spraying. Such radical drugs are used in areas where vegetation is contraindicated.
The action of herbicides of this species is divided into subgroups, namely:
- • contact drugs,
- • system,
- • soil.
Contact herbicides begin to act on the plant only when the drug has fallen on the leaves or stems. The leaves begin to turn yellow, wither and dry. All this leads to the complete destruction of the weed.
The use of soil herbicides is appropriate in cases where the weed had time to pour their seeds into the ground. Such drugs contribute directly to the ground. They have a detrimental effect on the seeds of weeds, so they do not give them germination.
Systemic herbicides are considered among the most sought-after, as they quickly and effectively affect weed development. When such a herbicide falls on a weed, it not only affects the outer shells, but also absorbs into the plant itself. It spreads throughout the weed, which means that its action is also aimed at the destruction of the root system.
Of course, systemic drugs are incomparable with soil herbicides. Systemic herbicides are able to comprehensively affect the plant, and soil - only on the seeds.
The second large group of herbicides are headed by drugs of selective action. These substances can destroy only certain types of weeds. When choosing such drugs, you must carefully read the instructions for use of herbicides. Often it contains a complete list of weeds, which may be adversely affected by the selected drug.
When buying herbicides for selective action, you need to know:
- • shelf life of the drug,
- • herbicide consumption rates,
- • methods of use.
Can herbicide harm a person? The herbicide instructions always indicate the level of danger and toxicity to humans. All substances that are in the composition of the selected drug, have different degrees of toxicity.
The price of herbicides varies depending on the system of action. The average price of one liter of herbicide can be 200-5000 rubles per 1 liter.
What herbicides are considered the most popular on the market of chemicals? The action of herbicides is directed against weeds, which could be permanent residents of any territory or area for years. Therefore, the fight against them is considered one of the most difficult.
Rereading dozens of reviews of herbicides, we can conclude about the most popular drugs that can really help radically:
• Herbicide Roundup is considered a non-selective systemic drug. It has a wide range of effects, especially on perennial weeds. It is considered one of the most radical drugs in the world. The final destruction of the weed accounts for 14-15 days after treatment.
• Herbicide Tornado aimed at systemic exposure. It is used as a universal remedy for weeds. It contains an increased concentration of the main active ingredient.
• Herbicide Prima is considered a powerful drug that has two active ingredients. Often it is used to control weeds that grow in areas with cereals and corn.
• Gold herbicide applied against grass monocotyledonous and dicotyledonous weeds. It is used in fields with corn, rapeseed, sunflower, soybean, etc.
• The Hurricane Herbicide is a systemic drug that can be used both in the fields and on private land plots. Perfectly shows itself among vineyards, plantations, gardens and fields. It has a wide field of action, therefore it is considered a universal remedy.
• Herbicide Stump is used to control weeds in vegetable beds. It is considered a double-acting herbicide, as it can systemically affect the weed and destroy the seeds through the soil.
• Titus Herbicide is a post-harvest preparation that is used to control weeds in areas where tomatoes, potatoes and corn will be planted. It is considered a systemic drug. It is popular for its low consumption rate, high selectivity and long lasting efficiency.
• Herbicide Zenkor designed for systemic exposure to weeds. The drug has a wide spectrum of action. It has a long protection period. Combats annual dicotyledonous weeds.
• Euroleading herbicide - post-harvest preparation. Sent to the destruction of cereal and dicotyledonous weeds. Acts both through the vascular system of the plant, and through the soil. One treatment will be enough to keep the soil clean throughout the growing season.
• Гербицид Гранстар применяется для очищения от сорняков для ячменя, пшеницы, сорго, сои, рапса. Имеет широкий спектр воздействия. Отлично уничтожает двудольные сорняки, так как влияет системно.
• Gezagard herbicide has a rather long exposure period - 10-12 days. It is used for potatoes, vegetables, corn, coriander, sunflower, cereals. Not phytotoxic.
Why do we need to fight weeds
Answer for yourself the following question: “What is a weed?”. For each gardener, the answer to it may be different. One can count last year's dill as a weed or parsley, which unexpectedly grew out of place, and for the second one, wheatgrass or horsetail fall under this category. But generally speaking, the weed is called grass or flowers that grow in an inappropriate and inconvenient place, and at the same time take away most of the precious light, moisture and nutrients from cultivated plants.
In addition, too much planting density per unit area contributes to the development of serious diseases and harmful insects. In order to avoid this, it is recommended to use herbicides - chemical preparations for weed control. Their use requires specific knowledge, experience and, of course, effort from the gardener. Some prefer to spray each plant individually, while others prefer special solutions, which pour all pest growth.
What types of herbicides exist
In modern gardening, herbicides for the destruction of weeds, of course, the best and most effective way to protect the backyard from unnecessary and annoying vegetation. To date, there are more than three hundred. These drugs are chemically active substances that are used to control the amount of weeds or to prevent their growth.
All herbicides by type of exposure are divided into two types:
- Herbicides from weeds of a continuous spectrum of action, or as they are also called non-selective, capable of destroying almost any varieties of not only annual and perennial weeds, but also useful plants. That is why they are mainly used in those places where cultures do not grow. For example, at the end of autumn after the harvest or in the spring, before the sunrise of shoots. Very often, weed control of herbicides of this type becomes the only possible way for the soil from the vegetation at forest cuttings and stadiums.
- Herbicides selective action from weeds or simply selective. They do not harm crops, but they are capable of destroying most common, not desirable, plants on the site. Due to such properties, selective herbicides can safely be sprayed onto healthy crops and not be afraid for the next harvest.
Attempts to get rid of unwanted perennial vegetation by mechanical means (digging, weeding, disking) often lead to the opposite result: the site is clogged even more. In this case, herbicides from continuous weeds become the only way out in the struggle for the harvest.
In addition, there is another classification: on the basis of appearance and method of application.
There are not two types here, but three:
- The first type - herbicides for the destruction of contact weeds. This type of drug is able to hit the plant with only one contact with its leaves and stem. Such drugs are mainly used to control swan, bristle, gum, biting midge and other annuals, including cereal weeds.
- The next type is herbicides of systemic exposure. Once on the leaves and the root, they spread throughout the plant, thereby ensuring its complete destruction. This type of chemicals is most effective when spraying vegetative weeds with a developed root system, including perennial.
- And the last type is chemical preparations whose action is designed for the early phases of weed growth and extends mainly to the roots and seeds of harmful plants.
It should be clearly understood that the time, method of application and action for a particular type of chemical means depends on their properties, preparative capabilities, the selectivity of crops and the characteristics of the substance in the plant. If you are a novice in gardening, we would recommend you before buying any drugs, with the help of a professional seller of a specialized store. He will tell you not only which herbicides to use in each particular case, but also help you to choose the optimal mixture of these funds.
Interesting. The lemon ants that live in the Amazonian forests kill any green shoots by injecting formic acid into the leaves, which acts on them as well as herbicides against weeds. They do not touch only one tree Duraya. As a result, areas are formed on the banks of the Amazon where nothing grows except for this kind of tree. It looks depressing, and the locals call these forests the gardens of the devil.
A short video on the topic:
Do we need to always deal with weeds?
The removal of weeds with the help of herbicides is in most cases a necessity, but “harmful” and “useless” plants can often become an original decoration of a flower bed or a lawn. The main thing is to approach the issue correctly. "Useful" plants sometimes bring much more trouble, which is why you can always experiment with competitors. And yes, it is better from the very beginning to immediately prepare for the painstaking process.
Before direct cultivation, it will not be superfluous to know all the information. Let's say the choice fell on St. John's wort. It is possible that the beloved cottage will not have the forest, "comfortable" conditions for its further growth. Type of land, habitat, amount of water - it is necessary to deal with this, so that the cultivation was as gentle as possible. In a pinch, you can buy the plant in special stores, all the procedures there have already been carried out.
Why even grow under the nose of these strangers?
It will sound a little ridiculous, but it is a great way to take something interesting for children. Many seemingly useless plants are edible or medicinal and seemingly very bearable, which will positively affect the general mood of the garden and its owners, because at times the shade of light neglect looks very nice. And it is always interesting to know the world, especially if it literally grows under the window.
It would be nice to know about the method of reproduction of the new flower, so that its excessive seeds can stand sideways to the rest of the beds. It will also have to follow the growing season so that unexpected harvests will not be taken by surprise. In principle, the time collected seeds can be used in everyday life, if knowledge and skills allow. In any case, the digging will have to be taken with appropriate seriousness, since the new inhabitant of the flowerbed, whether it has taken root or not, can always be threatened with reprisals by the neighbors.
Any plant, let it grow earlier in the most severe forest, needs care at least for the first time. Otherwise it will inevitably turn into the same weed. The same strawberry, if it is not processed, has every chance to lose its attractiveness and flavor. If you do not pay tribute to raspberries, and it will grow so that it wants, but it will not be so easy to get rid of. Therefore, before getting rid of any shoots, consider whether it can not be useful and whether you should not start to cultivate it.
Chemicals of this type are very powerful. With their help, all living things growing on the treated territory are eliminated.
Chemicals can be divided by methods of movement in weeds on:
- Contact. They act only in places where the drug is injected, and they do not move inside the grass.
- System. Drugs seep inside, spreading and weed, destroying it from the inside, including the root.
- Combined. Such means destroy the ground part of the plant and its root.
In addition, herbicides can be classified according to the place of impact:
- Anti-Tonic Dicotyled grass is destroyed
- Graminicides. Fighting grass in cereal crops.
How effective are these drugs?
These drugs, effective today in the fight against weeds, depend on specific factors:
- Application Method
- following the instructions for use,
When the product gets on the ground, then under the influence of ultraviolet rays and climatic conditions very quickly loses its toxicity. On average, it loses its properties after 21 days, although each substance decomposes at different rates. Chemicals are best distributed in the first couple of days after application to wet soils, as well as in the rain.
The effectiveness of drugs directly depends on land preparation. The more earthy lumps there are, the worse the remedy will be. In this case, even torrential rains will not save the situation. It is recommended to embed the substances after planting when the soil is still wet. It is better to zaryhlivat them in the upper layer of the earth after processing.
The use of herbicides for plants during the growing season is recommended in warm weather (+18 +21 degrees), windless in the morning when the dew comes down. The most toxic products are in the process of treating young weeds. In this case, the drugs are slower, but have greater resistance to external factors.
How and what herbicides from weeds of selective and continuous action to use, their names
If a gardener wants to get the maximum effect from chemicals, then when using them he must follow certain rules.
1. To use chemicals, having familiarized with the instruction on their use.
2. When choosing a drug, look at the active substance, because many drugs are called differently, but their composition is similar.
3. Timely carry out the treatment of the dacha area in the spring, autumn and summer periods.
4. Do not use chemicals at low night temperatures and high (from 25 degrees) daytime.
5. Exclude the use of herbicide, if the culture has damage and disease.
6. Do not treat with a single chemical. The best would be the use of herbicide turnover, that is, the alternation of substances.
7. Dilute funds only in clean containers.
8. Before processing, it is desirable to moisten the soil well (in advance), but cultural seedlings should remain dry.
9. Be sure to use personal protective equipment when using herbicides.
The use of drugs for certain cultivated plants
To increase the yield of greens and vegetables in the beds, it is necessary to use different chemicals to destroy weeds. If you pick them correctly, you will be able to defeat the weeds in the summer cottage. But, as you understand, all this is temporary, as new (or "sleeping") seeds brought by the wind or birds are already waiting in the wings. Therefore, the fight against weeds goes in a circle.
For main vegetable crops, different chemicals with selective effects can be used.
For this vegetable fit:
- "Butizan". This drug helps to fight dicotyledonous as well as cereal grasses when the seedling cultivation is used. The application rates can be found by reading the instructions on the container with the substance. Planting of seedlings can be made only a few days after cultivating the land with Butizan. For a month re-processing is not carried out, and the seedlings can be tucked only after the end of this period,
- "Treflan". This herbicide is introduced into the ground before planting sprouts, the drug must necessarily be dredged. When selecting a dose, the degree of soil fertility must be taken into consideration. The harder it is, the more it is necessary to take a dose of
- "Semeron". It can be used in the vegetation process of the vegetable to maintain the cleanliness of the beds,
- "Panther". Effective for the elimination of all cereals.
- "Treflan". It can be used before planting sprouts or sowing seeds for 2 weeks. The soil should be preliminary cultivated, since Treflan will be useless in eliminating adult weeds,
- "Zenkor (Ultra)". It is relevant both before planting tomatoes, and in the process of their growing season, when the plant has no more than 4 leaves,
- "Fusilad". Used when grass begins an active period of growth,
- "Stomp 33". It is suitable for the destruction of dicotyledonous cereals, annuals,
- "Targa". With this tool you can spray the grass before the tomatoes have released several leaves.
For her, among other herbicides, fit:
- "Prometrin". This chemical can cope with any cereal plants. The tool has an effect through the foliage and roots of herbs.
This vegetable can be protected from grass by taking advantage of "Treflan". It is allowed to use it before planting sprouts, the drug must be embedded in the soil a few centimeters deep.
Of chemicals you can make:
- "Pyramine". It is allowed to make before the first sprouts appear. It affects the roots and weeds die after germination,
- "Burefen". Eliminates broad-leaved herbs, introduced after the culture has risen,
- "Hexelur". It is very toxic, it fights perfectly with annuals. If it is good to irrigate the soil, then its full decomposition occurs approximately six months after treatment,
- "Betanal". Herbicide eliminates dicotyledonous one-year-olds, after the formation of several sheets on them.
- "Treflan"(introduced after sowing the crop, being embedded in the soil),
For greens you can apply:
- "Gezagard". It is necessary to carry out spraying of crops during the growing season, when the plant has 2 leaves,
- "Stomp". It should be made before shoots appeared.
You can use various chemicals for it:
- "Zencore"It fights annual one-pointed dicots, is introduced before sprouting, as well as when the crop grows 12 cm,
- "Frontier". Cleans ridges of all grass weeds, you can make it before the appearance of the first shoots of the culture,
- "Gezagard". Processing is carried out a couple of days before the appearance of sprouts.
Are universal, destroys all herbs. It is possible to treat the territory with them until the first germs of cultivated plants appear, or by carefully protecting those that have appeared and growing during spraying. The substance does not accumulate in the soil; it affects solely shoots and foliage.
It is the most popular herbicide among gardeners and gardeners. Copes with difficult weeds (a loach, a creeping wheat grass, a thistle and other). "Tornado" kills the plant completely, because it penetrates through the stem into the roots. This remedy is low toxic, however it should be used with caution. "Tornado" can make the entire season when clearing curbs and ditches, and in the fall they are encouraged to spray harmful plants.
According to the spectrum of action
Within each direction of action, herbicides are capable of destroying all plants or only a part of them. On this basis, they are divided into two groups according to the spectrum of action:
- continuous herbicides: detrimental effect on any vegetation, are used in the treatment of the territory of sports fields, irrigation canals, roadsides, etc. (a photo)
- selective herbicides (selective) selectively damage the plants, are used in growing crops. In turn, the degree of selectivity means divided into:
- widely selective (for example, triazine derivatives in corn sowings inhibit the growth of a variety of weeds belonging to both Dicots and Monocots),
- narrowly selective.
Herbicides are divided into:
- aryloxyalkyl carboxylic acids
- carbamic and thiocarbamic acid derivatives
- triazine derivatives
- sulfonylurea derivatives
- derivatives of aryloxypropionic acids
- organophosphate herbicides.
According to the ability to move around the plant
Based on this, herbicides are:
- contact: getting to the surface of the plant, they cause damage at the point of contact (local penetrating action).
- systemic: after being applied to a plant, they penetrate into it and with a current of fluid spread through the organs, causing a general defeat. Such substances are of particular value when the fight occurs with weeds that have developed roots that are difficult to damage by other means.
Herbicide Chemical Classes
Destruction of cell membranes
Bipyridyls, triazolinones, diphenyl ethers.
After absorption by leaf tissue, they form free radicals that have a damaging effect on cell membranes. Reactive oxygen species interact with fatty acid residues, and the reaction of lipid peroxidation starts. The membranes are damaged, the contents of the cells pass into the extracellular space. In the sun, this process is faster. Initially, disintegration occurs, and then necrosis and draining of tissues. Symptoms of damage to these herbicides develop quickly, within a few hours.
Suppression of the formation of amino acids
The preparations in the plant move to the places of maximum activity of metabolism - to the meristem, entering it through the roots and leaves and moving along the phloem and xylem. Sulfonylureas and imidazolinones stop the production of certain amino acids (leucine, isoleucine, valine) in chloroplasts, blocking the enzyme acetolactate synthase.
Производное фосфоновой кислоты глифосат подавляет 5 – енолпирувилшикимат- 3- фосфат синтазу, регулирующую биосинтез тирозина, триптофана и фенилаланина. Other herbicides of this group stop the formation of L-glutamine, but in our country the means with such an action are not used.
The inhibition of the formation of amino acids leads to the fact that plants lack a structural protein, which suppresses the processes of growth and development. Herbicides that inhibit the synthesis of amino acids, act relatively slowly, the effect develops over several days.
Phenoxyacetic, quinolinecarboxylic, benzoic, pyridinecarboxylic acids.
They replace the natural hormones of plants, most effectively manifest their action in dicotyledonous weeds growing in grain crops, because they move little in grain crops. Application is most justified in the initial phases of weed growth.
After absorption through the roots and leaves, hormone-like herbicides have a toxic effect on plants. Features of this action are not known for all herbicides. In some cases, under the influence of drugs initiated the formation of ethylene, which causes growth inhibition in the length of the shoots or roots. At the same time, plant cells increase in size, not having time to store nutrients. This leads to a gradual depletion of the weed and causes death.
Inhibition of fat formation
Cyclohexanediones, benzofurans, aryloxyphenoxypropionates.
Inhibit the formation of fatty acids, have a high degree of selectivity in relation to single and perennial cereals. They process vegetative parts of plants.
They move with a phloem current along the simplast to the places of active growth. As a rule, acetyl-coenzyme-A carboxylase, which is responsible for the initial stages of the formation of fatty acid molecules, is inhibited. Due to the violation of their synthesis, the formation of cell membranes is secondarily inhibited. As a result, plant growth stops almost immediately, and later other symptoms of damage appear, and weed death occurs after 10-14 days.
Triazines, pyridazinones, carbamates, triazinones (systemic), nitriles, thiadiazines (contact).
Block the process of converting solar energy into chemical. As a rule, the most toxic for dicotyledons, sometimes - for cereals. Systemic inhibitors of photosynthesis penetrate the plant through the roots with xylem current and go inside the chloroplast, where they interfere with the work of the electron transport network protein, entering into a chemical reaction with it. Contact drugs are restrictedly moving along the symplast in the shoots. They are also able to block the electron transport chain; moreover, they can uncouple the phosphorylation process during photosynthesis, which leads to the cessation of the accumulation of energy in the form of ATP by cells.
Isoxazolidinones, cyclohexanedions, some fluorine-containing herbicides (flurochloride).
They move more along the xylem, so that they show a better effect when applied to the soil. After penetration into the plant, they are transferred to chloroplast lamellae, where they suppress the formation of chlorophylls and carotenoids, which are necessary for the implementation of the photosynthesis process. Carotenoids transfer light energy to chlorophyll and protect it from photo-oxidation, therefore, if their formation is disturbed, chlorophyll discoloration and loss of its basic properties occur. Suppression of carotenoid synthesis can be done in different ways. For example, fluorochloridone does this by inhibiting the enzyme phytoene desaturase, while benzoylcyclohexanedions inhibit the formation of pigments in the plant, inhibiting the enzyme 4 - hydroxyphenylpyruvate dioxygenase.
Isoxazolidinone clomazone harms the weeds by inhibiting the formation of di- and tetraterpenes (the precursors of gibberellins responsible for the development and growth of plants). Diterpenes are part of chlorophyll molecules, so inhibition of their formation also leads to a decrease in the formation of the latter.
Inhibition of mitosis
Preparations of this class (chloroacetamides, dinitroanilines) inhibit cell division in the meristem, inhibiting the growth of seedlings. In this case, the first group of drugs suppresses the shoots meristem, and the second - the roots. Inhibitors of mitosis are absorbed, respectively, by shoots and roots.
Dinitroanilines inhibit the late stages of the process of mitosis, stopping the formation of the tubulin protein, of which the microtubules that participate in the process of chromosomal divergence during cell division consist. The growth of the roots is delayed as a result, the nutrition of the plants is disturbed, the weeds die. Chloracetamides, apparently, block the formation of long-chain fatty acids, disrupting the formation of new cells during division.