In ancient times, the “sun flower” was cultivated by the Indians; now the annual sunflower is planted wherever it takes root. Oilseed seeds germinate slowly, the seedlings are quickly drowned out by weeds, which are simply impossible to weed out by hand over large areas. Before sunflower sprouts appear, the soil is treated with herbicides. Chemicals are sprayed over plantings and during flowering. The drugs not only kill weeds, but also prevent the development of diseases in plants.
Types of herbicides
Sunflower cultivation technology involves the use of 4 types of pesticides, each of which is required at a certain stage.
Pre-emergence
Oilseed seeds germinate not in 3 or 5 days, but in 2 weeks. At this stage of development, sunflowers require a lot of moisture and nutrients, which are taken away by weeds. If the grass is not destroyed early, there will be insufficient reserves in the ground for crop development, which subsequently leads to a decrease in productivity.
To control cereal annuals and dicotyledonous grasses before emergence, contact herbicides are added to the top layer of soil along with the seeds. One of these drugs, “Harnes,” penetrates the tissues of weeds, suppresses growth, disrupts metabolism in cells, and allows sunflowers to develop.
“Pioneer 900” is used to prepare a concentrated solution, which is used to spray the field before the seeds sprout. The ground is harrowed so that the substance gets into the deep layers of the soil, destroys acorn grass, chamomile, and shepherd's purse and decomposes.
Post-emergence
If herbicides were not applied to the soil along with the seeds, when three or four leaves appear, chemicals are sprayed onto the sunflowers that inhibit the production of amino acids in the weeds.
The drugs are marketed in the form of emulsions or granules dissolved in water.
Post-emergence herbicides act only on weeds; they contain several active components:
- Metolachlor is not dangerous for insects, but destroys purslane and chamomile.
- Imazethapyr controls broomrape.
- Terbuthylazine inhibits ragweed but is not toxic to bees and bumblebees.
- Tribenurol-methyl kills hundreds of species of broad-leaved weeds, removes poppies, radishes, and can be used together with fungicides.
The use of desiccants allows you to speed up the ripening of sunflower seeds. The chemical agent “Samum 150” is absorbed by stems and leaves, prevents the development of rot, and destroys weeds.
The best preparations for sunflower
Starting in the fall, the field is treated with herbicides that contain glyphosate. The substance penetrates the cells, destroys the root, and clears the area of sedge and bittergrass. Selective preparations are used when the weed produces at least 2 leaves. Such products kill individual plants, but do not affect neighboring crops.
"Gesagard"
The selective drug has a destructive effect on weeds and protects sunflower plantings for a long time. When spraying the herbicide "Gezagard", the prometrin contained in its composition is absorbed by the leaves and absorbed by the roots, which leads to the death of dicotyledonous grasses and cereal annuals. The pesticide decomposes in the ground, is not addictive to weeds, and is safe for insects and people.
Sunflower is sprayed with “Gezard” once a season along with sowing, 200 liters of solution are consumed per hectare. In arid regions, the herbicide is embedded in the ground to a depth of 30 mm.
"Gambit"
Based on prometrin, a drug is produced in the form of a concentrated suspension, which penetrates through the soil into the seedlings and roots of weeds. Herbicide "Gambit" disrupts the production of amino acids in plants and suppresses photosynthesis. Sunflower protects for 2.5 months:
- from field violets and wild oats;
- shepherd's purse and bluegrass;
- from wild radish and agaric;
- from nettle and dope.
Weeds die in 5–7 days. To avoid the development of resistance, the drug is alternated with other pesticides.The product is sold in canisters of 10 and 5 liters.
"Dual-Gold"
A selective herbicide, which belongs to the class of chloroacetamides, protects plantings of industrial crops from weeds. A drug with a high concentration of C-metolachlor prevents seed germination. "Dual-Gold" reduces the production of enzymes, which leads to a decrease in the rate of cell division and the death of perennial weeds.
The herbicide is buried 20 mm into the wet soil, the above-ground part of the plants is sprayed, after which the area is not treated for up to 2 weeks. The product is not addictive and does not have a negative effect on the soil structure.
"Octopus Extra"
One of the latest developments by scientists kills all representatives of the flora, sprouted herbs die forever. The leaves and stems are sprayed with a systemic herbicide, from where the product, moving through the tissues of the weed, enters the cells of the root system. Plants stop absorbing nutrients and wither. “Sprut Extra” copes with perennials and cereals, which are not affected by many drugs, and is suitable for pre-sowing treatment of sunflower.
"Target Hyper"
The domestic herbicide, which is used to kill weeds in fields after germination, acts selectively and does not harm agricultural crops. "Targer Hyper" is produced in the form of a concentrated emulsion, it is used sparingly, but it destroys the above-ground part and roots of weeds.
"Tornado-500"
To control weeds, sunflower farmers buy herbicides in large quantities. It is profitable to purchase chemicals not in small bottles, but in 5 or 10 liter canisters. “Tornado-500” is packaged in such packaging.The drug contains glyphosate salt in high concentration; when sprayed on weeds, it disrupts the production and absorption of substances.
Sticky additives that are added to the emulsion protect it from being washed away by precipitation. After processing the plants, the composition decomposes in the ground into individual components that are not harmful to the environment.
"Total-360"
The drug containing glyphosate salt copes with all types of weeds, works in hot and cold weather. The active component of the herbicide, penetrating into the weed tissue, destroys the cellular structures, which leads to the death of the roots.
The treatment of sunflower fields with Total-360 is carried out a few days before sowing a season in order to destroy thistle and thistle, wheatgrass and wild oats, bindweed and cereals. When planting industrial crops, the drug is used as a desiccant.
"Fuselad Forte"
The post-emergence herbicide developed by Syngenta does not harm sunflowers, but is dangerous for wheat, rye, and oats. Fusilade Forte is used to treat fields at different stages of development of industrial crops and is effective at temperatures not lower than 10 °C. After spraying, the weeds dry out within a week.
Which weed killer is better to choose?
Before the sprouts emerge, it is recommended to treat sunflower fields with contact-acting preparations that destroy the metabolism in weed cells. Based on feedback from farmers, at this stage of crop development it is better to use:
- "Dual Gold";
- "Pioneer-900";
- "Nitran";
- "Harnes".
When leaves appear on the stems of sunflowers, it is necessary to spray selective herbicides that destroy different types of weeds, but do not affect industrial crops.
The most effective means of blocking the re-growth of weeds include Fusilade Super, Gesagard, Bekkard 125.
General rules for the use of herbicides for sunflower
Before choosing a preparation for treating oilseed crops, you need to find out what types of weeds are attacking the area. Soil-based herbicides are better suited for killing annual grass.
It is necessary to spray the compositions over the above-ground parts of the weeds in the morning or afternoon, but not in the heat, since the substances will be less absorbed by the green mass and stems. When spraying weeds, you must ensure that the solution does not get on the sunflowers. Fields should not be treated with herbicides in windy weather.
The concentration of the drug must be selected in accordance with the annotation, but also take into account:
- soil type and acidity;
- soil moisture level;
- amount of added organic matter.
Timely protection from weeds, as well as compliance with agricultural technology requirements, guarantees high sunflower yields.
