Insecticidal substances belong to different chemical classes. Among them, a group of pyrethroids stands out. Let's consider the general characteristics and classification of substances, the principle of their operation, the most common drugs from this group, and the rules for using them. Precautions to be observed when working, toxicity and signs of poisoning.
General characteristics of pyrethroids
Natural pyrethroids are found in Dalmatian chamomile flowers, which is why this plant has long been used as an insecticide.The substances that are included in modern insecticides are obtained artificially. Like natural pyrethroids, they act on plant and stock pests, household pests, and animal parasites.
Pyrethroids have a selective effect; their solutions are well retained on the foliage and can partially penetrate into the middle.
Classification
Synthetic pyrethroids are divided into 3 groups (generations). The 1st group includes esters of chrysanthemum acid. The substances are highly effective, but under ultraviolet radiation they quickly oxidize, so preparations with them must be used indoors. Esters are used to combat household insects; they are part of plates and spirals, and aerosols.
The 2nd generation includes substances that are more resistant to oxidation in light. These substances are permethrin, cypermethrin, deltamethrin and fenvalerate. They are effective in small doses; pyrethroid preparations with active substances of this generation are used in agriculture to treat crops against pests. They are also used against household insects, and on fabrics and containers. The disadvantages of 2nd generation pyrethroids are that they are toxic to bees and fish, do not work against soil pests, and do not have a systemic effect.
Substances of the 3rd generation are photostable, minimally volatile, have a long residual effect, less toxicity, some can act against ticks. This group includes cyhalothrin, imiprotrin, bifenthrin, fluvalinate, fenpropathrin.
Principle of operation
Pyrethroids are substances with contact and intestinal effects; they quickly penetrate the chitin of insects. They act on the central nervous system, first causing its overexcitation, then paralysis and death of pests.
The substances compare favorably with insecticidal compounds of other classes in that they can act in cool weather, so they can be used in early spring and late autumn.
Unlike FOS and carbamates, pyrethroid substances do not act on pests that live secretly; they are used primarily against leaf-eating species. The protection effect lasts 2-3 weeks, the waiting time before harvesting the fruit usually takes 3-4 weeks. If pyrethroids are used for a long time, insects can become resistant to them, as well as to other insecticides.
To prevent resistance, it is necessary to alternate treatments with drugs from different groups; if the pyrethroids have a weaker effect, replace them with FOS, products with neonicatinoids, carbamates or other active ingredients.
Most common drugs
Cypermethrin is included in the following products: “Arrivo”, “Superkill”, “Cirax”, “Rangoli-Noril”, “Cyperus”, “Citox”, “Shaman”, “Iskra”, “Inta-Vir”, “Molniya Extra” , "Carbotsin".
Bifenthrin is contained in the insecticides “Prokrop”, “Talstar”, “Vulcan”, “Clipper”, “Zernospas”, “Imidalit”, “Pirinex Super”.
Deltamethrin is part of the drugs “Decis Expert”, “Atom”, “Proteus”, “Biorin”, “Decis Profi”, “Legion”.
Permethrin includes the drugs "Medilis-I", "Medifox-Super", "Acromed-U", "Avicin".
General rules of use
Pest control agents are available in different formulations. Sprays are used in finished form; a solution is prepared from powder, granules, or concentrated liquid. Products with pyrethroids have a small amount and consumption. They can be used in the garden and vegetable garden all season long, and in everyday life - when pests appear. Number of treatments – from 1 time, repeat if necessary.
Precautionary measures
Insecticides with pyrethroids belong to toxicity classes 2 and 3 for humans and to classes 1, 2, 3 for bees and fish. To work with them, you should always wear gloves, goggles, a respirator and protective clothing that covers your body from splashes of the solution. Spray the plants in calm, dry weather. If the solution gets on your skin, wash it off with water; if it gets into your eyes, rinse them immediately with water.
Symptoms of poisoning
The active substances of pyrethroid insecticides can enter the body through the gastrointestinal tract, skin (even intact skin) and through the respiratory tract. They enter fatty tissues and the brain, from where they are excreted over time.
If signs of poisoning with pyrethroid drugs appear, you must, first of all, immediately stop working, then perform gastric lavage at home with a large amount of water with activated carbon. If the condition is serious, you should immediately seek help from a doctor.
Pyrethroids are one of the main insecticides used in agriculture and everyday life. They include substances of various structures that can fight against harmful insects. They destroy many types of insects that parasitize plants and animals, and some types of mites.
