Insecticide classification - everything from A to Z
Sadly, farmers often have to share their crops with both family members and insect pests. A detailed classification of insecticides will help the grower find the right solution to deal with unwanted guests. These drugs differ from each other in chemical composition, the way the pest enters the body and the degree of danger to humans and animals.
Pesticides are of both selective and continuous action. For example, larvicides are used to kill insect larvae and caterpillars. At the same time, ovicides destroy insect eggs and also kill ticks.
Insecticide classification: 4 mechanisms of action
Either one or several chemical compounds act as part of a special chemical. Upon contact with an insect, the poison causes a certain reaction in the body. As a result, paralysis occurs and the subsequent death of the pest.
Depending on the mechanism of action, means of controlling harmful insects are divided into 4 groups:
- Intestinal. They are applicable to all gnawing parasite species - moths, beetles or butterfly larvae. The poisonous substance begins to act only when it enters the digestive system: mouth, stomach and intestines.
- Contact insecticides. The chemicals are formulated from organophosphates, peritroids or synthetic substances. The poison gets inside through the skin, so the product is simply sprayed over the foliage. It does not cause burns, but it kills thrips and aphids.
- Fumigants (respiratory). The insect inhales the fumes / gases of the insecticide, resulting in paralysis or blockage of the pest's airways. They are used for severe contamination of the area / building.
- Systemic insecticides. In this case, the plant absorbs the chemical and distributes it to all fibers and tissues. Thus, the culture turns into a poison for pests. However, such pesticides act gradually.
Contact drugs have one drawback. After rain, dew or fog, the poisonous mixture is washed off the plants. Therefore, processing is carried out in dry weather.
The given characteristic is relative, because manufacturers often produce drugs with complex effects. Therefore, they are often grouped according to their chemical composition. Particularly popular are insecticides of contact-intestinal action, since they destroy not only one type of pest, but several.
Systemic insecticides are divided into 3 categories, depending on the intended use. Acaricides are used to control ticks, but nematicides and anthelmintics are used against round hearts and parasites.
The chemical composition of insecticides is a rich heritage of world science
Manufacturers can obtain the active ingredient in a variety of ways. They use copper, mercury, sulfur, barium or fluorine as inorganic compounds. Some products are produced on the basis of the waste products of fungal spores, as well as plants or other microorganisms. They include both pretrins and avermectins. However, the use of organic insecticides is a market leader.
These drugs are of 3 types:
- Peritroids. They have a selective effect, therefore they are safe for warm-blooded animals. They penetrate deeply into the cuticle of plants and stay in it for a long time.Due to this feature, they are used at very low temperatures. Sadly, insects quickly get used to them and even develop immunity.
- Organophosphate insecticides (FOS). They have a high initial toxicity (period of activity from 10 to 40 days) and have a neuroparalytic effect. The compounds are capable of rapidly degrading in soil / water into non-toxic products. The consumption of the drug is insignificant.
- Organochlorine. The poisonous compound affects the nervous system, blocking the passage of nerve impulses. Paralysis with subsequent death does not occur immediately, but within a week. COS dissolve well in fatty, oily mixtures, but very poorly in water.
FOS-based preparations have the endings “-thion” and “-phos”. This helps to immediately identify them among the "competitors". However, due to the high toxicity, WHO has banned the use of some organophosphorus compounds.
Also in the classification of insecticides there is another group - neonicotinoids. They are obtained by extracting toxic substances from tinctures. tobacco or makhorka. When they enter the pest's body, they have a paralytic effect on the nervous system, often causing overexcitation. This leads to impaired coordination of movements and respiratory reflex, and also causes convulsions and diarrhea. The drugs are effective in combating gnawing, soil and sucking pests: leafhoppers, aphids, thrips, Colorado potato beetle, nutcracker, weevils and beet crumbs.
Insecticide hazard class - safety first
In addition to the listed funds, manufacturers also produce drugs from biological materials. When creating them, stamps of viruses or bacteria are used. The chemicals have a slow effect on pests, gradually inhibiting basic bodily functions. They pose no danger to plants or humans. At the same time, these funds are not suitable for massive landings. Therefore, experts advise using more toxic substances.
The hazard class of insecticides is determined by their effect on the human body. This takes into account the degree of carcinogenicity and toxicity of the active ingredient, as well as the reaction of the mucous membrane to it.
Basically, 4 groups of such drugs were identified:
- Especially / extremely dangerous (ΙA). These include respiratory toxic chemicals. Such fumigants are used only in closed rooms (without the admission of people), therefore they are not advised to be used in the national economy. Maximum allowable concentration (MPC) - less than 0.1 mg / m³. Durability - 2 years.
- High hazard (ΙB). They are created on the basis of a very toxic substance - fenthion. Therefore, they are prohibited from processing food or forage crops. MPC - 0.1-1 mg / m³. Durability - 6-24 months.
- Moderately hazardous (ΙΙ). These include pyrethrins, which are less toxic to warm-blooded animals, and organophosphate insecticides, which kill cold-blooded animals. MPC - 1-10 mg / m³. Durability - 6-12 months.
- Low hazard (ΙΙΙ). They include avermectin, the decomposition of which occurs within 5-7 days. This is very important when processing fruit and berry lands. MPC - from 10 mg / m³. Longevity up to one month.
Extremely dangerous drugs are used only in exceptional cases, and high-risk drugs are used under the supervision of experienced specialists.
Some of the components of these chemicals can be mutagenic in human cells, tissues and organs. Others affect the fertility of men and women. Poisonous compounds cause irreparable harm to people and the environment. Epidemiological studies have shown that in areas where there is a high load of insecticides (up to 0.7 kg / ha), children are born with congenital malformations.
Features of the use of insecticides - the importance of prudence
Most chemicals are produced in the form of liquid solutions, powders or granules. Sprays and crayons are also produced. Before starting the etching, carefully read the instructions. Manufacturers separately create preparations for the garden, indoor crops and vegetable gardens.
There are 4 methods of using pesticides:
- spraying;
- fumigation - steam and gaseous installations;
- pollination;
- bait in the form of granules, powder.
The last type of insecticide is introduced into the soil during digging or weeding. Liquid concentrates are diluted gradually. A third part is separated from the required volume of liquid. The required amount of the chemical is dissolved in it, mixed, and then the missing amount of water is introduced. Processing is advised to be carried out immediately after preparation. The solution loses its effectiveness within 30-60 minutes.
Household insecticides are used with particular caution, since they have direct contact with humans. May come in contact with skin or respiratory tract.
Properly prepared water will help enhance the effect of the insecticide. Choose a liquid with a neutral or slightly acidic reaction (5.5-7 pH). In alkaline mixtures, the toxic chemical loses its properties. Therefore, some gardeners add a little citric acid (5 g / 10 L) or vinegar (9%, 5 ml / 10 L). The temperature of the liquid should be between 10 and 16 ° C. In cold water, the solubility of the drug decreases by an order of magnitude.
This classification of insecticides will help the gardener find the remedy that will best help him deal with the horde of insect pests.