Soap insecticides are based on potassium fatty acids and are used to control many plant pests. Because the insecticide soap works only on direct contact with the pest, the soap is sprayed on the plant in such a way that the whole plant is dampened. Soaps have low mammalian toxicity and are therefore considered safe for use around children and pets and can be used in organic farming.
Video Insecticidal soap
Composition
Insecticide soap should be based on long chain fatty acids (10-18 carbon atoms), because short-chain fatty acids tend to damage plants (phytotoxicity). Short-chain fatty acids (8-carbon) occur for example in coconut oil and palm oil and soap based on the oil. The recommended concentration is usually in the range of 1-2 percent. One manufacturer recommends concentrations of 0.06% to 0.25% (pure soap equivalent) for most agricultural applications; others recommend concentrations equivalent of 0.5 to 1% pure soap. In the EU, fatty acid potassium salts are listed and allowed as insecticides at a concentration of 2%.
Insecticide soap is most effective when dissolved in soft water, because fatty acids in soap tend to precipitate in hard water, thereby reducing effectiveness.
Insecticidal soaps are sold commercially for aphid control. Labels on this product may not always use the word soap, but they will include "fatty acid potassium salt" or "potassium laurate" as the active ingredient. Some types of household soap (not synthetic detergents) are also suitable, but it may be difficult to distinguish the composition and water content of the label. Potassium-based soaps are usually soft or liquid.
Maps Insecticidal soap
Action mechanism
Work mechanism is not understood properly. The possible mechanisms are:
- Soaps, which enter through the insect trachea, can interfere with cell membranes, resulting in the contents of cells that leak from damaged cells (cytolysis).
- Soap can dissolve the wax layer on the cuticle ("skin"), which causes water loss by evaporation.
- Soaps can block the breathing or tracheal opening, which causes drowsiness.
- Soap can interfere with growth hormone.
- Soaps can affect the metabolic insects.
Affected organisms
Insecticide soap works best on soft-bodied insects and arthropods such as aphids, adelgida, white fleas, spider mites, thrips, plant lice jumps, scale insects, whiteflies, and saw larvae. It can also be used for caterpillars and wereng, but these large insects can be more difficult to control with soap alone. Many pollinators and predatory insects such as lady beetles, beetles, and flies are relatively unaffected. However, soap kills predatory mites that can help control spider mites. Also, larvae of insect-eating beetles from female beetles, lacewing, and hoverflies can be negatively affected. According to one study, one soap application kills about 15% of lacewing and lady-beetle larvae, and about 65% of mite predators ( Amblyseius andersoni ).
Green peach aphids are difficult to control because they reproduce rapidly (one adult female can deposit up to four nymphs per day) because they tend to be under the leaves and on the leaf ("armpit leaf"), where they may not be wetted by sprays soap. Manufacturers do claim that their insecticide soap is only suitable for controlling green peach aphids if used in combination with other insecticides, whereas the same soap can control other aphids by itself. Among green peach aphids that are in contact with 2% soap solution, about 95% of adults and 98% of the nymphs die within 48 hours. At a concentration of 0.75%, mortality rates were reduced to 75% and 90%, respectively.
Since 2011, soap insecticides have also been approved in the United States for use against powdery mildew. In European pesticide registrations, its use as a registered insecticide for aphids, whiteflies, and spider mites. At different concentrations, it can also be used against algae and moss.
Use
Insecticide soap solutions will only kill pests during contact; it has no residual action against aphids that come after dry. Therefore, the infested plant must be completely wetted. Repeated application may be necessary to control high pest populations adequately.
Spray soap can damage the plant, especially at higher concentrations or at temperatures above 32 ° C (90 ° F). Plant injuries may not be visible until two days after application. Some plant species are very sensitive to soap sprays. Very sensitive plants include: horse chestnut, Japanese maple ( Acer ), Sorbus aucuparia (mountain ash), Cherimoya fruit, Lamprocapnos (heart bleed ), and sweet pea. Other sensitive plants are, for example: Portulaca , some tomato varieties, Crataegus (hawthorn), cherries, plums,
Damage may occur such as yellow or brown spots on leaves, burning tips, or charred leaves. Plants under pressure of drought, young transplants, cuttings and rootless plants with mild young growth tend to be more sensitive. Sensitivity can be tested on a small plant or plot before a full-scale application.
One manufacturer recommends that the application be done at intervals of 7 to 14 days, with up to three applications, since repeated applications may aggravate phytotoxicity. In addition, the water conditioning agent can improve phytotoxicity.
Thanks to the low mammalian toxicity, soap insecticidal applications are usually allowed until harvest day.
References
See also
- Biological pest control
- Green pesticides
- Insect traps
- Useful grass list
- List of plants that resist pests
- Organic farming
Source of the article : Wikipedia
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