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What is Potassium Phosphite?

Potassium Phosphite (Potassium Salt of Phosphorous Acid/ Potassium Phosphonate) is a innovative fungi static formulation systemic in action based on the group of potassium phosphite which enables plant to overcome several fungal infections by enhancing natural immune system.

It is absorbed by plants and incorporated into cells as phosphite ions. Theses phosphite ions have direct antifungal effect on plant pathogens. These ions are very much effective in controlling diseases caused by group of fungi known as oomycetes including phytophthora. Plasmopara, Pythium and other fungi.

When applied as foliar or soil drench can translocate in both phloem and xylem which allows it to control root born diseases. Potassium phosphite is non phytotoxic and having very minimal pathogen resistance hence can be used in organic farming. It can be used for both protective as well as curative treatment.

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Potassium phosphite has a white-powdery appearance and a molecular formula of H2KO3P. In addition to its solubility in both water and ethanol, the compound is also used to form foliar fertilizer and as a fungicide.

Phosphorous acid (H3PO3) is neutralized with KOH, it forms the salt of Phosphorous acid, potassium phosphite (KH2PO3) to form Potassium Phosphonate. Also Phosphorous acid reacts with Potassium carbonate to give Potassium phosphonate. H3PO3+KOH→KH2PO3+H2O Or 2H3PO3+K2CO3→2KH2PO3+CO2+H2O

Mode of Action in Plant –

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Potassium Phosphonates are systematically absorbed by the plant and are mobile, within the plant, trans-locating to the new growth, via both the phloem element and the xylem. They are a highly soluble form of Phosphorus and Potassium, which is beneficial to plant growth, rooting and root development, accelerating foliar uptake of other cations such as potassium, calcium, magnesium, and most micro elements. Not only does phosphite help roots, but is actually beneficial to the regeneration of mycorrhizae on the roots of trees. Phosphorus and Potassium, are rapidly absorbed by the leaf tissue and roots for maximum and efficient plant use by moving systemically upward and downward in the plants vascular system, phloem and including the root system.

Once applied and rapidly absorbed, by the plant, phosphites undergo an oxidation or conversion process resulting in the continual release of soluble phosphorus. The phosphonates have been observed to activate defense mechanisms that kick into gear when attached by disease or insects. This product has fungistatic activity against major fungal pathogens and has shown to promote the trees natural defense systems capable of stimulating host defenses through induced systemic resistance. The mode of action of phosphorous acid is twofold, by acting first within the fungus, inhibiting fungus growth, and also by changing the nature of the fungal cell walls by activating the plants own immune defense response through rapid cytological action, and triggering other cellular phytoalexin accumulations and metabolic changes and other resistance inducers. Phosphonates are highly selective, non-toxic fungicides against numerous fungal pathogens, and provide both protective and curative responses against such plant diseases. It is a highly systemic sterol inhibitor that penetrates and Trans-locates, preventing fungal cell development, by interfering with cell wall formation and growth throughout the plant by inhibiting sterol biosynthesis. Once the phosphite moves up the tree and enters the leaves, it stimulates the production of infection-fighting chemicals within a layer known as the cambium. Phosphites are quickly absorbed by plants; therefore, they present a high degree of solubility and mobility. The systemic character (ascending and descending) and quick absorption by the roots, stems and leaves, allow various methods of application in accordance with the type of plant and characteristics of the pathogen to be controlled. The Phosphite is highly mobile in trees and moves bi-directional in the phloem and upward to the leaves in the vascular systems. Because Phosphite has one less oxygen molecule than phosphate, a higher degree of solubility and mobility, within the plant is achieved. This unique characteristic permits phosphites to be rapidly absorbed or taken up across the membranes of plant foliage and/or roots, in both their nutritive and plant protective roles, with immediate activity on contact. The efficiency of phosphite application in certain pathosystems is due to the fact that the plant presents better assimilation in the presence of phosphorus, making it capable of activating defense.

Potassium phosphite moves through the plant fast, both by basipetal and acropetal transport. It stops mycelium growth and indirectly stimulates the resistance of plants because phosphite encourages the production ofelicitin, which increases immunity.

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Phosphates vs. Phosphite

Many of us are familiar with MAP and DAP (mono and di- ammonium phosphate) and possibly even MKP (monopotassium phosphate) all of which provide phosphorous derived from phosphoric acid (H3PO4). Plants use phosphate in the form of HPO4 and H2PO4 which once applied to the soil is rapidly converted from fertilizers. Phosphite is completely different in nature from phosphate. Chemically phosphate and phosphite are similar, however phosphate has one more oxygen than phosphite and this markedly changes the nature and reactivity of the resultant molecule. These three oxygen molecules give phosphite formulations increased mobility in plant tissue and soils so that they can be successfully applied to all areas of the plant. The recognized, traditional source of phosphorus, as H3PO4, has long been phosphoric acid, and forms a salt when neutralized with a base. The salt is referred to as phosphite, H3PO3, as opposed to the phosphate H3PO4.

Application Rate: 2 to 3 gm per Liter of water for Spraying and 3 to 4 gm per liter of water for soil Drenching.

Compatibility: Compatible with almost all pesticides and fungicides.

Useful Against: Effective on all crops, Fruits and Vegetables (Grapes, Pomogranate,Wheat, Coffee, Black Pepper, Cotton, Rice,Orange, sugarcane, Tea, Coffee, Oil seed, Beans, Ginger, Onions, Papaya, Tomato and Potato,Strawbery,Apple,Turmeric,Cucumber,Capsicum ) and Grasses.

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Advantages of Potassium Phosphite Use

  • Easily absorbed by the plant both through the roots and the leaves
  • Applicable for all types of crops, plants
  • Activates defense mechanism of plant
  • Absorbed and taken up across the membranes of plant foliage, roots in both their nutritive and plant protective role
  • Shows immediate activity
  • Disrupts the phosphorus metabolism in the pathogen, inhibiting its growth and causing it to release stress molecules
  • Photoalexin is produced which attacks the disease directly, phosphite also helps maximize this by providing ideal nutrition.
  • Relieves ‘hidden phosphorus hunger’ during fast growth stages.
  • Stimulates healthy growth during conditions which may be favorable to the development of some root rots and leaf mildew.
  • Complements the action and mobility of other nutrients such as manganese and iron.
  • Non persistent in the environment, as readily oxidized to phosphate by soil microbes, and also has very low mammalian toxicity.
  • Potassium phosphite is non phytotoxic and having very minimal pathogen resistance
  • Compatible with almost all pesticides and fungicides
  • Can be used for both protective as well as curative treatment.
  • Do not remain as harmful residue in plant systemically and locally.
  • Encourages the production of polysaccharides which strengthen the cell walls, giving additional protection.
  • It is more environmentally safer and more target friendly than applying as a foliar spray
  • Increases crop yield remarkably