QUELAFERT® FOS-K is a formulation rich in phosphorus and potassium, with phosphorus in the form of phosphite.
QUELAFERT® FOS-K increases defenses against fungal attacks, especially Oomycetes (mildew), and also has an effect on Phytophthora and parasitic Ph, which are responsible for neck rot, water rot, gummosis, etc.
| Format | Units/Packaging | Palet (L) |
|---|---|---|
| 1 L | 12 | 720 L |
| 5 L | 4 | 800 L |
| P2O5 (Phosphoric anhydride) soluble in water, derived from phosphite | 30,00% |
| K2O (Potassium Oxide) soluble in water | 20,00% |
| CROP | DOSAGE |
|---|---|
| Horticulture | 3 cc/L from flowering to fruiting |
| Fruit trees | 3 cc/L in pre-flowering and fruiting |
| Citrus fruit | 5 L/ha in April, July and September |
| Ornamental | 5 cc/L for prevention of neck diseases |
| Potato | 2-3 cc/L to prevent foliar mildew |
Product available in countries where its components are authorized.
Product not authorized in Spain.
QUELAFERT® FOS-K is a liquid fertilizer with fungistatic action, formulated with soluble phosphorus (30% P₂O₅) and potassium (20% K₂O). Thanks to its content of potassium phosphite, this product offers dual functionality: on one hand, it acts as a source of essential nutrients during key stages of crop development; on the other, it effectively prevents diseases caused by oomycetes, such as damping-off and root rot.
With a slightly acidic pH between 3.5 and 4.5 and a density of 1.45 g/cc, it provides excellent stability and compatibility with numerous agricultural products. It can be applied both as a foliar spray and through fertigation, adapting to the demands of intensive, horticultural, and fruit crops.
The use of QUELAFERT® FOS-K strengthens plant structure and stimulates root development, improving water and nutrient uptake during critical stages such as flowering, fruit set, fruit filling, and ripening. As a potassium phosphite fungicide, its preventive action against fungal diseases helps reduce the use of conventional fungicides, promoting a sustainable, zero-residue agricultural model.
Moreover, its versatility makes it a strategic tool in advanced nutrition programs, increasing crop yield and quality without compromising plant health or ecosystem balance. Its formulation as a potassium phosphonate fungicide ensures effective protection while supporting sustainable farming practices.
No. Although it has fungistatic action, QUELAFERT® FOS-K does not contain conventional pesticides or aggressive chemicals. Its effect is based on potassium phosphite, which stimulates the plant’s natural defenses against pathogens.
It should be applied during stages when the crop requires higher phosphorus and potassium intake, such as initial root development, flowering, fruit set, fruit filling, and ripening. Frequency may vary between 2 and 6 applications per cycle, with intervals of 15 to 30 days depending on the crop type.
Yes, its sustained use is safe and beneficial. As a potassium phosphonate fungicide, it generates no toxic residues and can be applied across multiple stages of the crop cycle, helping to maintain the plant’s immune response active without causing physiological imbalances.
Yes. It is a product that respects beneficial fauna and insects, as it does not act as an insecticide or alter the crop’s microbiota. Its mode of action is indirect and safe for the agricultural ecosystem.
Mixing with mineral oils, sulfur, and alkaline-reacting products should be avoided. It is also important not to apply it together with copper-based products. If copper has been used previously, it is recommended to wait at least 15 days before applying FOS-K.
