PHOSGUARD B-Zn

PHOSGUARD B-Zn is the flowering-stimulation grade, a high-potassium phosphite that carries boron and zinc into the reproductive phase. The potassium load supports the sugar movement that fills and finishes fruit, while boron and zinc work on pollen viability, fertilisation, and the auxin balance behind flower development. Systemic phosphite runs alongside as plant-health support through flowering and early fruit growth. It is positioned for fruiting and flowering crops at the stage where set and finish are decided.

Key Benefits

• Primes the crop’s defence response. Phosphite triggers phytoalexin and phenolic synthesis and cell-wall reinforcement, keeping the plant’s defences active through flowering.
• Supports resilience against oomycete pressure. The phosphite is directly unfavourable to organisms such as Phytophthora and the downy mildews, protecting flowers and young fruit when they are most exposed.
• Stimulates flowering and fruit set. Boron underpins pollen viability and fertilisation, and zinc supports the auxin balance behind flower and shoot development.
• Carries a high potassium load for fruit finish. Potassium drives the sugar translocation and water regulation that size and finish developing fruit.

How It Works

PHOSGUARD B-Zn delivers phosphite, the phosphonate ion, which crops absorb quickly and move systemically through both xylem and phloem after a foliar spray or fertigation application. Inside the plant, phosphite acts in two complementary ways that depend on concentration. At higher local concentrations it is directly unfavourable to oomycete organisms such as Phytophthora, Pythium, and the downy mildews, slowing their growth and energy metabolism. At lower concentrations it primes the crop’s own defence system, triggering the synthesis of phytoalexins and other phenolic compounds, reinforcing cell walls with lignin and suberin, and raising the activity of defence-related enzymes. Because it is fully systemic, the protection reaches new growth and tissues the spray never directly contacted.

This grade leans on a high potassium load carrying boron and zinc, aimed squarely at the reproductive phase. Boron underpins pollen viability and fruit set, zinc supports the auxin balance behind flower and shoot development, and potassium drives the sugar movement that fills and finishes fruit. The phosphite runs alongside as systemic defence support through flowering and early fruit growth.

When to Use PHOSGUARD B-Zn

PHOSGUARD B-Zn is targeted at flowering and early fruit growth, when pollination and set are decided.

• Apply PHOSGUARD B-Zn from pre-flowering to support pollen viability and a strong fruit set.
• Use PHOSGUARD B-Zn through early fruit growth to add a potassium contribution to sizing and finish.
• Include PHOSGUARD B-Zn in foliar or fertigation programmes on fruiting and flowering crops at the reproductive stage.

Plants mount their strongest defences when they are healthy and unstressed; when a crop is under pressure those responses slow, which is exactly when systemic support earns its place. Applying ahead of and through high-pressure periods keeps the crop’s defences primed when it cannot fully prime them on its own.