This is known as a fruit surface rust problem, typically caused by a combination of boron deficiency and surface fungal infection.
When the fruit lacks boron, the skin becomes less elastic during development, making the cell walls prone to cracking and oxidation. This results in a rough, rusty, or mottled appearance. In humid or poorly ventilated conditions, pathogens can also invade the weakened skin, worsening the rust-like symptoms.
Recommended Treatment:
Initial Treatment Phase:
Mix 20L water with 50ml Mr Ganick CalMagBo+ + 50ml Mr Ganick Bact-X + 50ml Mr Ganick Moldy Guard + 2 pumps Mr Ganick Silwet. Spray every 5–7 days, for 3 consecutive applications to quickly address both nutrient deficiency and fungal spread.
Follow-up Maintenance Phase:
Once the fruit skin shows clear improvement, reduce the dosage to 30–40ml each of Mr Ganick CalMagBo+, Mr Ganick Bact-X and Mr Ganick Moldy Guard per 20L of water. Spray every 10–14 days, for 2–3 times to maintain and strengthen results.
