Ahead of the mango season, the Indian Institute of Horticultural Research (IIHR) under the Indian Council of Agricultural Research (ICAR), has introduced a low-cost technology that removes the black stains many mangoes develop on their skin, marks that make good fruits look spoiled and fetch lower prices in the market.
The solution, which is called Arka Mango Wash, costs about ₹1 per kg of fruit and can be used even by small farmers with simple equipment.
Every year, mango growers across the country face the problem of fruits turning black on the surface, even when the pulp inside remains completely healthy. “These stains are usually caused by sooty blotch, a fungal complex that grows on the waxy layer of the fruit peel. The fungus does not penetrate the fruit; instead, it sits like a thin, olive-green black film that spreads over the skin. It is often confused with another kind of stain called sooty mould, which forms sugary excretions left by sap-sucking insects such as hoppers, where one needs to focus on sucking pest management,” Dr. G. Sangeetha, principal scientist (Plant Pathology), Division of Crop Protection at ICAR-IIHR, said. Dr. Sangeetha developed the technology, alongside co-developer H.S. Singh.
Though the stains due to sooty blotch are only superficial, they severely affect market value because both traders and consumers tend to avoid blemished fruits. As a result, good mangoes get downgraded or sold cheaply, leading to considerable losses.
To address this, IIHR developed Arka Mango Wash, a post-harvest dip treatment that removes up to 99% of the blackening caused by sooty blotch.
How it works
The solution uses a combination of two FSSAI-approved compounds, blended in precise proportions, making it safe for use on fruits. Farmers preparing the wash must mix 250 ml of Solution A (4%) and 9 ml of Solution B (85%) in 10 litres of potable water and adjust the pH to 6.5. Mangoes are dipped for 10–15 minutes, then rinsed twice with clean water and left to dry in the shade before ripening, Dr. Sangeetha, speaking to The Hindu, explained.
Dr. Sangeetha emphasised that potable (non-hard) water is essential because hard water reduces the wash’s effectiveness. The same batch of solution can be reused three to four times, making the process affordable. She also warns that higher concentrations should not be used, as they may cause phytotoxicity or surface injury. When used correctly, the wash leaves no chemical residue and does not damage the fruit.
The technology has been commercialised by IIHR and can be used for cleaning fruits affected by similar fungal blotches, like wood apple. For farmers who lose income due to appearance-related downgrading, the institute expects this wash to significantly improve returns, she said.
Impact on ground
Dr. Sangeetha shared an example from Tamil Nadu that showed its impact on the ground. R. Sadesh Kumar, an organic mango grower from Andikuzhi village in Kallakurichi district, saw large portions of his harvest develop black patches soon after picking. Though his fruits, known for their aroma and taste, were internally perfect, customers rejected them because of the blemishes. His popular direct-sales model in his own petrol station took an immediate hit.
He first tried washing the mangoes with soap water, but the stains remained. He then remembered seeing a demonstration of Arka Mango Wash at an IIHR horticulture fair. Carrying samples of his stained fruits and even farm water for testing, he travelled to the institute in Bengaluru. There, scientists used the mango wash on his samples, restoring their natural shine, she added.
Published – November 25, 2025 07:02 pm IST
