Strawberry leaf extract shows potential as an organic post-harvest citrus treatment

With production costs rising across the board and demand for clean foods growing, organic and sustainable inputs made from agricultural waste could be a solution benefiting citrus growers and consumers alike. 

In that vein, a team of researchers in Tucuman, Argentina, found that strawberry leaf aqueous extract (SLE) is an efficient post-harvest treatment against citrus fungal diseases, such as sour rot and green and blue mold.

“Regions with warm, humid climates, such as Tucuman, offer optimal conditions for the proliferation of these fungi,” the authors wrote in their 2026 study. “This region generates approximately 80 percent of Argentina’s lemon production, positioning it as a leading global producer.”

Image via Shutterstock

These pathogens cause significant crop losses across the citrus category, and some strains have developed resistance to conventional fungicides such as mazalil, thiabendazole, and pyrimethanil. 

The authors emphasized the importance of finding alternatives to these chemicals, as their intensive use further drives the development of resistant pathogens and “also generates serious adverse impacts on human health and ecosystems.”

How to SLE citrus fungi

Along with citrus, northwest Argentina, where Tucuman is, is also fertile ground for strawberry cultivation, accounting for 50 percent of national production. 

The authors saw a promising strategy in exploring how these two industries could benefit each other, especially given the well-documented ability of different strawberry extracts to protect plants against infections by enhancing plant immunity. This led them to SLE, a simple, sustainable solution made from dried organic strawberry leaves and distilled water. 

The researchers used the compound in assays of both sensitive and resistant strains of the aforementioned pathogens on agar plates. They found that at a concentration of 0.05 grams per milliliter, SLE inhibited fungal thread growth within five days, while at 0.1 grams per milliliter, it stopped fungal growth completely. 

In practical experiments, the authors used SLE on lemons affected by green mold, and the compound showed a 52 percent reduction in disease incidence. 

The study’s results offer an effective and efficient approach to post-harvest treatment of citrus diseases, but also an efficient way of using the over 6,000 kilos of fresh leaf material per hectare that the Argentinian strawberry industry usually discards per season, 

“The production process involves relatively low costs, as it mainly requires logistics, appropriate storage of the leaves, and basic extraction equipment, making it an economically feasible strategy that adds value to the production system while contributing to waste reduction,” the authors noted. 

Image via Shutterstock

Further research is still needed to optimize the compound’s formulation and field application, but the results are promising and a win-win for the entire value chain. 

“The integration of SLE into postharvest protocols could substantially decrease reliance on synthetic fungicides, facilitating a transition toward safer, more efficient systems that align with global food security standards and environmental sustainability regulations,” the authors concluded. 

*All images are referential via Shutterstock. 

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