Casestudy: Protecting Walnuts against heat stress
Isparta, Turkey – August 2024
Walnut growers know the challenge: when summer temperatures rise above 35–40 °C, nuts and leaves are at risk of sunburn, and trees struggle to stay productive. Heat stress doesn’t just damage the appearance of the nuts – it reduces kernel fill, lowers quality, and can cut into marketable yields. That’s why we put Cropshader Orchard, our starch-based, biodegradable shading coating, to the test in a Chandler walnut orchard in Isparta, Turkey.
What We Tested
Two complementary studies were carried out:
- Surface temperature benchmark (fruit and leaf temperatures)
- Photosynthetic activity benchmark (electron transport rate, ETR) using Sendot Research B.V. optical sensors
Application area: 1,000 m² of orchard was sprayed with Cropshader Orchard, while 2 hectares were left untreated for comparison.
Application method: Standard field sprayer at a 1:20 dilution.
Conditions: 37.7 °C with low humidity – tough conditions for walnut trees.
Application of Cropshader in the field: a fine mist evenly covers the trees to protect them from extreme heat.
Fruits coated with a protective white layer that reflects solar radiation and reduces heat stress.
What We Found
- Lower Nut and Leaf Temperatures
On average, treated walnuts and leaves were up to 5 °C cooler than those on untreated trees. This reduction is critical to prevent sunburn and protect nut quality under extreme heat.
- Trees Stayed Active During the Heat
Untreated trees showed stress shutdown in the hottest hours, but coated trees kept photosynthesizing. In other words, they stayed productive when it mattered most — supporting kernel fill and yield stability.
What It Means for Walnut Growers
With sunburn causing up to 30% crop losses in hot years, having a reliable, sprayable protection is essential. Cropshader Orchard gives growers a practical tool to:
✔ Protect nuts from sunburn and shriveling
✔ Maintain tree productivity during heat waves
✔ Improve kernel quality and overall yield stability
✔ Avoid expensive infrastructure like shade nets
And because Cropshader Orchard is biodegradable, starch-based, and EU-certified as a plant biostimulant, it’s both grower-friendly and market-ready.
Takeaway
The Isparta field trial shows that Cropshader Orchard makes a real difference in walnut orchards under heat stress. By protecting nuts and keeping trees productive through extreme summer conditions, it helps growers secure more high-quality yield — exactly when it matters most.