Raising Kernel Yield in Hazelnut: Casablanca Technology Against Bacterial Disease

Although Türkiye supplies roughly 70% of world hazelnut production, yield per decare and "kernel yield" (the proportion of filled kernels) are still below the desired level. Research by the Ministry of Agriculture and by universities shows that the main causes of this loss are bacterial blight (Xanthomonas arboricola) and blank nuts arising from inadequate nutrition.

Traditional Bordeaux mixture applications are giving way to liquid copper technologies, which the plant takes up far faster and which carry a lower risk of phytotoxicity. In this article we examine the scientific basis and field effects of using Casablanca in hazelnut growing.

1. Why is copper (Cu) important for hazelnut?

Copper plays three critical roles in hazelnut physiology. Where it is deficient, shoot tips die back, leaves deform and · most importantly · fruit drops.

• Lignification and disease resistance: copper is the main component of the enzymes (polyphenol oxidase) responsible for the synthesis of lignin, which forms the cell wall. Hazelnut trees with enough copper have stronger shoots and thicker leaves. That physical barrier makes it harder for bacterial disease to enter.
• Photosynthesis and chlorophyll: copper is involved in electron transfer during photosynthesis. Where it is deficient the leaves fade, photosynthesis slows and the tree cannot produce the energy needed to fill the kernel.
• Pollen health: the copper level during flowering directly affects the success of fertilisation and the proportion of female flowers that convert into fruit.

2. Why liquid, not granular?

Academic studies show that the stomata on the underside of hazelnut leaves absorb nutrients in liquid form 8–10 times faster than granular fertilisers.

• Casablanca technology: because it is fully water soluble it is not washed away by rain and enters the plant sap directly. On steep hazelnut terrain in particular, where soil application is difficult, foliar feeding is a vital alternative.

3. Three core effects in hazelnut

With its specific copper formulation, Casablanca creates visible differences in the hazelnut orchard.

A. The "rubber plant" effect and physical armour

The rubber effect refers to a hardening of the hazelnut leaf and of the husk structure.

• Benefit: hardened tissue makes feeding difficult for pests such as the nut weevil and forms a natural shield against bacterial entry.

B. Higher kernel yield

Casablanca keeps the nutrient conducting bundles (xylem and phloem) healthy, so water and nutrients taken from the soil are carried directly to the kernel.

• Result: the proportion of blank nuts falls, a kernel yield target of 50–52 becomes easier to reach, and a premium quality crop is achieved.

C. Resistance to climatic stress

Late spring frost is the hazelnut grower's greatest fear. Because the cell sap of plants fed with Casablanca is more concentrated, its freezing point falls and the plant becomes more resistant to cold.

4. Application programme for hazelnut

The most critical periods are when leaves reach "mouse-ear" size, the fruit set period and after harvest.

Method	Rate	Timing and frequency
Foliar (sprayer)	1–1.5 litres per 100 litres of water	Before and after flowering and during husk development. 2–3 applications at 15-day intervals.
Soil (drip)	500–750 cl per decare	Before and after flowering and during fruit growth. 2–3 applications at 15-day intervals.

Conclusion

Hazelnut is not merely a crop but a national asset. Correct nutrition is essential to protect that asset and increase its value. With scientifically established copper technology, Casablanca raises disease resistance in your orchard while helping you achieve a high-kernel-yield, high-quality crop.

Remember: we recommend a soil and leaf analysis for the most accurate fertilisation programme.

References and further reading:

1. Lamichhane, J. R., & Varvaro, L. (2014). Xanthomonas arboricola pv. corylina: a complex and emerging pathogen of hazelnut. Plant Pathology.
2. Balık, H. İ., & Beyhan, N. (2018). Blank nut formation in hazelnut and its relation to nutrient elements. Ondokuz Mayıs University, Faculty of Agriculture.
3. Michigan State University Extension. Pros and cons of granular and liquid fertilizers.
4. Casablanca technical brochures. Casablanca Tarım product content and application instructions.
5. Olsen, J. (2013). Hazelnut Bacterial Blight Control Strategies. Oregon State University Extension Service.