Challenges and Strategies to Mitigate Weather-Related Damage to Premium Citrus

The first part of this year’s citrus campaign has been significantly affected by severe weather events, particularly an isolated low-pressure system (DANA), which primarily impacted the Valencia region of Spain, one of the world’s leading citrus-producing and exporting areas. The heavy rainfall caused by this system led to quality issues in various fruit varieties, resulting in complaints in international markets.

Impact on the Second Half of the Campaign

The consequences of these extreme weather events could persist into the second half of the campaign, especially for varieties that are naturally more susceptible to damage, blemishes, and physiological alterations in the peel.

The impact is even more critical for premium hybrid mandarin varieties—such as 'Tango', 'Nadorcott', 'Leanri', 'Murcott', and 'Orri'—which have high commercial value and require delicate handling. This is particularly concerning because much of this fruit is exported in containers to distant markets, with journeys that can last several weeks.

Blemishes and Alterations: Causes and Evolution

In recent weeks, damage to the fruit has manifested in different patterns of occurrence and intensity, depending on factors such as the specific campaign, harvest timing, production region, or even the individual batch.

These peel defects begin in the field and can evolve over time. Some become visible upon arrival at the warehouse, while others develop during the post-harvest process, whether after treatments in the packing house, during storage, or even at the destination (Cover image).

The causes of these alterations are varied and are still being studied. However, a clear link has been observed between the damage and adverse weather conditions, such as waterlogging followed by sudden dehydration of the trees.

The current situation, characterized by fields in the Valencia region impacted by these weather extremes and unusually high winter temperatures, could accelerate the ripening of the fruit and lead to premature aging of the peel, making it more susceptible to damage such as cold spots or blemishes caused by prolonged storage (Orihuel-Iranzo et al., 2018).

Strategies to Minimize Post-Harvest Damage

In response to these challenges, it is crucial to adopt strategies that reduce the impact of blemishes on sensitive varieties, both in the field and during the post-harvest process. Below are some key measures:

• Careful Harvesting: Select fruits that have not been exposed to sudden temperature changes or external damage. It is recommended to avoid exporting fruit from orchards with a history of quality problems, areas prone to prolonged waterlogging, or fruit harvested immediately after heavy rainfall.

• Rigorous Sorting in the Packinghouse: Increase sorting efforts to remove fruit with visible defects, ensuring greater consistency and higher quality in the final product.

• Application of Phytoprotectants: Use CitroProtect Plus with a drencher, basin, or online drencher treatment to reduce the incidence of blemishing. This product protects the citrus peel and reduces the occurrence of damage and physiological disorders, being particularly effective against blemishes caused by storage.

• Proper Waxing: Select the most appropriate coating based on the destination of the fruit, which helps minimize cold damage and improves the preservation of fruit during transport. Available options include SunSeal, SunSeal Vegan, and PlantSeal.

Implementing these strategies correctly will help mitigate the impact of extreme weather on fruit quality, ensuring that premium varieties retain their commercial value and remain accepted in international markets.

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Source

Orihuel-Iranzo B., Navarro I., Bretó J., Mottura M.C. 2018. Characterization and control of bottom box water spot, a new citrus rind disorder in Spain. Acta Hortic. 1194. ISHS 2018.

Cover Image

Evolution of blemishing on a Tango mandarin fruit treated, packed, and stored for 7 days, followed by 0 and 3 days at room temperature.