Japanese citrus crop drought and heat stress

Japanese citrus farmers are struggling with extreme heat and severe water shortages. In the Hidaka region of Wakayama, a lack of rainfall since mid-July has threatened mikan orange yields and fruit size. To mitigate sun-scald, producers in Miyazaki have begun testing ‘White Coat’, a white calcium agent designed to reflect sunlight away from the fruit.

By early September, the drought in Wakayama Prefecture intensified, prompting the establishment of a drought response headquarters for the first time in 21 years. Rainfall in August was recorded at only 10.5 mm, approximately 10 percent of the seasonal average.

The shortage has caused significant damage to the citrus industry, with many mandarin oranges failing to meet shipping standards due to undersized growth. Some fruit is reportedly too small even for juice processing. Additionally, the lack of water is impacting the long-term health of the orchards, with farmers observing leaf curling and noting that up to 40 percent of trees in certain areas have been weakened.