Relatively cool weather and clear water around the Azumino region are suited for growing wasabi, Japanese horseradish (Eutrema japonicum). The largest wasabi farm in the world, Daio Wasabi Farm, is located here in Azumino. Wasabi is originally grown wildly in the streams of the mountains. Therefore, wasabi plants are rather sensitive to the direct sunlight in the fields. Black shade nets are used to cover the wasabi fields to protect the roots and stems of wasabi plants from the heat of the sunlight during summer, from May to the beginning of October. They help to keep the temperature of the running water below 15°C. (https://www.azumino-e-tabi.net/en/sightseeing/daio-wasabi-farm) (https://www.daiowasabi.co.jp/facility/)
Daio Wasabi Farm, Azumino, Nagano, 6/12/2021
There is a pond where rainbow trout (Oncorhynchus mykiss) are raised in the Farm. Yellow orange fish are albino fish, the mutant of the wild type rainbow trout. Adult fish of rainbow trout are distinguished by a broad reddish stripe along the lateral line, from gills to the tail. You can see the reddish stripe on the belly even on the albino type.
Wasabi Stem or Rhizome, the Major Part of the Plant Eaten, Commonly Served Grated; Its Pungent Compound is Allyl Isothiocyanate Produced by Grating the Plant. In Horseradish, the Root is Eaten. Both are Hot and Tangy; but the Japanese Wasabi is Much More Intense with Mild Sweetness. Daio Wasabi Farm, Azumino, Nagano, 6/12/2021 (https://en.wikipedia.org/wiki/Wasabi) (https://foodal.com/knowledge/herbs-spices/horseradish-wasabi/)
HOTAKA RIVER WASABI FIELDS
Other than Daio Wasabi Farm, there are wasabi fields along the Hotaka River in the Azumino area.