Caterpillar fungus -- known as Himalayan Viagra -- is prized in traditional medicine . Thousands of people travel to Nepal 's Dolpa Valley each year to harvest the caterpillar fungus . Some locals say the harvesters are using forests and grasslands . Expert says education is needed for the harvesting to be sustainable long term .
Caterpillar fungus -- known as Himalayan Viagra -- is prized in traditional medicine . Thousands of people travel to Nepal 's Dolpa district each year to harvest the caterpillar fungus . Some locals say the harvesters are damaging hillsides and grasslands . Expert says education is needed for the harvesting to be sustainable long term .