The pitaya (also known as pitahaya, dragon fruit, huǒ lóng guǒ (火龍果/火龙果), strawberry pear, nanettikafruit, or thanh long) is the fruit of several cactus species, especially of the genus Hylocereus, but also see Stenocereus. Native to Mexico and Central and South America, these vine-like epiphytic cacti are also cultivated in Southeast Asian countries such as Vietnam, the Philippines, and Malaysia. They are also found in Taiwan, Okinawa, Israel, and southern China. The pitaya blooms only at night; they are large white fragrant flowers, typical of cactus, that are often called Moonflower or Queen of the Night.
The species Stenocereus gummosus in the Sonoran Desert has been an important food source for Native American peoples. The Seri people of northwestern Mexico still harvest the highly appreciated fruit of the pitaya agria (Spanish), which the Seris call ziix is ccapxl - "thing whose fruit is sour".
The plant has adapted to live in dry tropical climates with a moderate amount of rain. The dragonfruit sets on the cactus-like tree 30-50 days after flowering and can sometimes have 5-6 cycles of harvests per year. There are some farms in Vietnam that produce 30 tons of fruit per hectare every year. 
Pests, diseases and problems
Overwatering or excessive rainfall can cause the flowers to drop and fruit to rot. Birds can be a nuisance. There is a bacterium named Xanthomonas campestris, which causes the stem flesh to rot. The fungus Dothiorella can cause brown spots on the fruit, but is not common.
The fruit comes in three types, all with leathery, slightly leafy skin:
- Hylocereus undatus, white flesh with pink skin
- Hylocereus polyrhizus, red flesh with pink skin
- Selenicereus megalanthus, white flesh with yellow skin
The fruit can weigh from 150-600 grams and the flesh, which is eaten raw, is mildly sweet and low in calories. Eating the fruit is sometimes likened to that of the kiwifruit due to a prevalence of sesame seed-sized black crunchy seeds found in the flesh of both fruits which make for a similar texture upon consumption. The skin is not eaten. The fruit may be converted into juice or wine; the flowers can be eaten or steeped as tea. Although the tiny pitaya seeds are eaten with the flesh, the seeds are indigestible. It is generally recommended that dragon fruit be eaten chilled, for improved flavor.
- Felger, Richard; Mary B. Moser. (1985). People of the desert and sea: ethnobotany of the Seri Indians. Tucson: University of Arizona Press.