Changes

*''Pyrus serotina'' Rehder (1915), *''Pyrus sinensis'' auct. mult. (non Poiret 1816, nec Lindley 1826).

*Oriental pear, nashi, sand pear (En). *Poire orientale, nashi (Fr)

*Vietnam: lê.  All names, except nashi, refer to other Asian ''Pyrus'' species as well. In this text "nashi" is used for the modern high quality pears grown under intensive cultivation; "sand pear" for the hardy traditional types with gritty flesh; and "oriental pear" is used more generally and denotes pears from East Asia.

*Erect small deciduous tree, sometimes spiny, up to 15 m tall; young branches glabrous or more often woolly-pubescent. *Leaves ovate-oblong, rarely ovate, broadly ovate or ovate-orbicular in cultivars, 7-15 cm × 4-6 cm, rounded at base, acuminate at apex, sharply setose-serrate with usually slightly appressed teeth, glabrous or slightly floccose when young; petioles 3-4.5 cm long. *Inflorescences in terminal umbellate corymbs, mainly on spurs, glabrous or floccose at first, flowering with 6-9 flowers before or with unfolding of leaves, pedicels 3-5 cm long; flowers 3-3.5 cm in diameter; calyx tubular, lobes long-acuminate, almost twice as long as tube; petals ovate, white; stamens 20, anthers usually red; ovary (4-)5-locular, styles (4-)5, glabrous. *Fruit a pyriform to subglobose pome, 2-3 cm in diameter but up to 15 cm in cultivars, brown or yellow, often reddish-brown; flesh rather hard, in wild and primitive types with many stone cells; walls of locules cartilaginous. *Seeds blackish.

''-P. [[Pyrus ussuriensis]]'' is a species from north-east China, eastern Soviet Union, Korea and Japan and is also cultivated in northern Indo-China, Canada and the United States. It is the most cold-resistant pear species with small sweet-sour, attractive and aromatic fruits.

''-P. [[Pyrus pashia]]'' D. Don occurs from Afghanistan, India and northern Burma to south-west China. It is the species most adapted to a hot humid climate. It is cultivated on a very limited scale in Indo-China and northern India. Its fruits are small and rather insipid. They need to be stored for several weeks to become edible. The flesh of some cultivars is nearly black.

''-P. [[Pyrus bretschneideri]]'' Rehder originates in western and central China; it has sweet, juicy, white-fleshy fruits and is also cultivated in Japan and the United States.

''-P. [[Pyrus lindleyi]]'' Rehder originates in China and is also cultivated in Japan and northern Indo-China.

In Asia cultivars are mostly grafted onto seedlings of ''P. pyrifolia.'' . ''P. betulaefolia'' Bunge may be used as a rootstock on heavy wet soils and on light calcareous soils. ''P. calleryana'' Decaisne is generally used as a stock in Florida and has been recommended for hot climates. Most nashi cultivars appear to be incompatible with the European pears and quinces ( ''Cydonia oblonga'' Miller). Dwarfing rootstocks are not available. Rootstocks are grafted or budded during the rest period, preferably at the beginning. Nashi seeds should be planted immediately after they have been extracted from the fruit. Once dried, they pass into a dormant state, which can only be broken by stratification.

Whereas the common sand pear suffers little from diseases and pests, the improved cultivars require fairly intensive crop protection. "Nijiseiki" and several other older, clear-skinned cultivars are very susceptible to black spot disease caused by ''Alternaria kikuchiana'' ; fruits require bagging and about 10 applications of organic phosphorus for protection. Other important diseases are scab ( ''Venturia nashicola'' ) and rust ( ''Gymnosporangium haraeanum'' ). Nashi is less susceptible to fire blight ( ''Erwinia amylivora'' ) than the European pear and some cultivars have considerable resistance. Trunk canker ( ''Phomopsis'' sp.), nectria canker ( ''Nectria cinnabarina'' ) and powdery mildew ( ''Phyllactinia corylea'' ) may cause problems in some cultivars.

A very large number of pests attack the nashi, especially the oriental fruit moth ( ''Grapholita molesta'' ), oriental pear moth ( ''Monema flavescens'' ) and peach fruit moth ( ''Carposina niponensis'' ). Birds of several species are another serious problem.

L.P.A. Oyen