Changes

*''Psidium aromaticum'' Blanco (1837).

*Guava (En). *Goyavier (Fr). *Brunei: jambu batu (Malay), biyabas

*Shallow-rooted shrub or small tree, up to 10 m tall, branching from the base and often producing suckers. Bark smooth, green to red-brown, peeling off in thin flakes. Young twigs 4-angled and ridged, pubescent. *Leaves opposite, glandular; petiole 3-10 mm long; blade elliptical to oblong, 5-15 cm × 3-7 cm, glabrous above, finely pubescent beneath, veins prominent below. *Flowers solitary or in 2-3-flowered cymes, axillary, ca. 3 cm in diameter; calyx lobes 4-6, 1-1.5 cm long, irregular, persistent; petals 4-5, white, 1-2 cm long; stamens numerous, 1-2 cm long; ovary 4-5-locular; style 1.5-2 cm long, stigma capitate. *Fruit a berry, globose, ovoid or pyriform, 4-12 cm long, surmounted by the calyx lobes; exocarp green to yellow; mesocarp fleshy, white, yellow, pink or red, with stone cells, sour to sweet and aromatic. *Seeds usually numerous, embedded in pulp, yellowish, bony, reniform, 3-5 mm long.

Trees may wilt following infection by various soil fungi and in Thailand root rot caused by ''Phytophthora'' spp. is also thought to kill trees. The leaves are little affected by diseases, but anthracnose ( ''Colletotrichum gloeosporioides'' ) which is more serious on the fruit, also affects the leaves. Blossom-end rot can become a serious disease in the rainy season; there may be physiological as well as pathological causes. Mucor rot, caused by the fungus ''Mucor hiemalis'' , spoils fruit punctured by insects. One often sees young fruit blackened and mummified by ''Glomerella cingulata'' or ''Diplodia natalensis'' . Fruit canker, circular raised corky spots infected by ''Pestalotia psidii'' , is also common. Orchard sanitation in the form of early removal of infected plant parts, helps to reduce infections. Chemical control may be needed in the rainy season; dithane is recommended against blossom-end rot and fruit canker, with additional control of anthracnose.

Fruit flies are the most important pest; guava is a major host to species of ''Anastrepha'' , ''Ceratitis'' , ''Dacus'' and ''Argyresthia'' . Bagging the fruit is the main control method in continuously cropped orchards; if the crop is cycled, spraying with fenthion or use of bait sprays provide additional means of control. Sucking insects such as scales, mealy bugs and thrips can largely be checked by predators and control of ants. Leaf-eating caterpillars and beetles may severely damage young trees; early detection greatly facilitates control by spot treatment.