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The changes in the physicochemical properties of rices which had different amylose contents were studied when the rice was stored at 2°C and 29°C as rough rice, milled rice, defatted milled rice, and as starch. Changes in hardness index, water absorption, stickiness, viscosity, salt‐soluble protein, free fatty acids, and carbonyl compounds during storage are discussed.

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Oxalic acid, isolated from leaf sheath extract of rice, has been identified as a potent sucking inhibitor against the brown planthopper. Potassium and sodium oxalate at concentrations of 0.1%–0.2% completely inhibited sucking on a 15% sucrose solution. Of twelve aliphatic acids commonly present in plants, only oxalic, maleic, and trans‐aconitic acids at 0.1%, significantly reduced sucking activity while Krebs cycle acids, such as citric, malic, and succinic, did not have any inhibitory effect. RÉSUMÉ L'ACIDE OXALIQUE COMME INHIBITEUR DE LA SUCCION DE NIPALARVATA LUGENS STÀL, (HOMOPTERE, DELPHACIDAE) L'acide oxalique, isolé des gaines foliaires du riz, a été identifié comme un puissant inhibiteur de la succion de Nilaparvata lugens. Les oxalates de potassium et de sodium aux concentrations de 0,1% et 0,2% inhibent complètement la succion d'une solution de sucrose à 15%. Parmi les douze acides aliphatiques généralement présents dans la plante, seuls les acides oxalique, maleique et trans‐aconique réduisent significativement à 0,1% l'activité de succion, tandis que les acides cycliques comme les acides citrique, malique et succinique n'ont pas d'effet inhibiteur.