An ELISA which was used to detect and quantify ingested rice planthoppers in arthropod predators collected from paddy fields was developed. The detection limit of the assay was about one hundredth of an homogenised adult or 3￣5th instar nymph rice planthopper. Tests with 2 species of rice planthopper( Sogatella furcifera and Nilaparvata lugens ) showed that those which had been used as the principal immunogens reacted most strongly in the assay and no evidence of significant cross reaction was found with each other or with any other species and with rice material. Among tested predatory species

Ummeliata insecticeps

Pirata subpiraticus

clubionid

and salticid had the highest positive reaction rates.