Abstract: Novel generic antibodies are provided that are specific to groups of organophosphates, particularly to a class of organophosphate pesticides in common usage. Further provided are compounds and methods for raising these antibodies, test kits containing them and methods for their use. The antibodies targeted at low molecular weight (i.e. below MW 1000) organophosphorous pesticides methacrifos, pirimphos methyl, etrimfos, fenitrothion, chlopyrifos methyl, dichlorovos and malathion. Preferred conjugates of the invention are of the formula (RO).sub.2 --P(S)--Z--?Y!-Protein wherein R is lower alkyl and Z is as O, S or --NH--, Y is a spacer group and "Protein" indicates a protein suitable for use in hapten protein conjugates for the purpose of raising antibodies and antisera. Typical and preferred proteins are bovine serum albumin, ovalbumin from chicken egg, keyhole limpet hemocyananin and mixtures of these.