A procedure for collecting and interpreting data from field experiments with nematicides.

SUMMARY In the first part of the paper the main criteria necessary to study the nematicidal properties of different chemical compounds are discussed. A procedure to record qualitative variables (plant vigour, gall index) is also discussed. In the second part a statistical approach, liable to increase the power of the techniques as cornpared with conventional procedures, is treated. This allows reference to the entire nematode population including al1 species present, to demonstrate similarities of and differences between the pesticides studied and to utilize qualitative and quantitative data simultaneously. Techniques involved belong to the non parametric and newly developed multivariate statistical methods such as : factor analysis, discrimant analysis, Friedman’s variance analysis and rank correlations. RESUMB