SOME APPLICATIONS OF LABORATORY BIOLOGICAL TESTS TO THE EVALUATION OF FUNGICIDES

Abstract

Summary Laboratory sorting‐out tests on glass slides have shown the relative fungicidal value of a number of rubber accelerators and other organic sulphur derivatives. The most toxic of these materials, when tested on leaves, gave no promise of being of use in the field. In laboratory leaf tests using spray supplements the adverse influence of sulphite lye on tenacity was illustrated by spore germination experiments. Loss of tenacity was similarly demonstrated in sprays including oils emulsified with sulphite lye. A limited number of comparisons with field trials indicates that the laboratory leaf test may be used as an indicator of the fungicidal value of a spray material against Venturia inaequalis and V. pirina, but that in general it gives results less favourable to the fungicide than those from corresponding field trials.