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Effects of some systemic imidazole and triazole fungicides on white clover and symbiotic nitrogen fixation by Rhizobium trifolii
Author(s) -
FISHER D. J.,
HAYES ANN L.
Publication year - 1982
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1982.tb00796.x
Subject(s) - fungicide , biology , triadimefon , propiconazole , nitrogen fixation , agronomy , thiram , rhizobia , rhizobium , horticulture , inoculation , genetics , bacteria
SUMMARY Effects of prochloraz, imazalil, diclobutrazol, triadimefon and propiconazole were studied. Compared with most systemic fungicides previously tested they were all relatively toxic to R. trifolii on agar. Effects of soil residues of the compounds on the growth and nitrogen fixing capacity of white clover were measured. The lowest concentration of the fungicides used was that which would be present if all the active ingredient from a single application remained unchanged and evenly distributed in the top 5 cm of soil. This concentration of diclobutrazol decreased the size and weight of 11‐wk‐old clover plants. The rate of nitrogen fixation was reduced by twice this concentration and root nodulation by four times this amount. None of the other fungicides had any significant effect. The possibility of field application of diclobutrazol to cereals causing damage to clover crops is discussed. It is questionable whether harmful soil residues will ever accumulate from normal usage of the fungicide but exceeding the recommended rate of application, or application to cereals undersown with clover, might cause undesirable effects on the clover.