Optimising input and performance of triazole fungicides in winter wheat by monitoring residual activity

Abstract

The aim of this research project was to develop a cost effective method of detecting fungicide levels in wheat plants, and to use the results to decide if there was sufficient fungicide to provide effective control of Septoria tritici.

Antibodies were developed which could detect the fungicide tebuconazole. A laboratory method was then produced which used these antibodies in an ELISA test to detect tebuconazole residues in plant sap. The laboratory method was compared with conventional (but expensive) analytical procedures, and they correlated well. The test was accurate in the range of 0.01 ppm up to 20 ppm, and this range corresponded to tebuconazole residues present in plant material which had an effect on the control of diseases.

Tests of the ELISA based laboratory kit, using samples from field experiments, demonstrated that:

i) the fungicide residue levels quantified by the test were consistent with the doses applied to the crop.
ii) decay of the active ingredient over time could be accurately measured.
iii) within an experiment, residue levels related well to the level of disease control obtained. However, some variation in the relationship was found when making comparisons between experiments carried out at different sites and different years.

A prototype kit was produced using the antibodies. During its development, consideration was given to the techniques and reagents used to ensure it would be robust enough to be used in a field situation. Results from the prototype field kit corresponded well to the laboratory kit.