Three fungicide treatments: untreated, epoxiconazole and kresoxim-methyl + epoxiconazole were compared on the winter wheat cultivar Pastiche. Assessments of disease and green leaf area down the canopy were made, as well as quantitative measures of leaf greenness using spectral transmittance techniques. Significant differences were found in SPAD value and NIR/R ratios between both the fungicide treatments and the untreated control, and between the two fungicide treatments. The kresoxim-methyl + epoxiconazole treatment gave a significantly higher mean SPAD value and NIR/R ratio than the epoxiconazole treatment on all three leaf layers. Transmittance spectra of leaves from the two fungicide treatments showed that transmittance was decreased in the red region and increased in the NIR region of the spectra in the kresoxim-methyl + epoxiconazole treatment. These differences indicated that the addition of kresoxim-methyl to the epoxiconazole resulted in a delay in leaf senescence and an increase in the duration of green leaf area. It is suggested that the significant yield increases of 0.93 and 0.53 t/ha of the kresoxim-methyl + epoxiconazole treatment compared with the untreated and epoxiconazole treatments, respectively, were due to an increase in green leaf area duration. Differences in the amount and duration of green leaf area between the two fungicide treatments and the untreated control were due primarily to disease control whilst differences between the two fungicides were due to kresoxim-methyl delaying leaf senescence.

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