Triazole vs SDHI based fungicides: the incidence of septoria leaf blotch (Mycosphaerella graminicola) in winter wheat varieties and its impact on grain yield

摘要

The results reported in the paper confirmed that triazole and non-SDHI (succinate dehydrogenase inhibitor) based fungicide programmes alone were not effective in controlling septoria (septoria leaf blotch caused by Mycosphaerella graminicola). However, their effectiveness in controlling disease and enhancing yield was significantly improved when used either in a mixture or in a sequence with SDHI based fungicide products. Significant yield differences among varieties in terms of their responses to different fungicide programmes and drilling date were noticed. Earlier drilling had a very negative effect on the level of disease control obtained from a range of fungicide programmes for the susceptible variety Dickens and consequently yield compared with moderately resistant variety Crusoe. A triazole + SDHI fungicide programme increased yield by 4.2 and 4.01 ha~(-1) for Solstice and Dickens respectively compared with their corresponding untreated plots. The same fungicide programme gave a modest yieldenhancement of 1.8 and 2.4 t ha~(-1) for Skyfall and Solace respectively. This tends to suggest that for moderately resistant varieties such as Crusoe, Skyfall and Solace there may be more scope to reduce doses of fungicide programmes. Further trials are being conducted to investigate the effect of drilling date and fungicide programmes on disease incidence and grain yield of varieties with different levels of septoria resistance at the Agrii Technology Centre-Swindon.