The control of crop diseases still largely relies on spray applications of standard synthetic fungicides. As a result, the development of fungicide resistance by pathogens is a major limiting factor for the control of diseases. In this paper, the recent outbreak of practical resistance to fungicides including sterol demethylation inhibitor (DMI), Quinone outside inhibitor (QoI), and succinate dehydrogenase inhibitor (SDHI) fungicides as well as the progress of related research will be discussed. To combat resistance development, the Research Committee on Fungicide Resistance, the Phytopathological Society of Japan, was established in 1991 and has been conducting several activities. The Committee made a guideline indicating how to use at-risk fungicides. The occurrence of fungicide resistance may rather increase in the future as the choice of fungicides is often difficult due to the lack of effective alternatives. Development and integration of disease management tools such as disease-resistant or -tolerant cultivars and non-fungitoxic disease resistance inducers need to be accelerated more rapidly not only to dissolve the problem of fungicide resistance but also to reply public concerns about agrochemicals.

• Hideo Ishii(School of Agriculture, Kibi International University)