Fungicide resistance: facing the challenge - a review

Fungicide resistance continues to generate disease control problems in many crops. Experience amassed over the past fifty years has emphasised the importance of diversity in modes of action in anti-resistance strategies. Because of losses, not only from resistance, but increasingly from environmental and health concerns, the number of modes of action has become dangerously small. This paper considers three challenges facing crop protection in the search for durable disease control systems. Greater understanding of the biochemistry surrounding fungal development and pathogenicity provides opportunities for the discovery and development of novel modes of action, and some recent advances in this area are discussed. To ensure sufficient resources available to take a novel discovery forward to a commercial product, a second challenge facing manufacturers involves early assessment of resistance risk. A third challenge facing researchers, manufacturers and growers requires translation of resistance risk into effective and durable disease control strategies in actual crops. At the core of this challenge is using resistance risk evidence obtained in laboratory and glasshouse studies using individual isolates of target pathogens, to evaluate the fitness cost of resistance in pathogen populations in field crops. Increasingly, management of resistance is seen as the integration of fungicides with non-chemical disease control methods. But success of any Integrated Disease Management (IDM) strategy ultimately depends on the ability of growers to maintain production and profitability.