Do some IPM concepts contribute to the development of fungicide resistance? Lessons learned from the apple scab pathosystem in the United States.

One goal of integrated pest management (IPM) as it is currently practiced is an overall reduction in fungicide use in the management of plant disease. Repeated and long-term success of the early broad-spectrum fungicides led to optimism about the capabilities of fungicides, but to an underestimation of the risk of fungicide resistance within agriculture. In 1913, Paul Ehrlich recognized that it was best to 'hit hard and hit early' to prevent microbes from evolving resistance to treatment. This tenet conflicts with the fungicide reduction strategies that have been widely promoted over the past 40 years as integral to IPM. The authors hypothesize that the approaches used to implement IPM have contributed to fungicide resistance problems and may still be driving that process in apple scab management and in IPM requests for proposals. This paper also proposes that IPM as it is currently practiced for plant diseases of perennial systems has been based on the wrong model, and that conceptual shifts in thinking are needed to address the problem of fungicide resistance.