Fungicide use reduction in apple production—potentials or pipe dreams?

Abstract

Reduction in pesticide use in response to consumer pressures is seen as a major issue in many crops. Fungicides comprise the greater proportion of pesticides applied to apples. Potential methods to reduce their usage have been available for a considerable period of time. These are examined under five broad areas: epidemiological (manipulation of current practices), non-conventional fungicides, biological control with microorganisms, disease-resistant varieties, and isolation. The application of these concepts to commercial horticulture in Australia and the economics and social aspects of reduced-input disease control are discussed. The most likely chance for successful adoption of practices to reduce fungicide usage probably lies with manipulation of current practices. These include a reduction in dose rates associated with inoculum suppression and cessation of apple scab treatments at the end of the primary infection period where good control of the disease has been maintained. Biological control offers promise in the control of post harvest diseases. Disease resistant apple varieties offer scope for niche markets demanding reduced pesticide growing systems. The impediments to reduced fungicide usage are seen as both sociological and financial. The benefits of decreased pesticide usage are largely public, whilst the risks of loss are private. Unless these risks can be compensated for, perhaps with a price premium for low-fungicide fruit, it is unlikely that growers will implement such strategies. The variation in the amount of fungicides used successfully by different growers does, however, give scope to bring total usage by the industry down to a practical minimum.