Fungicides and their role in disease management

Fungal diseases are known to affect produce quality on most crops and to cause severe economic losses worldwide. The use of fungicides has been for a long time the main tool to control many economically important fungal pathogens. In the last decades, increased public concern on food safety and environmental impact of farming activities has led regulatory Authorities to adopt very stringent rules on the evaluation and authorization of plant protection products (PPPs), especially for toxicological and environmental negative side effects related to their use. As a result, the development of new PPPs has been addressed at reducing their toxicity towards humans, mammalians and non-target species. In this framework, agrochemical firms have made available several new fungicides with novel specific (single-site) modes of action. Many of them have penetrant properties, are very selective, showing specific activity against target pathogens, as well as enhanced efficacy as compared to traditional multisite fungicides (i.e., carbamates, copper compounds, dithiocarbamates, quinones, sulphur, thiophtalimides, etc.). On the other hand, their single-site modes of action make them at moderate to high risk of inducing fungicide resistance in target pathogens and, hence, anti-resistance strategies must be carefully implemented in their use. Nowadays, about 200 active substances are available, with almost 40 different known specific target sites, plus a number of chemicals having multi-site or unknown mode of action. The increased availability of fungicides allows a more flexible and effective planning of crop protection strategies well fitting to Integrated Pest Management (IPM) principles. Yet, it requires a constant update of technical and scientific expertise by farmers and advisors. This review focuses on the main features of the most commonly used fungicides and their role in disease control in the overall approach to IPM aiming at improving cropping sustainability.