Rationale and Perspectives on the Development of Fungicides

Abstract

Fungicides continue to be essential for the effective control of plant diseases. New classes of fungicides with novel modes of action are being developed in the 1990s. These include the strobilurins, phenylpyrroles, anilinopyrimidines, phenoxyquinolines, and compounds that trigger defense mechanisms in the plant. For the foreseeable future, new toxophores will be identified through a process of random screening, with natural products representing a rich source of fungicide leads. Progress is being made in the development of high-throughput screens comprised of target enzyme sites or cell-based assays; these techniques will improve the probability of discovery. Following the identification of suitable leads, biorational design is used to optimize specific properties. In vivo glasshouse screens and field trials are expected to remain the dominant methods for characterizing new compounds. Low toxicity to humans and wildlife, low environmental impact, low residues in food, and compatibility with integrated pest management (IPM) programs are increasingly important considerations in the selection of fungicides for development.

Stimulateurs des défenses naturelles des plantes : une nouvelle stratégie phytosanitaire dans un contexte d’écoproduction durable.

“…Il n'est plus certain aujourd'hui que la capacité d'invention de l'industrie agrochimique pourra dépasser la capacité d'adaptation des agents pathogènes (Leroux et al 2002). Au cours des dernières années, la réglementation en matière d'homologation de pesticides tant en Europe qu'aux États-Unis s'est tellement alourdie que seules quelques grosses compagnies agrochimiques comme Syngenta ou Bayer CropScience sont encore capables d'assumer les coûts associés à la multitude de tests toxicologiques et écotoxicologiques requis (Knight et al 1997). Outre cet aspect, la diminution progressive du nombre de matières actives disponibles sur le marché aura pour conséquence une augmentation du coût de la protection phytosanitaire, en plus d'engendrer des situations où certains agents pathogènes agressifs ne seront plus contrôlés.…”

Natural Fungicides Obtained from Plants

“…Naturally occurring plant products are important sources of antifungal compounds with low toxicity to mammals and safe to the environment which may serve as substitutes for synthetically produced fungicides. It was later suggested that these compounds might be developed either as products by themselves or used as starting point for synthesis (Knight et al, 1997).…”

Antibacterial to antifungal conversion of neamine aminoglycosides through alkyl modification. Strategy for reviving old drugs into agrofungicides

“…10 Direct application of fungicides remains the prevalent strategy to control these diseases. 10 However, concerns with inconsistent and declining effectiveness due to resistance, environmental impacts, animal and human toxicity and costs continue to challenge their use. Heavy use of triazole agrofungicides are linked to recent rises in human cases of invasive aspergillosis resistant to antifungal azoles.…”