Recent developments and challenges in chemical disease control - a review

The use of chemical fungicides to control plant diseases is an integral component of crop management. Although fungicides have been used to good effect in agriculture since the 1940s, the introduction of new fungicides is an essential element to provide sustained control of major crop diseases. The need for new and innovative fungicides is driven, among other factors, by resistance management, regulatory hurdles, and increasing customer expectations. New fungicides can be discovered either within established mode of action groups, ideally with low resistance risk (robust modes of action), or in areas with completely novel modes of action. Compounds having a novel mode of action are of course of special interest, since they play a key role in resistance management strategies, but equally important are new fungicides with enhanced characteristics such as systemicity, curativity, and longevity of disease control. With the background of increasing registration hurdles, increasing costs, and increasing market needs, the current market position of major crop protection fungicides needs to be reviewed, along with the consideration of current and future market needs. An analysis of the situation regarding new fungicidal compounds in late development or recently introduced to the market suggests that considerable innovation continues to be delivered in the chemical fungicide area. New modes of action are quite rare in some segments (major new fungicides are mainly SDHIs), but seem to be more frequently discovered for the control of oomycetes. Potential reasons for this are discussed.