Alternatives to conventional fungicides for the control of citrus postharvest green and blue moulds

Abstract

Purpose of review: This article reviews research based on the evaluation of postharvest control methods alternative to conventional chemical fungicides for the control of citrus green and blue moulds, caused by the pathogens Penicillium digitatum and P. italicum, respectively. Emphasis is given to advances developed during the last few years. Potential benefits, disadvantages and commercial feasibility of the application of these methods are discussed. Findings: Substantial progress has been accomplished in selecting and characterising new effective physical, chemical and biological control methods. However, their widespread commercial implementation relies, in general, on the integration of different treatments of the same or different nature in a multifaceted approach. For satisfactory penicillium decay control, this postharvest approach should be part of an integrated disease management (IDM) programme in which preharvest and harvest factors are also considered. Limitations: The lack of either curative or preventive activity, low persistence, high variability, inconsistency or excessive specificity are general limitations associated with the use of alternatives to synthetic fungicides as stand-alone treatments. Furthermore, the risk of adverse effects on fruit quality, technological problems for cost-effective application, or the availability of new conventional fungicides for traditional markets are additional reasons that may hinder the broad commercial use of such treatments. Directions for future research: As we learn more about the fundamental basis underlying host-pathogen interactions and how they are influenced by direct or indirect protective effects of existing or new single alternative treatments, more effective methods of applying and combining complementary approaches for additive or synergistic effects will emerge. Research should provide appropriate tools to tailor the application of these nonpolluting postharvest control systems and, further, the complete IDM strategy for each specific situation (ie, citrus species and cultivar, climatic and seasonal conditions, destination market, etc).