New strategies for the control of avocado fruit diseases

Abstract

Loss of avocado fruit in the marketplace due to anthracnose and stem-end rots is still a major concern for both growers and consumers. The ability of the rot causing fungi, to remain in a dormant or latent phase until after the fruit commences ripening makes disease control very difficult. In a previous project (AV97001), significant advances were made to control rots with the world first discovery that rootstock race affects the severity and incidence of fruit rots. This project aimed to advance these rootstock studies as well as investigate new products available for disease control, assess harvesting methods and evaluate other strategies such as cross-protection using non-pathogenic strains of the fungus (Colletotrichum gloeosporioides) that cause anthracnose rots. This project also included a PhD study into the preharvest disease, pepper spot. This research was also based on a discovery made in the previous project (AV97001) that pepper spot and anthracnose are caused by the same fungus, Colletotrichum gloeosporioides. The pepper spot investigations aimed to answer the questions of how and why the same fungus was able to cause two different disease symptoms and how we can control it.