Polyphasic identification of preharvest pathologies and disorders in avocado cv. Hass

Abstract

Diseases and disorders are one of the main limitations of avocado crops for export and national markets. However, they are poorly studied in tropical countries such as Colombia. The objective of this research was to evaluate a polyphasic approach for the diagnosis of pathologies and disorders associated with avocado cv. Hass in nurseries and crop fields located in Antioquia, Colombia. Results allowed the identification of several diseases and disorders present on different tissues in all stages of plant development. The root rot disease was associated with 10 microorganisms and two abiotic disorders. Different organs and tissues of avocado plants were affected by pathogens such as Lasiodiplodia theobromae, Colletotrichum gloeosporioides sensu lato, and Phytophthora palmivora. Pathogens that had not been previously reported in Colombia were identified, and among them P. palmivora, Fusarium oxysporum sensu lato, Phytopythium vexans, Phomopsis sp., and Pythium cucurbitacearum stand out. Abiotic disorders such as hypoxiaanoxia, root atrophy, fruit sunburn, and hailstorm damage were also identified. The etiology of peduncle ringing was not identified. Polyphasic diagnosis of pathologies and disorders is an appropriate approach as part of an integrated disease management program in avocado cv. Hass crop. This work is a reference tool on basic aspects associated with the detection of disorders and pathologies in avocado and the taxonomy of the microorganisms involved.

Keywords

• root rot
• abiotic and biotic causal agents
• diseases in nurseries and field
• detection techniques