Diagrammatic scale of severity for postharvest black rot (Ceratocystis paradoxa) in coconut palm fruits

Pedro Henrique Dias Dos Santos,Beatriz Murizini Carvalho,Silvaldo Felipe Da Silveira,Maria Das Graças Machado Freire,Vicente Mussi-Dias

doi:10.1590/0100-5405/170792

Pedro Henrique Dias Dos Santos, Beatriz Murizini Carvalho + Show 3 more

Open Access

https://doi.org/10.1590/0100-5405/170792

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Abstract

ABSTRACT One of the major bottlenecks in the postharvest commercialization of coconut fruits is the black rot disease, caused by the fungus Ceratocystis paradoxa. This disease has been neglected in the main production areas or associated with other coconut diseases. To date, there are no standardized methods for assessing the intensity of such a problem. In this sense, the aim of our study was to prepare and validate a diagrammatic scale to evaluate the disease severity in coconut fruits. We also tested the scale applicability comparing distinct C. paradoxa isolates on inoculated fruits. For such quantification, the fruit longitudinal sectioning was necessary, allowing the visualization of internal symptoms. The proposed scale showed good repeatability and high reproducibility, with absolute errors around 8%, while the coefficient of determination presented an average of 91% with the aid of the scale and of 59% without the scale. In addition, symptom analyses showed that the outer necrosis does not match the internal damage. Therefore, we suggest in this study that the severity estimate of this disease be obtained by using the presented scale.

Highlights

Um dos principais problemas na comercialização de frutos de coco em póscolheita tem sido a podridão negra, causada pelo fungo Ceratocystis paradoxa
Palavras-chave: Epidemiologia, Patometria, Severidade de doença In Brazil, coconut palm (Cocos nucifera L.) crop has been affected by stem bleeding disease, caused by the fungus Ceratocystis paradoxa (Dade) C
C. paradoxa develops and infects, causing black rot, often confused with stem-end rot in fruits, which has as etiologic agent the fungus Lasiodiplodia theobromae (Pat.) Griffon and Maubl, another

Summary

Introduction

Um dos principais problemas na comercialização de frutos de coco em póscolheita tem sido a podridão negra, causada pelo fungo Ceratocystis paradoxa. Considering coconut fruit production, which is destined to fresh fruit commercialization and exportation for coconut water consumption, that fungal species was recently identified causing fruit rot or fruit black rot [15] Diseases caused by this fungus, leading to postharvest losses, have affected other fruit crops such as peach palm [10], cocoa [14], date palm [19], pineapple [3] and banana [2]. Lack of information about its pathogenesis has led to variations in the fungus latent period, stipe, distribution and colonization of other parts of the infected plants, making difficult to establish effective measures to prevent and control the disease, especially when the fungus focuses on inflorescence, infructescence and fruit in the postharvest In the latter case, C. paradoxa develops and infects, causing black rot, often confused with stem-end rot in fruits, which has as etiologic agent the fungus Lasiodiplodia theobromae (Pat.) Griffon and Maubl, another. Black rot intensity varies according to the environmental conditions and the presence of a latent fungus; internal rot can be observed, even in green coconuts, making their commercialization unfeasible and changing the taste of their water [22, 15]

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