Effectiveness of Natural Antifungal Compounds in Controlling Infection by Grapevine Trunk Disease Pathogens through Pruning Wounds

Abstract

Grapevine trunk fungal pathogens, such as Diplodia seriata and Phaeomoniella chlamydospora, can infect plants through pruning wounds. They cause grapevine trunk diseases and are involved in grapevine decline. Accordingly, the protection of pruning wounds is crucial for the management of grapevine trunk diseases. The efficacy of different natural antifungals in inhibiting the growth of several fungi causing grapevine trunk diseases was evaluated in vitro. The fungi showing greater in vitro efficacy were tested on autoclaved grape wood assays against D. seriata and P. chlamydospora. Based on results from these assays, chitosan oligosaccharide, vanillin, and garlic extract were selected for further evaluation on pruning wounds inoculated with D. seriata and P. chlamydospora in field trials. A significant decrease in plant mortality was observed after 2 years of growth in the plants treated with the different natural antifungals compared to the mortality rate observed in infected plants that were not treated with antifungals. Also, the infection rate for the inoculated pathogens was significantly reduced in plants treated with the selected natural antifungals. Therefore, natural antifungals represent a promising alternative for disease control and could provide significant economic benefits for the grape-growing industry. Grapevine trunk diseases are a major threat to the wine and grape industry. They have been reported in most grapevineproducing regions worldwide, causing serious economic losses due to a significant reduction of both yields and the quality of the grapes (1-3). The diseases include Botryosphaeria dieback, esca, Eutypa dieback, Petri disease, black foot, and Phomopsis dieback as the most relevant pathologies.Planting material produced in nurseries is frequently infected with fungal pathogens, especially those involved in Petri and black foot diseases (4, 5). In mature vineyards, pathogens such as Ilyonectria sp. mainly penetrate through the root system (6). However, it is widely accepted that for many pathogens, the annually produced pruning wounds are the main route of entry into young and adult plants (7-9). Consequently, numerous studies have been conducted to assess the susceptibility of pruning wounds to fungal pathogens causing trunk diseases. Susceptibility to Botryosphaeriaceae species has been studied by several authors (8-10). Eutypa lata infection has been extensively analyzed by authors like Munkvold and Marois (11) (8) also studied susceptibility to Phomopsis viticola infection. All of these studies support the hypothesis that pruning wounds are the main route of entry of these pathogens in the plant, and, therefore, the development of measures to protect pruning wounds would be an essential tool in the management of vineyards with better sanitation. Accordingly, numerous tests treating pruning wounds with chemical fungicides and/or biological control agents (BCA) have been carried out. Munkvold and Marois (16) checked the efficacy of natural epiphytes and colonizers of pruning wounds fo...

Use of Endophytic and Rhizosphere Actinobacteria from Grapevine Plants To Reduce Nursery Fungal Graft Infections That Lead to Young Grapevine Decline

“…Accordingly, in recent years, there have been many different studies aimed at controlling or diminishing fungal pathogen infection rates (6,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). Most studies have focused on protecting pruning wounds by applying natural antifungal compounds (12) or different chemical fungicides.…”

Antifungal activity of plant extracts onPhaeomoniella chlamydospora

“…Likewise, rosemary extracts and lemongrass were not efficient in the control of Alternaria solani [23]. Cobos et al (2015) found that garlic extracts, green coffee, lemon peel, propolis, vanilla, chitosan and lichen Evernia prunastri were efficient in vitro control of Botryosphaeria dothidea, Diplodia seriata, Eutypa lata, Ilyonectria macrodidyma, Phaeocremonium th World Congress of Vine and Wine aleophilum, Phaeomoniella chlamydospora and Plasmopara viticola [7].…”

“…The garlic extract was also effective in controlling in vitro Botryosphaeria dothidea, Diplodia a e-mail: carine.rusin@gmail.com seriata andEutypa lata, Macrodidyma Ilyonectri and Phaeocremonium aleophilum [7].…”

Identification the Pathogens Causing Rot Disease in Pomegranate (Punica granatum L.) in China and the Antifungal Activity of Aqueous Garlic Extract

“…Previous studies have found that aqueous garlic extracts have inhibitory effects on bacteria and some fungi [15,16]. Even for A. niger and B. dothidea, it has been proven that different garlic extracts showed antifungal activities [29][30][31][32], but the antifungal effect is related to the extraction solvent, the state of the garlic, the extraction method, and so on. The aqueous and petroleum ether garlic extracts possessed stronger activity and a broader fungicidal spectrum against eight fungal strains compared to a methanol extract [29].…”