Pierce's Disease of Grapevines: A Review of Control Strategies and an Outline of an Epidemiological Model.

Ifigeneia Kyrkou,Marie-France Sagot,Lars Hestbjerg Hansen,Taneli Pusa,Lea Ellegaard-Jensen

doi:10.3389/fmicb.2018.02141

Abstract

Xylella fastidiosa is a notorious plant pathogenic bacterium that represents a threat to crops worldwide. Its subspecies, Xylella fastidiosa subsp. fastidiosa is the causal agent of Pierce's disease of grapevines. Pierce's disease has presented a serious challenge for the grapevine industry in the United States and turned into an epidemic in Southern California due to the invasion of the insect vector Homalodisca vitripennis. In an attempt to minimize the effects of Xylella fastidiosa subsp. fastidiosa in vineyards, various studies have been developing and testing strategies to prevent the occurrence of Pierce's disease, i.e., prophylactic strategies. Research has also been undertaken to investigate therapeutic strategies to cure vines infected by Xylella fastidiosa subsp. fastidiosa. This report explicitly reviews all the strategies published to date and specifies their current status. Furthermore, an epidemiological model of Xylella fastidiosa subsp. fastidiosa is proposed and key parameters for the spread of Pierce's disease deciphered in a sensitivity analysis of all model parameters. Based on these results, it is concluded that future studies should prioritize therapeutic strategies, while investments should only be made in prophylactic strategies that have demonstrated promising results in vineyards.

Highlights

Pierce’s disease (PD) is a disease that affects grapevines (Vitis vinifera)
Given that the vast majority of control strategies against Xylella fastidiosa subsp. fastidiosa (Xff) vectors aim at glassy-winged sharpshooter (GWSS), this review focuses on GWSS exclusively
There has been a systematic effort to reduce the presence of Xff in vineyards for more than 20 years

Summary

Introduction

The disease is prevalent across the United States (US), from Florida to California, and threatens the country’s $30 billion wine industry (Sanscartier et al, 2012). Since the 1880s, PD has caused the decline of more than 35,000 acres of vineyards in Southern California (SC) (Galvez et al, 2010). The aetiological agent of PD is a gram-negative, plant-pathogenic bacterium, Xylella fastidiosa subsp. The species X. fastidiosa (XYLEFA) comprises three well-established subspecies, which infect different plant hosts (Almeida and Nunney, 2015; Marcelletti and Scortichini, 2016), while the existence of a fourth and a fifth subspecies is in dispute (Marcelletti and Scortichini, 2016; Giampetruzzi et al, 2017). While not all of these hosts are susceptible to PD, XYLEFA negatively

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Conclusion