The occurrence of Pierce’s disease of grapevines and its control strategies in Taiwan

Abstract

PD of grapes caused by Xylella fastidiosa, a xylem-limited bacterium, has been listed as one of the international quarantine plant diseases. From 2002, the Bureau of Animal and Plant Health Inspection and Quarantine launched a survey project to detect PD in Taiwan. So far, a total of 13,666 grapevines were confirmed to be infected by X. fastidiosa via direct isolations and PCR protocols. Other than grapes, the following four plants were confirmed to be the alternative hosts of PD in Taiwan: Diplocyclos palmatus (L.) C. Jeffrey, Ampelopsis brevipedunculata (Maxim.) Trautv var. hancei (Planch.) Rehder., Humulus scandens (Lour.) Merr., and Mallotus paniculatus (Lam.) Muell.-Arg. The 16S rRNA sequences of PD strains isolated from tissues of grapevines exhibiting PD symptoms collected from 5 counties and 4 alternative hosts were compared with X. fastidiosa from other hosts. The phylogenetic trees constructed with neighbour-joining method revealed that X. fastidiosa strains from different hosts could be divided into five subgroups and the PD strains from Taiwan were grouped with grapevine and mulberry strains from the Americas. The control strategies recommended for limiting the spread of PD are as follows: (1) to plant the healthy seedlings and eradicate the PD-like grapevines immediately (2) to eradicate the alternative hosts and the weeds that insect vectors favor (3) to control the population of indigenous insect vectors and avoid the invasion of foreign insect vectors.