Resumen de Detection of grape phylloxera (Daktulosphaira vitifoliae Fitch) by real-time quantitative PCR: development of a soil sampling protocol
D. Giblot Ducray, Ray L. Correll, Cassandra Collins, Alan Nankivell, A. Downs, Inca Pearce, A.C. Mckay, Kathy Ophel-Keller
Background and Aims Quantitative PCR (qPCR) provides the basis for an efficient detection and surveillance system for phylloxera, a devastating pest of grapevines worldwide. This study aimed to develop a sample collection and handling protocol for reliable detection of phylloxera in soil by qPCR.
Methods and Results Quantitative PCR conducted on infested soil samples stored at 10, 20 or 35°C for up to 10 days showed that extended storage did not significantly affect the rate of phylloxera detection. The limit of detection of qPCR was estimated to be 1.5 to 2 phylloxera per 200 g dry soil using samples prepared from phylloxera-infested and non-infested soil in various ratios. Comparison of phylloxera detection rate and numbers between depths, positions and vineyards, in all seasons over 2 years showed that the highest detection rate is obtained with samples taken 0–10 cm deep and 5 cm from the trunk, and that higher numbers are consistently found from mid-summer to early winter.
Conclusions When combined with an appropriate sampling protocol, qPCR allows reliable detection of phylloxera in soil, across sites and seasons.
Significance of the Study The sampling protocol developed in this study will facilitate the adoption of qPCR for large scale monitoring and surveillance of phylloxera by the industry.
