incidence, distribution and expression of Australian grapevine yellows, restricted growth and late season leaf curl diseases in selected Australian vineyards

• Published in: Annals of applied biology 2004-04, Vol.144 (2), p.205-218
• Main Authors: Constable, F.E, Jones, J, Gibb, K.S, Chalmers, Y.M, Symons, R.H
• Format: Article
• Language: English
• Subjects: Australian grapevine yellows; Australian grapevine yellows disease; Australian grapevine yellows phytoplasma; Biological and medical sciences; Chardonnay variety; disease incidence; epidemiological studies; Fundamental and applied biological sciences. Psychology; incidence; late season leaf curl; late season leaf curl disease; Phytoplasma; phytoplasmal diseases; restricted growth; restricted growth disease; Shiraz variety; Spatial distribution; temporal; Vitaceae; Vitis vinifera; wine cultivars; wine grapes
• ISSN: 0003-4746; 1744-7348
• DOI: 10.1111/j.1744-7348.2004.tb00335.x

Summary Surveys were conducted in four Chardonnay vineyards for 3 to 6 years and one Shiraz vineyard for 3 years to determine the yearly percentage of grapevines affected by Australian grapevine yellows disease (AGYd), restricted growth disease (RGd) and late season leaf curl disease (LSLCd). In each of the Chardonnay vineyards in each year, all three diseases were characterised by remission of disease in some grapevines, recurrence of disease in other grapevines and new observations of disease in previously unaffected grapevines. The pattern of temporal incidence of each disease was different between vineyards for the survey period. Although Koch's postulates have not been fulfilled, phytoplasmas are considered to be the most likely cause of AGYd. While some grapevines exhibited a combination of AGYd and RGd or AGYd and LSLCd, both RGd and LSLCd can occur independently of AGYd. Statistical analyses using log‐linear models also indicated that RGd and LSLCd were not always associated with AGYd. Thus, it is possible that phytoplasmas are not the cause of RGd or LSLCd and their association is coincidental. Expression of AGYd in Shiraz grapevines occurred later in the season compared to Chardonnay. Very little recurrence of AGYd was observed in the Shiraz grapevines indicating that the variety Shiraz responds differently to phytoplasma infections, assuming that AGYd in Shiraz is a phytoplasma caused disease. RGd and LSLCd were not observed on any grapevines in the Shiraz vineyard.