Plant Pathology (2013) 62, 1226-1237

M.A. Whitelaw-Weckert, L. Rahman, L.M. Appleby, A. Hall, A.C. Clark, H. Waite and W.J. Hardie (2013)
Co-infection by Botryosphaeriaceae and Ilyonectria spp. fungi during propagation causes decline of young grafted grapevines
Plant Pathology 62 (6), 1226-1237
Abstract: Decline of newly planted, grafted grapevines is a serious viticultural problem worldwide. In the Riverina (New South Wales, Australia), characteristic symptoms include low fruit yields, very short shoots and severely stunted roots with black, sunken, necrotic lesions. To determine the cause, roots and wood tissue from affected plants in 20 vineyards (Vitis vinifera cv. Chardonnay grafted to V. champini cv. Ramsey rootstock) were assayed for microbial pathogens. Ilyonectria spp. (I. macrodidyma or I. liriodendri, producers of phytotoxin brefeldin A, BFA, and cause of black foot disease of grapevines) and Botryosphaeriaceae spp. (predominantly Diplodia seriata) were isolated from rootstocks of 100 and 95% of the plants, respectively. Togninia minima and Phaeomoniella chlamydospora (cause of grapevine Petri disease) were isolated from 13 and 7% of affected plants, respectively. All Ramsey rootstock stems of grafted plants sampled from a supplier nursery were infected with Ilyonectria spp. and D. seriata. Diplodia seriata, but not Ilyonectria spp., was also isolated from 25% of canes sampled from the rootstock source block. Root inoculation of potted, disease-free Chardonnay plants with Ilyonectria isolates from diseased vineyards caused typical disease symptoms, while co-inoculation with Botryosphaeriaceae spp. increased disease severity. This is the first study to show that a major cause of young grapevine decline can be sequential infection by Botryosphaeriaceae from rootstock cuttings and Ilyonectria spp. from nursery soil. Although the Petri disease fungi were less common in young declining grafted grapevines in the Riverina, they are likely to contribute to the decline of surviving plants as they mature.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Melanie A. Whitelaw-Weckert

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diplodia mutila	Grapevine (Vitis)
	Phaeomoniella chlamydospora	Grapevine (Vitis)
	Phaeoacremonium minimum	Grapevine (Vitis)
	Diplodia seriata	Grapevine (Vitis)
	Dactylonectria macrodidyma	Grapevine (Vitis)
	Ilyonectria liriodendri	Grapevine (Vitis)