South Africa Wine Research Projects

2. VITICULTURE RESEARCH PROJECT IN PROGRESS

NEW PRUNING WOUND PROTECTION STRATEGIES AGAINST TRUNK PATHOGENS IN ROOTSTOCK MOTHER VINES

P04000333 Dr Minette Havenga, ARC Infruitec-Nietvoorbij, Stellenbosch Project is co-funded by the ARC Infruitec-Nietvoorbij Start date: 2023

AIM AND INDUSTRY RELEVANCE: A previous project (P04000108) concluded that rootstock mother vine pruning wounds remained susceptible to Phaeomoniella chlamydospora infections for up to 42 days after pruning. Although several chemical, biological and chemical + biological treatments reduced P. chlamydospora inci dences in artificially inoculated Ramsey and 101-14 Mgt. pruning wounds, the study recommended that more pathogens and rootstock varieties be investigated. Fungicide mixtures will also have to be evaluated to broaden the efficacy of treatments to protect vines against the onslaught of several pathogen groups that all differ in their sensitivity towards fungicides. The use, availability and range of fungicides are under increased pressure worldwide. The search for alternative or biological control agents is crucial to securing sustainable grape production and market access. The study aims to evaluate chemical and biological control agents in various combinations to provide effective pruning wound protection against a range of grapevine trunk pathogens to pro duce high-quality propagation material. There is no published literature on the use of chemicals or biological control agents on rootstock (Vitis spp.) pruning wounds. All previous studies were done on wounds in vineyards (Vitis vinifera) and were not always tested against a wide range of grapevine trunk disease pathogens. The duration of rootstock wound susceptibility across a wide range of grapevine trunk disease pathogens is unknown in SA and worldwide. The benefit of the project to the industry will be a significant contribution towards producing high-quality grapevine propagation material that will contribute to higher take percentages in grapevine nurseries and better establishment of young vines in new vineyards.

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SOUTH AFRICA WINE RESEARCH 2024