Dealing with Grape Vine Trunk Disease
Chris Cooper and Rob Saunders, vine specialists in the Hutchinsons Horticultural Team, share their thoughts on vineyard priorities for February. The main task undertaken in the vineyard in winter months is pruning and how to reduce Grape Vine Trunk Disease (GTDs) infection.
Any open wound may be a portal for infection, but larger wounds of more than 15mm on the main stem are at greatest risk. Rain promotes spore release and dispersal, so ideally avoid pruning when heavy rain is forecast within the next 24hrs and use a wound protection product on the larger wounds.
Globally a lot of work is and has been carried out to identify infective agents and manage or prevent the infections from occurring. The consensus is that, of the products approved for use in the UK, those based on tebuconazole, such as Nativo or Unicorn, applied soon after pruning will give the best control. With tebuconazole undergoing an EU re-registration and its continued availability uncertain, Hutchinson’s have been investigating alternatives.
BlocCade: is available to seal and protect the wound, either brushed on or sprayed on very soon after making the cut. This acts as a physical barrier. Apply before the sap is flowing; otherwise the product is pushed off.
Solufeed Garlic Wound Protection Paint: An Australian concept, it can be painted on and used in organic or conventional grown vineyards. Garlic, rich in thiols (sulphur compounds), is known to inhibit fungal infection, allowing wounds to callous over naturally. It is now in its fourth season of use and has worked well. Once again apply before the sap flow starts.
Chris says that Hutchinsons are working with the plant protection company Belchim trying to bring a range of products to the UK market for use on Wine Grapes. One these is a strain of Trichoderma atroviride, an organically based biological control agent, sold in continental Europe as Vinetec and hopefully available in the UK via Mutual Recognition by the 2019/20 pruning season.