Ever-growing concerns around Leafroll

Tuesday, 22 August, 2017
Sheryl Faure
Growing up in the Winelands I thought Autumn was a magical time as my sisters and I would walk the dogs between rows of vines in our wellingtons. The leaves that we walked on struck me as beautiful, the colours I thought were an indication of happy vines and the richer the burgundy, the more I liked what I saw, not knowing the detrimental effect leafroll has on the vine.

Infected vineyards  show a decline in fruit quality and quantity which ultimately has an effect on crop size.

I recently attended a workshop with VinPro, in collaboration with Vititec, Winetech and Creation Wines in the Hemel and Aarde valley where we were shown the extent of how the virus has spread in the area. Intrigued by this and being in the heart of the beautiful Hemel and Aarde valley where one finds such contrasting blocks of vineyard between neighbours, somewhat resembling a quilt, we were told by Jean-Claude Martin, owner of Creation Wines, that one can combat this virus. This is however a timely and painfully expensive process and takes a lot of determination and focus. The Winetech team feel very strongly about management of vineyards and have gone through a great deal of effort to educate and hold discussions around this topic, but there seems to be two schools of thought within the wine industry; Some folk seem to think it enhances the wine flavour, while others feel that it only cripples quality and the longevity of the vine. So in my quest to know more I ended up at the proverbial door of Jaco Engelbrecht, a consulting viticulturist, whose passion on this topic knows no end.

Jaco says:

Why do some farmers say that Leafroll in vineyards produces good wine?
They say that because of ignorance. We don't have a viticulture driven culture but a winemaker culture. Leafroll affects production which affects the farmers, bottom line. Not all farmers have the money to rip out all the infected vines so they use this as a marketing spin in their favour.  

Why is the progress so slow and how can we measure improvement going forward?
The protocol for getting rid of leafroll was rolled out by Prof Gerhard Pietersen in 2008. Nine years later only a handful of wineries are proactive about leafroll eradication and showing success, namely Creation Wines, Vergelegen, Delaire Graff, Rupert and Rothschild and DGB. It's simply not enough. Rupert & Rothschild farmers will be encouraged to sign up to my leafroll protocol programme. Each year every farmer has to submit the number of vines that they have identified and marked as being infected and in September they have to submit the number of vines that they have replaced. These figures will be published on my website and the farmers will receive a certificate. This is a measurable way to say we are trying to do something about leafroll virus. It's about visible results, not media results.

How to measure the success of the program
You need to plant for the future, for the next generation.

Break it down to two main objectives:
1. Control Strategy - which is managing mealy bug by introducing biological control to control mealy bug i.e. ladybirds, wasps. It's a mind shift in farming culture.
2. Replacement Strategy - which is managing mealy bug AND replacing the vines. What this means is instead of ripping out your whole vineyard which could mean crippling your bank account we suggest the affected farmer starts a system of only pulling out a percentage per year of 20% (maximum).
The key is to get your vines productive and have them healthy in their 20’s, 30’s and older.

I asked Jaco why is he so passionate about this project to the point where he shows his annoyance rather openly towards ignorant parties. His reply to me: “This is the only way to ensure change. To be annoyed, to stand your ground and to live for this cause whole-heartedly.”

To know more about Jaco’s grapevine leafroll eradication program, click here