New defences against an old enemy: how viticultural research is prioritising prevention to protect our vineyards
To ensure the South African wine industry continues to produce high-quality wines for future generations, those in the trade must stay abreast of the ever-changing business and science of wine and viticulture. As the country’s largest independent wine specialist, Vinimark takes this leadership responsibility seriously, often engaging with researchers and experts to cultivate an in-depth understanding of every aspect of the profession.
‘From climate change and shifting consumer demand to Eskom’s unreliable power supply and the rocky resilience of our supply chain, obstacles to South African wine production are plentiful and ongoing,’ says Vinimark Production Manager, Rudiger Gretschel. ‘To work towards a prosperous future, we have to pay attention to the finer details and seek out the insights of subject matter experts to guide our decision-making.’
While new challenges continue to emerge in 2024, some stretch as far back as the 19th century. One such threat is a small but lethal insect called grape phylloxera, which nearly wiped out vineyards across the world – and it could strike again. While this might sound like something out of a science fiction movie, the problem is very real, and the repercussions of leaving the problem unchecked are frightening.
Imagine a vine’s roots being nibbled away, their lifeblood intercepted by tiny invaders. Phylloxera is an almost-invisible aphid-like insect that lives underground and feeds on grapevine roots, causing massive damage. ‘Phylloxera’s saliva induces the growth of a gall on the roots, intercepting nutrients meant for the plant. This compromises the entire root system, eventually killing the vine,’ says Elleunorah Allsopp, a leading entomologist and Senior Researcher from the Viticulture Research Farm in Stellenbosch.
Allsopp shared her in-depth insights as a guest on an episode of the Vinimark podcast hosted by Jono le Feuvre. The podcast series is an initiative facilitating conversations along the rough edges of wine commerce, cellar mastery, marketing, trends and science, with each episode featuring a guest with specialised knowledge. Allsopp has dedicated 34 years of her career to the study of insects, and more specifically the impact of pests on agriculture. Her recent work at the Viticulture Research Farm centres around studying the threat of phylloxera and how to overcome the complex challenges it presents to winemakers.
To understand the gravity of the pest’s possible resurgence, one must take a look into its past. Although phylloxera originated from the southeastern US, particularly around the Mississippi Basin, its effect spread across the winemaking world in the 1850s. European growers brought American grapevines to Europe to breed disease-resistant plants without the knowledge that these vines carried phylloxera larvae. Once introduced, the larvae spread rapidly from France, and devastated European grapevines which had no natural resistance to the pest.
This tiny pest was responsible for one of the most significant agricultural disasters in history. Estates that had thrived for centuries faced ruin. ‘The image of once-lush vineyards reduced to barren fields is a haunting reminder of the devastation phylloxera can cause and a reminder to our producers to keep a watchful eye on their vines,’ says Gretschel.
In South Africa, the earliest recorded instance of grafting to combat phylloxera was in the late 19th century, where vineyards in Constantia adopted a practice that was already saving the international wine industry and allowing vineyards to recover and flourish. Constantia’s producers began grafting European grapevines onto phylloxera-resistant American rootstocks, leading to a resurgence in our wine production.
Despite the historical devastation caused by phylloxera, many viticulturists today think the problem is over. They believe that because we use resistant rootstocks, phylloxera can’t cause any more harm. However, recent surveys show this isn’t true. ‘We have found phylloxera in very small numbers on supposedly resistant rootstocks throughout South Africa. They didn’t cause significant economic damage, but their presence is a warning sign,’ says Allsopp.
Climate change continues to have an impact on the wine industry, and in this particular instance, it is also making things worse. Changes in rainfall patterns and increased temperatures are stressing vineyards, bringing a host of new vulnerabilities, including susceptibility to an outbreak of phylloxera.
‘South Africa’s wine industry is crucial for the country’s economy,’ says Gretschel. ‘If phylloxera were to spread again, it could severely impact wine exports, especially to major markets like the UK and Germany.’ These countries apply strict import regulations to affected areas today. Consider the shock waves through the industry if vineyards were once again laid to waste, affecting jobs, tourism, and the very fabric of South African wine culture.
To prevent another phylloxera disaster jeopardising the future of South African wine, the industry needs to act: modern vintners must adopt a proactive approach. Along with regular monitoring, better nursery practices, and continuous education, keeping up to date with global best practices is essential to sustaining a healthy industry.
Chile is the only major wine-producing country that has never experienced a phylloxera outbreak, thanks to its isolation and stringent biosecurity measures. ‘Chile’s climate, vineyard locations, and soil types have contributed to its phylloxera-free status. Its strict biosecurity measures have also prevented its introduction,’ says Allsopp.
This example shows how important it is to have strong preventive measures and vigilant monitoring in place. Some Vinimark Brand Partners offer key case studies to illustrate sustainable practices which include the motivated prevention of another outbreak.
Reyneke is already taking steps by using environmentally-friendly methods such as cover crops and reduced chemical inputs to maintain vine health and reduce the risk of phylloxera. Systemic insecticides can kill phylloxera, but they’re controversial because of their environmental impact; they can harm pollinators, which are vital for many crops. Reyneke’s approach shows that preventative measures must form part of an overall environmentally-friendly strategy which prioritises sustainability.
Ernie Els Wines is another success story. It has mitigated phylloxera risk through a combination of resistant rootstocks and watchfulness, ensuring its vineyards remain healthy and productive. The South African government is also stepping up, allocating funds for vineyard health initiatives, including grants for phylloxera-resistant rootstock development.
Vineyards under stress from drought or poor soil conditions must be extra attentive to possible phylloxera infestations. ‘The level of resistance or tolerance in our rootstocks depends on their vigour. If something happens and your rootstock is no longer growing well, phylloxera can gain the upper hand,’ says Allsopp.
Enforcing strict nursery protocols and ensuring better communication between growers and nurseries must also be emphasised. Phylloxera spreads primarily through the transport of infested vines, therefore ‘growers must insist nurseries supply phylloxera-free material,’ says Allsopp.
A promising area of research is developing new rootstocks with enhanced resistance to phylloxera and other stresses. Advances in genetic engineering and breeding techniques could lead to rootstocks that are more robust and less susceptible to pests and diseases. However, these innovations require time and investment. While researchers remain focused on staying ahead of phylloxera and other threats, the responsibility falls to producers to engage the viticultural expertise and insights of these professionals.
The problem is complex and resistant rootstocks are not a perfect solution. Says Allsopp, ‘The problem is that our resistant rootstocks are often hybrids, and their resistance is not absolute. Phylloxera can still exist in small numbers on these rootstocks, waiting for an opportunity to thrive.’
Many vineyard managers and workers may still not fully understand the threat or recognise the signs of an infestation. Knowledge is power and those involved in every level of viticulture must receive ongoing education and training to support an understanding of the risks of phylloxera and the complexities of pest management and vineyard health as a whole.
This can be achieved through workshops, seminars and accessible informational resources for those in the industry. Wines of South Africa (WOSA) is leading consumer awareness initiatives to highlight the importance of supporting vineyards that adopt sustainable and phylloxera-resistant practices, and Vinimark’s podcast on the topic is available on Spotify or via https://vinimark.co.za/podcasts/podcast-episode-elleunorah-Allsoppp-on-phylloxera
Additionally, VinPro, an organisation that supports South African wine producers, offers workshops and resources to educate vineyard managers and workers about phylloxera identification and management.
With increasing pressures from climate change, economic fluctuations and evolving consumer preferences, the added threat of phylloxera cannot be ignored. By taking it seriously and implementing comprehensive management strategies, including dynamic measures, vigilant monitoring and sustainable practices, the South African wine industry can prevent history from repeating itself, and continue its legacy for centuries to come.
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