It is a real surgery
"Wood diseases represent a major threat to the longevity and economic sustainability of vineyards”...
The annual economic impact, related to wood diseases, caused by replanting costs and loss of actual production amounts to 1,132 trillion euros (Hofstetter et al., 2012).
The impact of wood diseases is also considerable on the longevity of plants: According to a study by Baumgartner (et al. 2014), the incidence of plants showing symptoms of wood diseases, by the 15th year of production, can be as high as 75%.
Esca disease is caused by a complex of fungi that attack the woody structure of the plant. It manifests itself in its chronic form with the typical symptomatology of a tiger leaf and, internally, with spongy tissue typical of decay or, in its apoplectic form, with the immediate death of the plant.
When plants unfortunately show symptoms of chronic Esca or even apoplexy, they are usually destined for eradication.
Among the various wood diseases that can attack vines, esca appears to be among the oldest and most relevant
The most important of the cultural practices that lead to Esca disease is the pruning technique used
Among the cultural practices that lead to Esca infection, the most important appears to be the pruning technique used, as also suggested by the OIV (Vine Resolution No. 2/2006): a greater prevalence of Esca disease is found in those vineyards where the pruning technique involves large and frequent cuts on the plant with “head pruning” management or with “back-cuts” and trunking (Travadon et al., 2016).
“The fungi responsible for wood diseases attack and penetrate the plant through pruning wounds”
Thanks to the many sections of vine plants we have made over the years, it is possible to observe the internal structural consequences caused by managing plants with the head-pruning and back-cutting technique.
The desiccation cone caused by large pruning wounds creates a plug below which a wet area develops: here the disease degrades the wood, reducing it to a spongy, brittle mass.
“vine surgery is an actual surgical procedure through which decay that has attacked the woody structure of the plant is removed”…
It is a technique that we experimented first in France and then in Italy and which consists in removing the wood rot that forms under the wounds caused by incorrect pruning, precisely those through which the fungi penetrate and attack the wood, coming to compromise the integrity of the lymphatic system of the vine.
Specifically, we first select the plants that clearly exhibit chronic symptoms, then we conduct a careful external analysis of the plant: pruning wounds and structure condition, to understand where to begin to operate. We then proceed to remove the decay on all individuals showing symptoms.
“An alternative to uprooting, preserving the historical and productive value of vineyards”
Often, the spongy tissue (white decay) that needs to be surgically removed is located below the large pruning wounds. Once vine surgery is performed, removing the internal decay with accuracy, a rapid vegetative recovery of the plant is observed within a few weeks, with the disappearance of leaf symptoms.
“The plant thus cleaned up regains vigor, resumes fruiting and becomes fully productive again”.
technique and experimental evidence
10 years of experience, two experimental fields in Italy, about 3,000 operated plants show how from a productive point of view, plants subjected to vine surgery, with the same number of shoots on the fruiting head, reveal a slight decrease in production compared to healthy witness plants, during the year following the decay removal operation (probably related to a general lower vigor of the operated plants).
As early as the second year, the number of bounches per plant stabilizes at the same quantities as the healthy plants, ensuring the same level of production.
The economic advantages are many. These include reduced costs due to replacements and the chance to maintain a constant production level in the vineyard.
“Over 90% of the operated plants no longer show symptoms of Esca disease and recover their normal production level within two years”.
Vine surgery shows a consistent economic advantage over the common practice of uprooting and replanting symptomatic plants with young plants.
In comparison with what is shown for plants treated with vine surgery, from a production point of view, rooted cuttings up to the 5th year do not guarantee the same number of bounches as a healthy adult plant, leading to an important loss of production.
Considering the profit and loss account for a 5-year period based on the individual cost items of the two different operations (rooted cuttings, replacement operations, vine surgery, labor, fertilization and irrigation, materials and machinery, loss of production), the economic advantage derived from vine surgery is about 50% compared to the classic uprooting and replanting with rooted grafts (Considering one bottle per plant at a price of 10 euros/bottle).
“The economic advantage derived from dendrosurgery is about 50% compared to classic extirpation and replanting”.
Since 2010 we have been engaged in ongoing refinement of the surgery technique: in collaboration with Professor Denis Dubourdieu, we started studying the Bordeaux pruning systems and the methods of care and cleaning of infected plants in Sancerre on Sauvignon Blanc, a variety particularly sensitive to trunk diseases, where dendrosurgery was an agronomic practice used. Then, together with Dubourdieu we then set up an experimental campus in the Sauternes area (Bordeaux).
Since 2013, we have set up two other experimental camps in Italy (Franciacorta and Collio) where we surgery plants showing chronic symptoms of esca disease. These plants are monitored annually, collecting data on agronomic and production performances