The Primary Concerns For Vineyard Health
Vineyard health is influenced by a wide range of factors similar to ourselves: no one size fits all. In fact, human health is often associated with lineage, daily care and even how we are cared for in our developmental stages; this is no different for the vineyard. From the time the vine is grafted in the nursery to when it is no longer in production, health is the number one concern. This is how we maintain quality, yield, and sustainability. So it begs the question:
What are vintners struggling with most and how can they react to these challenges?
The primary concerns in modern grape growing are water security, pest management, and grapevine disease.
Water Security in the Vineyard
It is no secret that water has become increasingly scarce and the level of restriction on said water supply has become more intense. Water is as essential to the grapevine as it is to the human body. Water is applied to the soil surface where it will then be absorbed by the roots until it surges up the pipeline of the plant to the leaves due to a difference in water pressure. Water is drawn by leaves at the surface, where the open stomata are expressing transpiration. Now, the grapevine has a water deficit tolerance mechanism, closing its stomata in order to conserve water when necessary. Unfortunately, a prolonged closure will hinder photosynthesis, having various effects on plant health as seen in plant expression and berry composition.
Some of these adverse effects include:
- Restrictions on shoot growth
- droopy leaves
- Dried up tendrils
- leaf discoloration
- Decreased sugar in berries
- Weak yields
- Lack of nutrients
The best thing that vintners can do is invest in precision viticulture systems and focus on soil health to promote water holding capacity.
Pest Management in the Vineyard
In addition to water consumption, managing the micro-ecosystem greatly contributes to grapevine health. In the vineyard there are many pests, some are predatory and some are beneficial. Some of the beneficial creatures include lady-bugs and ants, as they are natural predators to pests that should be avoided in the vineyard like predatory thrips, aphids and mealybugs.
Thrips are a pest that have a rapidly growing population that causes damage to the vegetation. They can also cause scarring in the berries, which is a poor reflection of vineyard health. Aphids and mealybugs are similar in their damage technique of “sap-sucking.” Mealybugs are notorious for being vectors of disease, yet the industry has not achieved a solution to eradicating them in the vineyards. Mealybugs also introduce a level of contamination by producing honeydew which causes sooty mold and decreases plant vigor.
Disease in the Vineyard
As previously mentioned, mealybugs are vectors for viral diseases including the most common Grapevine Leafroll Virus (GLFaV) and Grapevine Red Blotch Disease (GVBaV).
GLFaV can also be contracted upon grafting in the nursery, highlighting the need for vintners to be involved with their nursery and equipped to detect unusual symptoms at early stages.
Symptoms of GLFaV are generally easy to spot as leaves will begin to curl and redden in the early stages of summer, this virus has proven to significantly decrease yield and quality by delaying sugar and pigmentation development. For this reason, it is important for vintners to do two things: understand if they have disease presence and understand if they have mealybug presence. Once the mealybug penetrates the vine, they become a vector and can increase spread.
In addition, vintners should be testing and adjusting their management based on what works in their region, grape variety and when the presence began.
GVBaV is not presently as common as GLFaV, but it has been reported regionally for several years across the United States.
Presence of GVBaV causes the veins of the leaves to redden, making it easier to distinguish GLBaV from GLFaV. GLFaV expresses more blotching and avoids the veins. When vintners are faced with GVBaV, they are encouraged to seek specialty help and will likely be guided to replant with consideration for susceptible varieties such as Chardonnay.
With this disease, a decrease in quality and yield will be apparent, but even more so in growth uniformity. As previously stated, being aware of spread is extremely important.
Vineyard health is attested to the above items, but also so much more. The best suggestion for aspiring vintners is to introduce precision viticulture to your vineyards, conduct regular testing on soil and plant tissue, utilize field scouting methods, stay up to date with validated solutions and ultimately find the best fit management for your operation.
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