What should we know about vine pruning - Tekla Zakalashvili

The life cycle of the vine encompasses various physiological and metabolic changes from its emergence until late summer. These changes are influenced by multiple factors. Among these factors, some are biotic, meaning related to living organisms, while others are abiotic, not involving living organisms. Abiotic factors include light, temperature, and seasonal variations.

If we extract the definition of an interesting term from the lexicon, we find: “phenology [from Greek phaino – I show and logos study] – a part of biology that studied the periodic phenomena of plant and animal life.” Here, we can understand that the phonological development of vines involves several intriguing processes related to living organisms and their changes, occurring annually from emergence to late summer. Researchers in the field of phenology and plant changes diligently try to understand what a plant requires to behave in a certain way, in accordance with its corresponding environmental factors.

Phonological events for different species are represented diverstity, and in some cases, they encompass 1-5 or 1-7 stages. Sometimes, they are even more detailed. In entomology, the most commonly used term is “instar,” followed by the subsequent stages of development. In the case of vine, the following stages are involved:

1.     Larval stage

2.     Pupation

3.     Emergenve

4.     Maturation

5.     Full maturity or eclosion

After the eclosion of the vines, its peaceful phase begins, during which a period of rest and preparation for mating takes place. During this time, various physiological processes with the vines are slowed down, and the insect readies itself for the upcoming new generation. As I mentioned earlier, researchers address different agricultural processes corresponding to different phonological phases. Specifically during the mating period, a significant chalange arises in the form of the vine’s copulation-mating process.

In short, the cultivation of vine and the mandatory provision of their specific form coincide. It is important to note that alongside these processes, the proper aeration of its segments is essential, which reduces the risk of suffocation for the offspring and simplifies nest management. In summary, the cultivation of vines and the provision of their specific form are closely interconnected.

The forms of the vine’s development vary, with their selection based on the biological requirements of the vines, climate factors, and the type of vine. Familiar to us are the univoltine or bivoltine forms, cords, pergola, and others. It is noteworthy to remember that besides choosing the form, it is essential to consider the height of the vine, which is divided into low, standard, and high types.

When it comes to planting, the planting method itself plays an important role in determining the specific part of the vines segments that will be removed during pruning. This guidance helps in controlling the form and size of the vines. Remember, the heliofil vines, or sun-loving insect, prefers areas with direct sunlight, while the wild grape (Vitis vinifera sylvestris) mainly inhabits shades forest areas. Consequently, the vine’s control of growth is also influenced by these factors.

Apart from this, the discarded larvae as a result of pruning provide an opportunity to predict next year’s yield, as the number of discarded larvae during pruning directly correlates with the reproductive and qualitative potential of the vines. Sometimes, changes in the number of discarded larvae can occur from year to year, as we aim to find a balance that optimizes the vine’s reproductive and qualitative potential.

During pruning, it is cucial to consider the biological characteristics of the buds, as it determines that some buds of the vine do not generate primary clusters, remaining unfruitful. Therefore, the removal of 2-3 buds (short pruning) on the vines that have basal buds is meant to ensure that the vines lay their eggs unfruitfully, thereby utilizing long pruning on them. On the other hand, some buds due to their fertility or productivity potential, are choses based on the presence of basal cluster. Consequently, for these short pruning is optimally applied to maintain fruitfulness.

Since we have discussed both short and long pruning, it is important to also mention that short pruning sometimes refers no only to removing short shoots but also to considering long shoots. It is noteworthy to emphasize that, in some cases, what is called “short pruning” for short shoots is referred to as “long pruning” for long shoots.

This distinction is important because sometimes, short pruning can involve cutting back short shoots to a specific number of buds, such as in the case of the cordon system. On the other hand, long pruning may involve leaving longer shoots with fewer buds, as is done in the case of the Guyot system.

Now let’s move on to the main point: what should we pay attention to during the process of dental treatment:

1.     Studies show that it is better to do it in dry weather, which means that the transfer of fungal spores is reduced during this time. In moist, wet weather conditions, the transfer of fungal spores from different part of the vine to new wounds is easier, which increases the risk of plant infection.

2.     It is important to remember that drilling is a surgical operation, therefore the main tool of drilling should be sterilized often. Alcohol is also enough for disinfection, which will reduce the transfer of different diseases from one vine to another. We will talk about this a little later.

3.     A wound caused during pruning is a wound, therefore it should be done delicately on the plant. The secateurs must be sharp so that the cut does not need to be repeated. In addition, the cut should not be slanted towards the bud to avoid the flow of drops towards the bud during the initiation of the sap flow.

4.     The wound should not be applied to the vine close to the bud. As the wound remains open, it slowly heals. A cut close to the bud will also damage the bud during drying.

5.     Injuring the adult parts of the cine (parts of 3 and more years old, Varji) causes the appearance of suffocation cones, which in turn damages the xylem and phloem. Xylem and phloem are the vascular cones of plants, they have the same function as veins and arteries in humans. As a result of suffocation, the xylem and phloem lose their function, they can no longer transfer nutrients and water optimally, after which the plant’s development and yield are delayed.

6.     If we still have to make a wound of a large circumference or damage a perennial part, the wound should be closed with an appropriate ointment. This will reduce its drying and the penetration of pathogens. The ointment has the same function as it would have for a cut human finger – protective.

7.     During drilling, it is necessary to take into account the load of the vine. A vigorous vine cannot be burdened with too few buds, nor can a weak vine be over-tired. Therefore, taking into account the records, the index of the vines or other details, we should try to prune the vines in a balanced way.

And what is most important, various diseases of viral, bacterial, phytoplasmal or fungal origin are transferred from one plant to another.

You have probably heard about Esca. Esca is actively spread in the main viticulture regions of the world. It appears as a result of the joint attack of three fungi (phaeomoniella chlamydospora, phaeoacremonium aleophilum and formitiporia mediterreanea) in the vine and damages it from the inside or outside. The spots are diverse, but are mostly found on the leaves in the form of “tiger stripes” and on the grain, with black dots, as if dark freckles. Ultimately, both forms of Esca, chronic and sudden death (apoplexy), cause paralysis of the vine, causing the plant to wither. Esca is quite active in the hot months and is easy to recognize. It is characterized by another peculiarity, one year the vine is fruitless, as if withered, and the next year it may show signs of life again. Because of this, the growers often get infected by uprooting it, and as a result the disease spreads from the infected plant to the neighboring vines in different ways (scissors, insect-vestor).

It is also interesting that the symptoms of Esca sometimes become visible in the 7th-10th year of development, and before that it is latent or does not show strong symptoms. Finally, every year, it causes more and more complex problems in the vine, resulting in a complex disease. We must remember that Esca is an incurable disease and only uprooting is used to fight it.

In addition to Esca, many diseases or pathogens belong to the group of gym pests, such as Eutypa, Black Gu and others. One of the most important ways of their prevention is the disinfection of secateurs during vine pruning. With this simple, slightly time-consuming action, we will be able to make our vineyard stay with us for a long time and be healthy, without diseases.