2.3.1.c How is debudding conducted?

How many fruiting buds are there on the vine?

Most of the fruiting buds are found on the current year's pruning wood (spurs and/or the vine's canes). It is possible to have buds develop, sometimes that are fruit-bearing, on the old wood but this cannot be counted in the load.

To count the total bud number, it is sufficient to count the number of "winter buds" present on the vine's canes and/or the spur. Once the number of buds has been counted, it is important to take into account the vine's vigour before debudding.
Another technique does not require counting of the buds, but rather the keeping of a sufficient number of buds, and removal of the excess.

Is this consistent with desired yields?

To answer this question, it is necessary to assess the vine's vigour. Vigour can be expressed in several ways in a vine and cannot be identified in the same way for the entire vineyard. However, certain criteria can be easily identified by the winegrower at the plot level. The length and the diameter of the wood are important indicators of a vine's vigour.

The longer the wood and the larger the diameter, the more vigorous the vine. Another criterion is leaf expression. Production of herbaceous parts of any kind is directly proportional to vigour.
However, this criterion is more difficult to control with the implementation of canopy management early in the season. To remedy this, measurements in the vineyard give reliable indications of vegetative expression and vigour, such as NDVI sensors or lasers that can map a zone, a plot, a block of plots or an entire vineyard. The weighing of pruning wood and measurements of branch growth speed are also methods of assessing vine vigour.

NDVI

If vines are vigorous, it is advisable to leave more fruiting buds which will act as a reserve for the vine's resources. When insufficient buds are left on a vigorous vine, the vine has tremendous potential to develop a substantial and unwanted quantity of other vegetative parts such as supernumerary buds and shoots. An expert pruner will be able to visually assess the relative vigour of each vine and adapt the load accordingly. For example, a vigorous vine will be able to bring more bunches to maturity than a less vigorous vine and will therefore be able to support more buds.

Having determined the vine's vigour, the winegrower can leave a precise number of buds depending on the desired yield. On average, a fruiting bud will produce a branch with one to two bunches. Depending on the desired number of bunches per vine, the winegrower can determine the approximate number of buds to leave. It is very important, when possible, to assess and determine the load on the basis of each vine. It is not advisable to leave a maximum of buds and then remove the bunches later by thinning. This is a corrective practice that entails a high risk for the vine's survival.

What if the buds are too close together or too numerous on a cane?

The buds may be too close to each other, this occurs primarily when the distances between nodes are too short. It is also possible that there are too many buds on the same cane, both cases can cause problems. Limiting the number of buds is essential to harmonize and regulate production, vigour and crowding. In this case, it is possible to remove a bud in order to create an empty space, also known as a "window", which will reduce this potential crowding. Reducing crowding helps to maintain the health of the vineyard.