
Published on 30 January 2025
Ing. Wolfgang Renner
Cordon training with cone pruning: preventive measure against late frost?
The establishment of cordon training with tenoning has three main objectives:
- Reduction of Esca through pruning with few wounds
- Labour savings through partial mechanisation of pruning (pre-cutting)
- Reduction of damage caused by late frosts
Since the 2013 growing season, the flat arch training (Guyot) and pruning systems have been compared for eight different grape varieties at two locations in the Haidegg research centre.
Cordon training with pruning involves developing a cordon and five to seven cones from old wood, depending on the distance between the canes. In the course of pruning, each cone is cut back to a two-eye cone, leaving a total of 10 to 14 eyes per vine. In winter, only a preliminary pruning to a length of four to six eyes is carried out - ideally with a mechanical pruner. The exact main pruning is only carried out after bud break. Due to apical dominance, the base eyes of the one-year-old wood are inhibited from budding and sprouting in the upper area. This can delay the budding of the base eyes by one to two weeks and perhaps minimise the risk of late frost? The heavy late frost in April this year offered the opportunity to investigate this question in more detail. The varieties most affected were Pinot Blanc, Welschriesling and Blauer Wildbacher. Here, significantly fewer frozen main shoots were actually observed in the pruning system. A shoot count for the Pinot Blanc variety also revealed a significantly higher number than for the control variant (flat arch). Grape counts shortly before the harvest also showed significantly higher numbers in the Welschriesling with cone pruning (13 grapes per vine) compared to 6 grapes with flat arch training! In order not to draw any premature conclusions, however, the definitive harvest results for this year must first be awaited!
In general, correct foliage work does not result in a thicket of foliage with the pruning system. On the contrary, the summer shoots from the cones grow more upright into the lowest wire pairs, the grape zone remains looser and better ventilated until the harvest. There are practically no differences in botrytis infestation.
In addition to many other questions, the question of the behaviour of eye fertility and, as a consequence, the yield of the stock is a central one! It is known that there are major varietal differences here. After several years of testing, it can be stated that the Morillon and Blauer Wildbacher varieties reacted more sensitively and that yields on the vine declined by 15 to 45%.
Mechanical pruning in vineyards with lateral hail nets poses a challenge, as it is very difficult or impossible to carry out in winter when the nets are rolled up. This problem can be solved by reversing the hail net system. The nets are fixed at the bottom and attached to the upper part of the foliage wall with carabiners. In autumn, after the harvest, the net is simply rolled down. During foliage work, the carabiners are unhooked, the net is rolled down or simply dropped down.
By using the mechanical pre-cutter, a labour saving of 40-60% can be expected for cutting, removing and binding work with the pivot cutting system compared to sheet cutting. However, for the initial foliage work (breaking out), around 8 additional working hours per hectare must be calculated for the pivot cut.