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Grape bunch Filage

Filage or "bunch shift" is a physiological phenomenon that occurs in table grapes and generates production losses that can reach 60-70% in losses. Productivity drops caused directly by bunch lost can become catastrophic in young trelis grape planted on invigorating rootstocks such as SaltCreek or Freedom, harvesting in the most extreme cases 6-8 bunches per plant.





What is the "Filage"?

The filage, also called “grape inflorescence reversal”, is a physiological problem characterized by an involution of the bunch or inflorescence in the phase of “visible bunches”, towards a structure similar to a tendril.


Obviously there are many theories regarding the origin and prevention of this problem. In this case, we will address in a very general way the most characteristic elements that favor filage and the general prevention strategy:


  • Excess nitrogen in the translocation phase that generates bad withering, therefore, unprotected buds and poor definition of bunches.

  • Very early applications of nitrogenous cyanamide that produce poor sprouting, therefore the clusters do not fully differentiate.

  • Uneven budding, with shoots fired in spring (high vigor and a high gibberellin/cytokinin ratio) which generates a sink effect towards the apex of the shoot.

  • Shoot/inflorescence competition, which translates into a poor redistribution of hormones, sugars and, above all, reserves towards the new cluster, preventing its final definition.

Prevention measures

The measures and prevention of this phenomenon mainly point to the management of the outbreak and the canopy throughout the season, especially in the post-harvest or translocation phase. The idea is to aim to control the excess vigor and foliar mass that it generates: shading of chargers and buds, high levels of endogenous gibberellins in the plant, induction problems and finally bunch differentiation.


I recommend carrying out: bud fertility analysis, short pruning, defoliation, control nitrogen, favor good withering, favor high reserve levels, but not excessive, slightly delay the application of cyanamide to avoid very early budding (with cold and cloudy days), "support" the shoot in spring with foliar biostimulants with a high C ratio /N in order to supply the elements that the plant will not potentially generate to supply the final differentiation of the cluster that is exposed (marine algae, amino acids, zinc, reducing sugars, etc.) and finally the use of natural phytohormones of the cytokinin type in order to unbalance the gibberellins/cytokinins relationship and improve the termination of pre-flower clusters.


EXTRACT ARTICLE PUBLISHED IN PORTALFRUTICOLA.CL

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