Vine Stress & Poor Nutrition.
Over the last three weeks many vineyards have not been growing through the wet weather. Also they have shown symptoms of nutrient deficiency including iron as shown by pale leaves (above).
The reason for this slow growth and poor nutrition is a lack of root growth.
Talking with Stoller USA agronomist - Guillermo de la Borda he offer the following advice.
As a rough rule of thumb if your vines shoots are not growing neither are your vine roots. Vine roots pick up the nutrients for growth at this time of the year.
Several stress events which limited vine growth have occurred in including;
- Hail damage
- Wind damage
- Cold soils.
All of these stresses upset the vines hormone production and normal growth. Waterlogging and cold soils slow down root growth. Physical damage including hail, wind and frost cause the plant hormone Ethylene to be produced. Ethylene interferes with the plants growth hormones Auxin, Cytokinin and Gibberellic Acid. With an imbalance of these growth hormones root growth is stunted, this in turn stunts shoot growth.
Many growers apply fertiliser to improve shoot growth, but without active root growth the vines will not pick up the fertiliser and growth will not improve.
The good news is, as vines experience good weather, they should grow out of this ‘stress damage’ and grow new roots on their own accord.
See Stoller's frost recovery programme here.