WEATHER BASED GRAPE ADVISORY

II. Water management

             a. Number of days after foundation pruning: 10

           b. Expected Pan evaporation: -7.5- 9

Amount of irrigation advised:

a.       In case the soil is under wapsa (field capacity) condition, donot irrigate the vineyard.

b.      Practice mulching to keep the bunds moistened. This will reduce the salinity build up in the root zone due to evaporation of the moisture from the surface of the bund.

c.       After foundation pruning, during shoot growth stage, apply 12,750 – 15,300 L/acre per day of irrigation water.  If EC of the irrigation water is less than 1 dS/m, then apply 10,200 – 12,300 L/acre per day.

d.      In case vigour is more than desired, then reduce irrigation water application to 6,400 – 7,600 L/ acre.  Still if you are not able to control the vigour, stop irrigation till such time growth is controlled.

e.       Cover the cordons of the pruned vines with shadenet, if available, for uniform sprouting as well as reducing the irrigation water needs by 20-25 %.  Shadenet coverage will reduce the temperature impact on the cordons.  However, remove shadenet after 3-5 leaf stage.  If shadenet is not available, spray the cordons with water during the peak heat period i.e. 2-3 pm to reduce the heat effect on the buds.

f.       In case there is probability of less irrigation water availability, then flood the bund (not whole vineyard) at pruning and mulch the bunds.  Flooding the bund will reduce the accumulated salt load in the root zone and mulching will reduce the evaporation of water from soil surface.  Thus, this will reduce the salt load in the soil and at the same time saturate the soil leading to proper sprouting.  Further, in case less irrigation water is available still the newly emerging shoots will not be damaged due to salinity.

g.      During fruit bud differentiation stage, shoot vigour to be controlled and hence, the irrigation water applied should be from 5000 to 6000 L/ acre/ day.

h.      For fruit bud differentiation stage, stress needs to be given. In clayey soil as the water holding capacity is higher, please note that stress needs to be imposed early else fruitfulness will be affected.

 Soil and Nutrient management

Rest Period

            After the harvest of grapes, vine reserves are exhausted.  After foundation pruning, till photosynthetically active leaves are formed, it is the vine reserves that contribute to the growth and development of the vines. Hence, following is advised:

1.      Provide only need based irrigation to protect the existing leaves from drying and also contribute towards increasing the reserves of the vines through photosynthetic activity.  The quantum of irrigation water applied should be approx. 5000 – 6000 L/ acre, once in a week.  Care should be taken to reduce/stop the water in case new growth is observed on the shoot. 

2.      Apply 10-15 kg urea, 25-30 kg SSP and 10-15 kg Sulphate of Potash per acre every 15-20 days till foundation pruning is not done. 

3.      Flooding the vineyard is not advised as it will lead to wastage of water.  Concentrate irrigation water application in the root zone only.

Foundation pruning:

1.      If planning for foundation pruning in next 10- 15 days, it is advised to get soil and water analysed for planning nutrient and water application schedule for foundation pruning season.

2.      If soils are calcareous in nature, then apply 50 kg/acre sulphur between the vines in the soil. The sulphur should be properly mixed in the soil for improving its efficacy in taking care of calcium carbonates.  Mixing of sulphur with FYM/ compost further improves its efficacy.

3.      The vineyards where sodicity problems are there, apply gypsum to the soil for removal of sodium from the soil exchange complex.  In case of calcareous soils, use sulphur for similar purpose.

4.      Shoot growth stage:

1.    Apply 50 kg urea/ acre in 5-6 splits after sprouting.  In calcareous soils, donot apply urea, instead use Ammonium sulphate @ 85 kg/acre in atleast 7-8 splits from sprouting onwards.

2.    In case of vigorous growth of shoots, stop nitrogen application and wait for the growth to stabilize before resuming nitrogen application.  If still the growth continues, then reduce irrigation.  Then resume when growth is maintained at desired level.

3.    Based upon soil test value, apply Zinc sulphate @10 kg/acre along with Ferrous sulphate @10kg/acre followed by Magnesium sulphate @15kg/acre in atleast 2 splits from 5-7 leaf stage onwards. Boron application should be strictly based upon soil and petiole test.

4.    In calcareous soils, spray magnesium sulphate and potassium sulphate @2 gm each/ L during active growing stage.

5.    Possibility of leaf curling, check the leaf margins, if slight to more yellow, possibility of potassium deficiency.  Foliar spray of SOP @ 3g/L followed by fertigation of 20-25 kg SOP/acre in 2 to 3 splits.

Fruit bud differentiation stage

1.        Based upon soil test values, apply 20 – 25 kg/ acre phosphoric acid or 150 kg/ acre SSP in case the soils are deficient in phosphorus.  Phosphoric acid application is desirable in calcareous soils. Donot apply beyond this until and unless the soil and petiole tests show low phosphorus availability.

2.        Donot apply any water soluble fertilizer having nitrogen.

3.        At 45 DAP, perform petiole test to know the nutrient content of the vines.  The petioles should be collected from 5th leaf from the base of the shoot even counting the leaves that have been removed.

4.        Apply Magnesium sulphate @ 15kg/ acre in atleast 2 splits from 45 to 55 DAP.

5.        In calcareous soils, spray magnesium sulphate and potassium sulphate @ 3 gm each/ L once only during 45 to 55 DAP.

6.        Keep a close watch on the development of leaf blackening symptoms if irrigation water contains sodium more than 100ppm.

7.        Possibility of leaf curling, check the leaf margins, if slight to more yellow, possibility of potassium deficiency.  Foliar spray of SOP @ 3-4g/L followed by fertigation of 20-25 kg SOP/acre in 2 to 3 splits.

III. Canopy Management

Based on the weather data and growth stages, following suggestions are offered for vineyard management.

A)    Old vineyard:

1.      The recent rainfall in different grape growing regions has reduced the temperature and increased the relative humidity in the grape vineyard.

2.      The increased humidity will be available for short period. However, it will help for faster and early bud sprouting.

3.      Covering the cordons with shade nets will help to reduce the temperature in vineyard and increase relative humidity that will support for early and unform bud sprout. In addition, it will control dead arm formation in future.

4.      In the pruned vineyard, the use of hydrogen cyanamide is must. This will help to enhance the sprouting. The concentration can be 20-25 ml per litre water.

5.      Under the condition of dead arms on the cordon, the last season cane can be used for developing new cordon.

6.      Use of sulphur in the root zone is necessary to control the problems of calcium carbonate in the vineyard.

7.      Immediately after the trench opening, it should be filled with FYM, recommended dose of nutrients and covered to avoid the root damage. Exposure of roots to sunlight for longer period will damage the root cells. This will also lead to dead arms on the cordons.

B)    New vineyard:

1)      After the re-cut, pasting of hydrogen cyanamide is done on 3-4 buds thereby sprouting all these buds thus converting into new shoots.

2)      After the bud sprouting, only straight and fast-growing shoot to be selected for trunk development. The selected shoot to be tied to bamboo with sutali.

3)      While developing the trunk, stop and go method to be followed. The growing shoot to be pinched at 7-8 leaf stage when it is at 10-11 leaf.

4)      The side shoots on the new growth are then pinched at 3-4 leaf and the upper shoot to be tied for next instalment of cordon.

IV. Disease management

As the temperature is high and pruning is in progress in many areas, it is advised not to use any fungicide during this time as the probability of disease is almost nil. Spraying of water in the cordons is advisable.

V. Insect and Mite management

1.    Preventive spot plant wash with buprofezin 25 SC @ 1.25 ml per litre water with 1.5-2.0 litre water per plant just after pruning.

2.    Give preventive spray of imidacloprid 17.8 SL @ 0.4 ml per litre water at the time of bud sprouting after April pruning to manage flea beetle and mealybug shoot malformation.

3.    For flea beetle management, spray imidacloprid 17.8 SL @ 0.4 ml per litre or fipronil 80 WG @ 0.06 g per litre or lambda cyhalothrin 4.9 CS @ 0.5 ml per litre water during early morning hours or late evening. If that is not found sufficient to manage flea beetle, give soil drenching of imidacloprid 17.8 SL @ 1.5 ml per vine also.

4.    For thrips management in new vineyards after recut or new shoot growth after April pruning, give regular applications of effective insecticides such as spinosad 45 SC @ 0.25 ml/l, spinetoram 11.7 SC @ 0.3 ml/l, cyantraniliprole 10 OD @ 0.7 ml/l, emamectin benzoate 5 SG @ 0.22g/l or fipronil 80 WG @ 0.0625 g/l water when thrips population is 5 per shoot or above.