WEATHER BASED GRAPE ADVISORY

II. Water Management

 

a. Number of days after fruit pruning: 125

b. Expected Pan evaporation: 4-5 mm

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.       During Berry development stage till harvesting, apply irrigation through drip @ 6800- 8500 L/ acre/ day. 

Nutrient management

Berry Development stage:

1.      After Berry setting, apply 15 kg 12-61-0/acre in 2-3 splits. 

2.      If the berry size is from 2-4mm, spray calcium @ 2g Calcium Chloride or 0.5 g Ca chelate per litre.  Target sprays immediately after GA application (preferably next day) for better absorption.

3.      If the berry size is from 5-8mm, spray calcium & 2g Calcium Chloride or 0.5 g Ca chelate per litre.  Target sprays immediately after GA application (preferably next day) for better absorption.

4.      Apply magnesium sulphate through drip @ 10kg/acre from 8-10mm berry size.

5.      Foliar spray of sulphate of potash @ 3g/acre at 8-10mm berry size.

6.      After 8-10 mm berry size, start application of nitrogen in the form of ammonium sulphate @ 25kg /acre in 4 splits in calcareous soil and as urea @ 15 kg/acre in other soils in 3 splits.  Follow this up with Sulphate of potash or 0-0-50 @ 25 kg/ acre in 3-4 splits for next two weeks.

7.      If soils are calcareous, then apply zinc sulphate and ferrous sulphate @ 5-10 kg/acre at 65-70 days after pruning.

8.      Possibility of powdery mildew infection.  Build up potassium levels in grapevine either through foliar spray @4-5 gm SOP/L and drip @ 15 kg SOP/L if not applied since last 20 days.

Ripening to Harvest stage:

1.      Apply Sulphate of potash or 0-0-50 @ 25 kg/ acre in 3-4 splits for next two weeks.  Total potassium application (SOP) should be approx. 60 kg/acre during this stage.  Follow this up with Magnesium sulphate @ 10 kg/acre in two splits. 

2.      Spray Magnesium sulphate  and potassium sulphate @ 4g/L in calcareous soil.

3.      Possibility of powdery mildew infection.  Build up potassium levels in grapevine either through foliar spray @4-5 gm SOP/L and drip @ 15 kg SOP/L if not applied since last 20 days.

4.      Manage canopy for adequate sunlight and air movement within the canopy for avoiding/ minimizing problems of berry cracking.

5.      In early maturing and coloured varieties with possible reduction in temperature, possibility of berry cracking/ cracking of berries near the pedicel can be there.  If the harvesting is scheduled with in 30 days, do not go in for application of boron and calcium.  The application should be subject to deficiencies observed in the vineyard.  Focus on canopy density and regulate accordingly.  If cracking is there, then control secondary infections (disease and fruit flies).

III. Canopy Management

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

1.      In case of late pruned vineyard, berry thinning should be completed on priority. Number of berries per bunch should be based on the variety and the purpose (local, export and raisin, etc.)

2.      With the change in weather, powdery mildew incidence may get increased. Open canopy can be the best option.

3.      Arrangement of shoots on foliage wire and removal of 2-3 basal leaf on a shoot will help to reduce the microclimate.

4.      Bunch load management in case of colour varieties is important. To avoid delay in colour development, minimum bunch load to be maintained. 

5.      The grape bunches at the stage of veraison, should be placed under the canopy to maintain uniformity in bunch colour.

6.      Elongated varieties in the market are preferred when the TSS is higher. To achieve, the leaf around the grape bunch needs to be removed. This will help in obtaining yellow colour of grape berries having higher TSS.

7.      The preparation for re-cut in newly grafted vines to be initiated. Opening of trench (size: 2 feet wide and 3–4-inch depth) and application of FYM along with recommended dose of fertilizer will help for vegetative growth after the re-cut is taken.

8.      The re-cut of grafted vines should be taken only after the minimum temperature in the vineyard starts rising above 15⁰C.

9.      Application of hydrogen cyanamide @ 40 ml/L water along with Mancozeb @ 3g/L water can be used for bud sprouting.

10.  The cutting of shoot above graft joint with uniform diameter and height should be maintained for framework development.

11.  With the increase in day temperature, the water requirement of grapevine will increase. Considering the berry development stage and temperature, the management practices like use of mulch, irrigation during evening or early morning to be taken up.

 

IV. Disease management

 

Application of Trichoderma @ 2-3ml /L and Ampelomyces quisqualis @ 5ml/L should be done at an interval of 7-10 days to all vines for powdery mildew control. If there is a moderate incidence of powdery mildew, application of sulphur @ 2-2.5g/L may be given. Prior to harvest two sprays

of Bacillus subtilis may be given which will not only control powdery mildew but will also help in reduction of pesticide residues.

 

 

V. Insect and Mite management

Growth Stage: Veraison to post veraison stage after October pruning

 

Mealybug and mites population may be noticed due to favourable weather conditions.

Buprofezin 25 SC @ 1.25 ml per litre water (PHI 65 days) or spirotetramat 15.31 OD @ 280 ml per acre (PHI 60 days) are effective against mealybugs. If PHI with above insecticides is not available, then spot plant wash with trisiloxane polyether surfactant @ 0.3 ml per litre water with 10-12 litre water per plant to remove mealybug and honeydew from plant and bunches in the field can be given followed by wash with water.

Mite infestation may increase in most of the grape areas. Sulphur 80 WDG @ 1.5-2.0 g/L or Abamectin 1.9 EC @ 0.75 ml/L (PHI 30 days) or Bifenazate 22.6 SC @ 0.5 ml/L (PHI 30 days) water may be applied if mite infestation is observed.

All the cracked/damaged berries should be removed from the grape bunches. These berries should be destroyed by burying them minimum two feet deep in the ground away from the vineyards. It will reduce the scavenging fly population in the vineyard. These cracked berries can act as a good attractant for these scavenging flies. To make a trap, take a container with small holes at sides and put cracked berries inside it. Cover the mouth of the container with inverted paper-cone keeping a small hole at the bottom for fruit flies to enter. Hang these traps outside the vineyards. The berry cracking of grapes should be managed by following suitable viticultural practices.

Remove excess shoot growth to manage thrips. If pesticide application is necessary, then abamectin given for the management of mites will also control thrips.