WEATHER BASED GRAPE ADVISORY

WEATHER DATA FOR THE PREVAILING WEEK

Date of Fruit Pruning: 15/09/2022

Thursday (29/12//22)–Wednesday (04/01/2023)

Note: Above weather information is summary of weather forecasting given in following websites

https://www.wunderground.com/?cm_ven=cgi

https://imdagrimet.gov.in/weatherdata/BlockWindow.php

https://www.timeanddate.com/weather/india

ICAR-National Research Centre for Grapes does not claim accuracy of it.  

Water management (Dr. A.K. Upadhyay)

Pan evaporation: 3.5-5 mm

Amount of irrigation advised (Dr. A.K. Upadhyay):

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

2.      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.

3.      During Flowering to setting stage, apply irrigation through drip @ 2000 to 3400L/ acre/ day.  Further, in case vigour is more than desired, then reduce irrigation water application by half.

4.      During Berry development stage till harvesting, apply irrigation through drip @ 6000- 8500 L/ acre/ day. 

IV. Soil and Nutrient management (Dr. A.K. Upadhyay)

1.    In early maturing and coloured varieties with possible reduction in temperature, possibility of berry cracking/ cracking of berries near the pedicel cracking can be there.  If the harvesting is scheduled with in 30 days, do not go in for application of boron and calcium.  This will be waste of money and time.  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). 

2.    If SOP not applied, then apply 15 kg SOP and follow it up with SOP spray for building up the potassium levels in the vines. This will be especially beneficial during low temperature and rainy conditions.

Flowering to setting stage:

1.      Inflorescence necrosis could be a issue in dense canopy. Remove side shoots and reduce canopy to allow penetration of the sunlight for proper aeration.  Manage canopy for adequate sunlight and air movement within the canopy for avoiding/ minimizing problems of kooj (inflorescence necrosis).

2.      Apply 3-4 kg Phosphoric acid in two to three splits this week.  Remember that the pH of the irrigation water should be near 6.0.

3.      Petiole nutrient testing: At 70% capfall stage, petiole samples should be taken for nutrient analysis. The leaf opposite the bunch should be removed for sampling.

Berry Development stage:

1.      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.

2.      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.

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

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

5.      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.

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

7.      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.  Follow this up with Magnesium sulphate @ 10 kg/acre in two splits.  Spray Magnesium sulphate @ 4g/L in calcareous soil.

III. Requirement of growth regulators (Dr. S.D. Ramteke)

NIL

IV. Canopy Management (Dr. R.G.Somkuwar)

Growth Stage: Berry development stage to veraison after October pruning

1.      The minimum temperature in the vineyard is decreasing even upto 6 to 7 degree. This will make the imbalance of physiological activities of grape berries. The green pigment may change into pink color.  This is called pink berry.

2.      At present,  there is no solution for the control, but covering of individual bunch with newspapers will help to reduce the pink berry.

3.      Flood irrigation sometimes help in increasing the vineyard temperature.  However, avaibility will decide.

4.      Most of the time, growers are flooding the vineyard and then covering the bunches with newspaper. The change in vineyard weather may become more congenial for the development of powdery mildew.  

5.      Considering the above,  control of powdery mildew and mealy bugs before the bunch covering should be given priority. 

6.      In addition to the above,  spray of biologicals should be considered. 

7.      With the reduction in night temperature, the berry development may get hampered. To increase berry size, the grape growers are using more PGR and also the biostimulants available in the market.  This result in berry thickening, delay in dugar development and thus the vine goes into stress by delay in harvest. 

8.      To control the above situation,  loosening of bund to encourage aeration in the root zone should be given priority. 

9.      Application of phosphorus and recommended irrigation will help to increase berry size. 

10.  Use of excess PGR is resulting into knot on peduncle as well as on the pedicel. Hence, the use of  PGR should be as per the recommendation.

V. Disease management (Dr. Sujoy Saha)

Incidence of powdery mildew may be observed in many locations especially in berries. Application of hexaconazole or difenoconazole or tetraconazole or cyflufenamid or Fluopyram + tebuconazole or Fluxapyroxad+ Difenconazole will control powdery mildew. A new fungicide Polyoxin D zinc salt 5% SC @ 600ml/Ha will also give good results against powdery mildew. A tank mix of triazoles with potassium bicarbonate @5g/L will help in increasing the efficacy of the fungicides. One application of Ampelomyces quisqualis @5g/L or Bacillus subtilis @2g/L may be given for powdery mildew prevention. The bunch load needs to be maintained for proper coverage of fungicides. Use of sulphur @2.5-3g/L needs to be enhanced in between triazole sprays.  No mixing of fungicides and biocontrol agents should be done. The moisture condition in soil should be optimum to reduce plant stress and increase disease resistance.

VI.    Insect and Mite management. (Dr. D.S. Yadav)

Growth Stage: Berry development stage to veraison after October pruning

1.    Mealybug, thrips, black thrips, aphids, mites and caterpillar population may be noticed due to favourable weather conditions.

2.    Yellow sticky traps may be installed at canopy level to manage aphids and if required, spraying of imidacloprid 17.8 SL @ 0.4 ml per litre of water can be given.

3.    Black thrips may cause damage in grapes in flowering stage and berry setting stage. Installing yellow sticky traps is most effective for the control of black thrips. After this, spray of emamectin benzoate 5 SG @ 0.22 gram per litre water or cyantraniliprole 10 OD @ 0.7 ml per litre or spinosad 45 SC @ 0.25 ml per litre of water can be given.

4.    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. Soil drenching with clothianidin 50 WDG (PHI 60 days) may also be given for mealybug management. Entomogenous fungus such as Metarhizium, Beauveria and Lecanicillium can be used for plant wash to reduce mealybug populations. 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.

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

6.    Emamectin benzoate 5 SG @ 88 gram per acre or cyantraniliprole 10 OD @ 0.7 ml per litre water is effective against Spodoptera caterpillars and thrips.

7.    Bunch webbing caterpillars may start damaging bunches in most of the grape areas where humidity is high. The most effective way to control them is to collect and kill them by hand as insecticides may not reach inside the bunch. The caterpillars on leaves are also needs to be killed as they can go inside the bunch later on. Spraying of emamectin benzoate 5 SG @ 0.22 gram per litre water or cyantraniliprole 10 OD @ 0.7 ml per litre is effective to manage them.

8.    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.