WEATHER BASED GRAPE ADVISORY

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

  II. Water Management

a. Number of days after foundation pruning: 75

b. Pan evaporation: 2 to 4 mm

Amount of irrigation advised:

Amount of irrigation advised:

1.      All the grape growing regions are forecasted to receive from drizzling to light rains.  The irrigation water application should be based upon the growth of the vines.  In case rain exceeds 5 mm on a given day, irrigation water application can be skipped for that day.  Generally, under wapsa (field capacity) condition of the soil, donot give irrigation.

2.      Fruit Bud Differentiation stage: Apply irrigation through surface drip @ 1500 to 2000 L/acre per day.

3.      Cane maturity stage: Apply irrigation through surface drip @ 1500 – 2000 L/acre per day.

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

5.      In case of monsoon rains, remove mulch cover on the bund and allow the rain water to seep into the soil. This will leach the accumulated salts in the rootzone.  The mulch so removed can be mixed with the soil to improve the soil porosity.

Nutrient management

1.        After current rains, give foliar spray of SOP @ 3-5 g/L depending upon canopy size.

2.        In case of calcareous soils where acute iron deficiency is observed, repeatedly spray 2-3g/L Ferrous sulphate two to three times at 3 days interval followed by 15-20 kg/ acre  Ferrous sulphate application through drip.  The fertigation dose should be split into atleast 3 doses of 5kg each.  Apply 5kg/ acre soluble sulphur through drip every week.  Also spray magnesium sulphate and potassium sulphate @ 3 gm each/ L once only.Keep a close watch on the development of leaf blackening symptoms if irrigation water contains sodium more than 100ppm.

3.        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.

4.        In coloured varieties like Jumbo, Nanasaheb Purple etc., leaf curling along with reddening/ bronzing of the leaf margin can be observed if potassium deficiency is there.  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.      After current rains, give foliar spray of SOP @ 3-4 g/L depending upon canopy.

2.        Based upon soil test values, apply 20 – 25 kg phosphoric acid or 150 kg 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.

3.        Donot apply any water soluble fertilizer having nitrogen.

4.        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.

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

Cane maturity stage

1.        Potassium application is required from Cane maturity stage onwards.  Approx. 64 kg of sulphate of potash (soluble grade) should be applied in this stage.  Split the application into atleast five doses to reduce the leaching losses of the potassium.  Apply 15 kg SOP in two – three splits during this week.  In calcareous soils, provide foliar application of Sulphate of Potash (@ 4g/L) once in this growth stage.

2.        Apply magnesium sulphate @ 15 kg/acre in two splits.  The application should be done during 60-75 days after pruning.  In calcareous soils, provide foliar application of Magnesium sulphate (@3g/L)   in this growth stage.

3.        In case due to rains and for preventive control, if bordeax or copper sprays are given, then there is possibility of leaf reddening in coloured varieties like Krishna Seedless etc. No specific pattern will be there.  This may be due to copper toxicity.  Regulate copper sprays.

Pre-pruning operations – Fruit pruning season

1.      In case pruning is planned during August - September, raise Sunnhemp or Dhaincha for green manuring purpose.

2.      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.  The application should be alongwith FYM/compost etc.  They should be mixed in the soil and not left on the top.

3.      In case of calcareous soils, if SSP is applied as basal dose, mix with FYM/compost etc. to avoid phosphorus fixation.

4.      Test the soil and irrigation water, to plan for nutrient and water management during fruit pruning season.

III. Canopy Management

 The practices followed during this week are as below.

1. The rains received during the last week will help to increase the relative humidity and thus the vigor of the vine. 

2. Shoot vigor will be more. Hence, shoot pinching should be taken up on priority basis. 

3 Under the dense canopy conditions, the incidence of powdery mildew is expected. Hence, shoot pinching and training the shoot on wire should be done. 

4. Early cane maturity is important. Hence, shoot pinching and shoot training should be given priority.  This will help to receive sunlight and proper aeration in the canopy. Microclimate can get reduced under such situations. 

5. Application of potash and reduction of irrigation water will also help to attain cane maturity in the vineyard. 

6. In the vineyard the growers may experience milky white color of shoots at bottom. This is the indication of cane maturity.  Reduction of irrigation and potassium spray will help to advance the cane maturity. 

7. Spraying of biologicals during humid conditions  can help to control the disease incidence. 

8. Bark splitting at the basal portion of growing shoots is being experienced. This is nothing but the skin rupturing due to increased temperature and relative humidity. Hence, it will not have any adverse effect. 

9. In the vineyard where cordon development is in progress, a second installment can be done. The last shoot can be tied on the cordon. This shoot needs to be pinched at 4 to 5 leaf only. 

10. Application of PGR for fruit bud differentiation is necessary as prevailing weather is not favorable. Hence, 6BA and Uracil applications with recommended doses should be followed. 

11. Once the side shoots start emerging,  spray of P and K grade fertilizer with a minimum dose of 2 to 2.5 g per litre of water can be given. 

12. In rootstock, shoot thinning can be undertaken. Retention of 3 to 4 healthy, straight growing shoots will be useful for grafting. 

13. The shoot thickness of rootstock should be 8 to 10mm at about 1.25 feet above the ground. 

14. The side shoots on rootstock should be removed in the installment so that the required thickness for grafting can be achieved. 

15. Spraying the vineyard with 0.5% bordeaux mixture at the initiation of shoot maturity (milky white color stage of shoot) will help to achieve ealy cane maturity and disease control.

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IV. Disease management

Anthracnose is incident in many locations and application of carbendazim/ Thiophenate methyl@ 1g/L may be done. The spray may be repeated after 7 days. If the problem persists, application of hexaconazole @0.75ml/L may be given to control anthracnose. Additionally, it will control powdery mildew infection, if any. Preventive application of Mancozeb and Copper formulations to be continued. Drip or foliar application of Trichoderma may be given during this week as moist and humid conditions will help in multiplication of the biocontrol agents.   In some locations if bacterial spot is visible, Kasugamycin 5% + Copper Oxychloride 45% WP @ 750g/ha may be applied.  The spray has to be repeated after 5-7 days. Streptocycline should NOT be appied for any bacterial diseases. Excess application of copper may be avoided. Spraying has to be done when there is no rains for at least 1.5-2 hours.

V.    Insect and Mite management

1.    Adults of stem borer Stromatium barbatum and red stem borer, Dervishiya cadambae start emerging during June. Installation of light traps will be helpful in monitoring the initiation of emergence of stem borer adults. Run the light traps for 3 hours daily, during evening between 7.00 pm – 10.00 pm and destroy the collected beetles in water mixed with insecticide. Application of neem oil or neem seed kernel extract or hanging neem leaves inside vineyards may act as repellant for adults of Stromatium barbatum. Loose bark on main stem and cordons act as hiding places for both stem borers, removing loose bark will reduce egg laying in vineyards.

2.    Chafer beetles are adults of white grubs. They start emerging after good rains during May-June months. They are active during nighttime and remain hidden during the day. After mating about 50 eggs are laid by a single female in the soil and where they feed on the roots. However, the damage to roots by their grubs in grapes is not a major problem. The major damage is caused by the adults by feeding on leaves. Mostly grape plants at the border of the vineyard are affected. Foliar application of lambda cyhalothrin 4.9 CS @ 0.5 ml per liter water at night is effective to kill the beetles.

3.    Spraying of imidacloprid 17.8 SL @ 0.4 ml per litre water will help in controlling mealybug on new growth.

4.    In case of thrips or caterpillar infestation, application of fipronil 80 WG @ 0.0625 g per litre or emamectin benzoate 5 SG @ 0.22 g per litre water is effective.

5.    Remove excess growth to manage thrips post second pinching.

6.    Mite infestation may start appearing, therefore, monitor the vineyards carefully. If mite infestation is observed, sulphur 80 WDG @ 1.5-2.0 gram per litre water is effective.

7.    This year many farmers have reported problem of scale insect in their vineyards, especially in Sangali region. To manage scale insect, remove loose bark from infested grapevines and scrap scale insects manually. Afterwards, wash main trunk and cordons of infested plants with imidacloprid 17.8 SL @ 0.4 ml per litre water + Metarhizium anisopliae @ 3 ml per litre water.