WEATHER BASED GRAPE ADVISORY

II. Water management

             a. Number of days after foundation pruning: 58

           b. Expected Pan evaporation:2.5 to 6 mm

Amount of irrigation advised:

1.      There is possibility of drizzling to light rains in many regions.  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 fruit bud differentiation stage, shoot vigour to be controlled and hence, the irrigation water applied should be from 2000 to 3500 L/ acre/ day.

4.      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.

5.      Cane maturity stage: Apply irrigation through surface drip @ 2000 to 3500 L/acre per day.

6.      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.

 Soil and Nutrient management:

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.

8.        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.

9.        If weather forecast predicts good rainfall, then give foliar spray of SOP @ 4-5g/L depending upon the canopy size, before the advent of rains.

Cane maturity stage

1.        After current rains, give foliar spray of SOP @ 4-5 g/L depending upon canopy.

2.        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.

3.        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.

4.        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.

5.       To effectively manage calcareous soil, apply 5kg/ acre soluble sulphur through drip every week.  Also spray magnesium sulphate and potassium sulphate @ 3 gm each/ L once only.

6.       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.

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 help for uniform and early bud sprout in late pruned vineyards.

3) Even in the late 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.

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

5) In many of the grape vineyards, delayed or no bud sprouts is experienced. Application of urea @ 1.0 kg/acre for 3 to 4 times (alternate day) and spray @ 0.30 to 0.50 g/L water during evening time will help for bud sprouts. However, Excess dose for spray may cause scorching on emerging leaves.

6) In many of the grape vineyards, hailstorm and heavy rainfall caused the leaf damage as well as injury on the tender shoots. In case of light injury, only spray of copper- based fungicides can be taken.

7) In case of severe damage, the fresh re-cut of damaged shoots can be taken up. Immediately after the re-cut, copper fungicide sprays cane be taken. In addition, application of nitrogenous fertilizer (urea/ammonium sulphate) can be followed for early sprouts.

B) New vineyard:

1) 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.

2) 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.

3) While developing the cordons, the “stop n go” method to be followed. The growth turned on cordon wire for cordon development should be pinched at about 7-8 nodes. The side shoots can then be pinched at 3-4 nodes. This will help for extension of cordon in the same season to fulfil the requirement of canes per vine during the first year only.

4) Spray of 6 BA @ 10 ppm and Uracil @ 25 ppm is required for fruit bud differentiation.

5) The growing shoots damaged by hailstorm or heavy rains need to be protected. The spray of copper fungicides on the wound will protect the vines from fungal infection.

IV. Disease management

In early pruned areas application of Bordeaux mixture may be done. Application of copper hydroxide @1.5-2g/L may also be given. It is not necessary to apply any systemic fungicides at the present conditions. Light rains as incident in many regions will be beneficial and there is no immediate threat of any diseases in a higher scale.In Sangli, a preventive spray of Kasugamycin 5% +Copper Oxychloride 45% WP @750g/ha, may be given in areas which was affected by bacterial spot and anthracnose in the fruiting season.

V. Insect and Mite management

1.    Adults of stem borer Stromatium barbatum start emerging during first fortnight of 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 Stromatium barbatum, 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.