Weekly advisory 22 June, 2023 - 28 June, 2023

WEATHER DATA FOR THE PREVAILING WEEK

Date of Fruit Pruning: 15/09/2022

 Thursday (22/06/2023) – Wednesday (28/06/2023)

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.

II. Water Management

a. Number of days after foundation pruning: 68

b. Pan evaporation: 6 to 7.5mm

Amount of irrigation advised:

1. Most of 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:

a. Apply irrigation through surface drip @ 3600 to 4200 L/acre per day.

b. 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.

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

 3. Cane maturity stage: Apply irrigation through surface drip @ 3600 to 4200 L/acre per day.

4. 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

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.

6. Check for any interveinal leaf yellowing or marginal leaf yellowing. Interveinal veinal leaf yellowing means lime induced iron deficiency due to calcareous soil. Yellowing of leaf margin coupled with curling means potassium deficiency.

7. To effectively manage calcareous soil, apply 5kg/ acre soluble sulphur through drip every week. Follow it up with foliar spray of ferrous sulphate @2g/L twice at 3 days interval and apply 15-20kg/acre ferrous sulphate thgrough drip. Also spray magnesium sulphate and potassium sulphate @ 3 gm each/ L once only.

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

9. 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.

10. 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.

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

As per the prevailing weather, the temperature is rising while the night temperature is decreasing. The monsoon is still awaited. Under such situations following practices are suggested. 

1) The temperature in major grape growing regions is around 35 degrees while relative humidity is upto 60 percent. Though rains are received, the present condition is favorable for vegetative growth. 

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

3) With the increase in relative humidity, the incidence of thrips will be more. Control of pest immediately after the shoot pinching will help to control incidence. 

4) Though it is not raining, cloudy weather is available. Under the dense canopy conditions, the incidence of powdery mildew is expected. Hence, shoot pinching and training the shoot on wire should be done. 

5) 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. 

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

7) 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. 

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

9) Bark splitting at basal portion of growing shoot 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. 

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

11) 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. 

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

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

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

IV. Disease management

In early pruned areas, application of hexaconazole @0.75ml/L may be given to restrict vegetative growth. In addition it will control powdery mildew infection, if any. Preventive application of Mancozeb and Copper formulations to be continued. Drip application of Trichoderma may be given in areas where there is low to moderate rainfall. In areas where temperature is high, application of Trichoderma may be avoided. In some locations if bacterial spot is visible, application of Mancozeb@ 2g/L may be given. Anthracnose could also be incident and application of carbendazim/ Thiophenate methyl@ 1g/L may be done. Excess application of copper may be avoided.

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.