WEATHER BASED GRAPE ADVISORY

WEATHER DATA FOR THE PREVAILING WEEK

Date of Foundation Pruning: 16/04/2022

Thursday (18/08//22)–Wednesday (24/08/2022)

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 (Dr. A.K. Upadhyay & Yukti Verma)

A)    Days after pruning :125 days

B)    Pan evaporation: 0 to 4 mm

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.      If the soils especially medium and heavy, are saturated with water, then, do not irrigate for atleast 5-7 days till the soil comes to wapsa condition.  The top soil is likely to show dryness but, at lower depth water will be available for the vines. Allow the new growth to stop first before starting irrigation.

3.      Cane maturity stage: Apply irrigation through surface drip @ 1500 -2000 L/acre per day, if only required.

4.      Rmove 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.         In many of the grape growing areas in Nasik, Sangli and other areas, continuous spells of rains have been received and further also possibility of rains are there. The soils are already saturated.  This has affected the rooting activity. Due to prolonged saturation, the roots may have started decaying.  Donot disturb the soil in the root zone. Wait for the soil to come to the wapsa condition before any soil related intervention has to be done.  Growth will be slow, donot worry.  Only after wapsa, fertilizer application should be done.

2.         Due to continuous sprays the leaf will not look healthy, need based sprays should be followed as the leaf health is bound to affect the photosynthate formation.  This will impact cane maturity.

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

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.  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.

5.         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.

6.         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.

7.         Potassium application is required from Cane maturity stage onwards.  Approx. 32 kg of sulphate of potash (soluble grade) should be applied between 90-110 days. Application should be based upon soil test value.  Split the application into atleast five doses to reduce the leaching losses of the potassium.    In calcareous soils, provide foliar application of Sulphate of Potash (@ 4g/L) once in this growth stage.

8.         Apply magnesium sulphate @ 15 kg/acre in two splits.  The application should be done during 60-75 days after pruning. 

Pre-pruning operations – Fruit pruning season

1.      In case pruning is planned during September-October, 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.

5.      In areas where rains have not been received and the irrigation water availability is less, it is suggested to flood the rootzone(only) with water to leach out the salts and wet the entire soil depth before pruning and then cover with mulch.  Thereafter irrigate as per availability of water.

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

-          NIL

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

Based on the growth stages in grape vineyard and change in weather condition during this period, following suggestions are offered.

1.      Though the rains stopped, excess moisture in the root zone is still available. Hence, the roots still might not have been activated.

2.      The shoot growth will be more even the rains stopped.

3.      The growers may experience growth of side shoots. This will certainly form the dense canopy.

4.      In the late pruned vineyard, sunlight requirement by the individual bud on a growing shoot for fruit bud differentiation will not be fulfilled.

5.      Even the vigorous growth (increased in intermodal distance) will lead to formation of horizontal canopy.

6.      Leaf area will also be more thereby leading to excess and dense canopy on a vine.

7.      The roots between two roots will be more activated. This will results into uptake of unutilized nutrients leading to excess growth.

8.      The leaf requirement on a growing shoot is 16 to 17 no. (leaf area of each leaf is around 160-170²ft).  The leaf above this requirement is excess.

9.      The excess growth in terms of increased leaf number may results into delay in cane maturity.

10.  During the rainfall, the new shoots will be more prone to anthracnose nose infection. Once the shoot is infected, the organism will enter into the shoot and after forward pruning, the bunch may get affected.

11.  During this time, the cloudy weather may become favorable for improvement in microclimate thereby increasing the chances of powdery mildew infection.

12.  Open canopy can be the best option to avoid the disease incidence and advance the cane maturity.

13.  To overcome these problems, remove the excess growth, side shoots at the earliest possible.

14.  The late coming shoots on the cordon can also be removed by retaining one bud. Shoot pinching can be done by removing just a growing tip.

15.  Train the shoots on the foliage wires. This will help for aeration in the canopy thereby reducing the humidity.

16.   Spray Boudreaux mixture @ 0.5% in the vineyard just completed the phase of fruit bud differentiation. The concentration can be increased depending upon the advancement of cane maturity. However, Boudreaux sprays are to be avoided in case of colored varieties.

17.   Irrigate the vineyard when fertilizer is being applied through drips. Since the moisture in the root zone is sufficient, irrigation is not advised.

18.  For disease control, biological control can be given the priority.

V. Disease management (Dr. Sujoy Saha)

In many locations, downy mildew is observed and Bordeaux mixture (0.5-1%)/Mancozeb/Metiram/Ziram @ 2-2.5g/l may be applied. Use of systemic fungicides may be avoided as much as possible but if infection is high a single spray of Benalaxyl + mancozeb @2.75g/L may be given. Due to continuous rains in most of the areas anthracnose, bacterial spot and downy mildew may be incident in a moderate scale. Thiophenate methyl/carbendazim@1g/L should be given for anthracnose control. An application of Kasugamycin+Copper oxychloride may be given @ 0.75g/l for the management of both bacterial spot and anthracnose, but specifically it should be more effective against bacterial spot. Two sprays of Kasugamycin+Copper oxychloride at 5-7 days interval will give a good result against bacterial spot. Streptocycline should NOT be applied for the control of bacterial diseases.  Powdery mildew may be disseminated by the rain splashes and initial symptoms may be observed as soon as the rain stops. Application of triazoles like hexaconazole or difenoconazole will control powdery mildew and additional protection against anthracnose will be obtained as well. Foliar application of Bacillus/Trichoderma @ 2-3g/ml should be given during this time to get a control against anthracnose. If rust is observed on leaves, foliar application of chlorothalonil @2g/L may be given.

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

1.    Due to optimum weather conditions, mealybug infestation may be noticed. Use of broad-spectrum insecticides should be avoided for mealybug control. Preventive plant wash, on stem and cordons, of biocontrol agents such as Verticillium, Metarhizium, Beauveria may be given. In case of shoot malformation, remove excess shoot growth and give foliar spray of imidacloprid 17.8 SL @ 0.4 ml per litre water.

2.    In case of thrips or caterpillar infestation, remove excess canopy. Application of fipronil 80 WG @ 0.0625 g per litre or emamectin benzoate 5 SG @ 0.22 g per litre water is effective. Light traps may be installed outside the vineyards to manage moths for reducing caterpillar infestation.

3.    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 or abamectin 1.9 EC @ 0.75 ml/l water is effective.

4.    Red colour stem borer (Dervishiya cadambae) has started egg laying and infestation under bark in grape areas. Install light traps near the vineyards to manage moths of this stem borer. Remove loose bark from stem and cordons and give preventive wash on stem and cordons with biocontrol agent Metarhizium @ 3-5 ml per litre water minimum once in the month during July to September months. If infestation is observed, remove the loose bark and give spot stem and cordon wash with Metarhizium @ 3-5 ml per litre water  or lambda cyhalothrin 5 CS @ 2.5 ml per litre water and 1.5-2 litres water per plant on the infested plants only.

5.    In new vineyards, flea beetle infestation may be observed. In case of heavy infestation, give soil drenching with imidacloprid 17.8 SL @ 1.5 ml per plant and foliar application with spinetoram 11.7 SC @ 0.3 ml per litre or fipronil 80 WG @ 0.0625 g per litre water.