Weekly advisory 16 February, 2023 - 22 February, 2023

WEATHER DATA FOR THE PREVAILING WEEK

Date of Fruit Pruning: 15/09/2022

 Thursday (16/02/2023) – Wednesday (22/02/2023)

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

Pan evaporation: 5-6 mm

Amount of irrigation advised :

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 veraison stage till harvesting, apply irrigation through drip @ 8500 - 10200 L/ acre/ day.

4. Whereever temperature is crossing 35°C, donot withhold irrigation during ripening to harvest stage for faster sugar accumulation, as this will lead to loose bunch, thereb affecting the quality of produce.This is especially true in case of light soils and saline soils.

IV. Soil and Nutrient management

Berry Development stage:

1. 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.

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

3. 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.Total potassium application (SOP) should be approx. 60 kg/acre during this stage.Follow this up with Magnesium sulphate @ 10 kg/acre in two splits.

2. Spray Magnesium sulphateand potassium sulphate @ 4g/L in calcareous soil.

3. 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.

4. Manage canopy for adequate sunlight and air movement within the canopy for avoiding/ minimizing problems of berry cracking.

III. Requirement of growth regulators

NIL

IV. Canopy Management

1. The temperature in the vineyard is increasing with the reduction in relative humidity. The night temperature is also increasing. This will affect the water requirement.

2. The increase in temperature also lead to water loss from the leaf thereby increasing the water demand. 

3. Sometimes, the balance of availability of water and demand gets disturbed. Under such conditions, cluster necrosis is experienced in the vineyard. 

4. The availability of nutrient will help till veraison is possible after which the berries do not absorb the nutrients. This is because the cells either do not increases or increases its size indicating its inability to function further. 

5. Many of the times, the grape growers use flood irrigation during the berry veraison stage. This condition also leads to sudden changes in berry pressure for water. This leads to berry cracking. 

6. The use of PGR sprays for berry development is generally done during berry setting stage. Excess use may lead to berry skin thickening. It also lead to delay in sugar development.

7. Considering the above conditions, irrigation to the vineyard is given based upon the berry development stage. Pan evaporimeter can be used to understand the water requirement of vineyard. 

8. Irrigation during early morning or in the late evening will help to reduce the requirement. 

9. Application of nutrients like calcium and magnesium can be considered from berry setting to 10 days before veraison. During this period, the absorption capacity of berry cells is more. 

10. The source:sink relation need to be maintained from berry setting to veraison. Root activity to be checked for better utilization of sources. 

11. At this stage if the knots are formed due to excess PGR, there may be knots on the bunch peduncle or rachis. To control further knot development, apply urea so that the vigor will help to reduce the knot.

12. Flood irrigation can be followed considering the soil type, berry development stage and the period of harvest. 

13. Bunch load management will help to reduce the cluster necrosis problems. Bunch thinning can be performed even upto 65 days after fruit pruning.

V. Disease management

Two sprays of Bacillus subtilis @2g/L may be given for powdery mildew prevention. Bacillus subtilis will also help in bioremediation i.e. reduction of pesticide residues to some extent and for this purpose two sprays may be given at 10 days interval one month prior to harvest.

VI.Insect and Mite management

Growth Stage: Veraison to post veraison stage after October pruning

1. Mealybug and mites population may be noticed due to favourable weather conditions.

2. Buprofezin 25 SC @ 1.25 ml per litre water (PHI 65 days) is effective against mealybugs. If PHI with above insecticide 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.

3. 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.

4. All the cracked/damaged berries should be removed from the grape bunches. These berries should be destroyed by burying them minimum two feet deep in the ground away from the vineyards. It will reduce the scavenging fly population in the vineyard. Ripe banana can act as a good attractant for these scavenging flies. Therefore, banana traps can be made and installed at the rate 5 per acre. To make a banana trap, take a container with small holes at sides and put a fully ripe banana inside it cut into pieces. Pour 2-3 drops of spinosad 45 SC on the banana. Cover the mouth of the container with inverted paper-cone keeping a small hole at the bottom for fruit flies to enter. The berry cracking of grapes should be managed by following suitable viticultural practices.

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. 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.

6. 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.

7. Some areas may see aphid infestation on bunches. Imidacloprid 17.8 SL @ 0.4 ml per litre (PHI 60 days) may be sprayed. If the PHI cannot be maintained than do spot wash with silicon based surfactants followed by washing with water.