This lecture covers key aspects of grape cultivation, focusing on major nutrient disorders, corrective measures, growth regulators, physiological disorders, and pest and disease management. It also discusses optimal harvesting, storage, and raisin production practices, essential for maximizing yield and fruit quality in viticulture.
Introduction to Grape Cultivation
- Grapes (Vitis vinifera) are a major fruit crop grown globally for fresh consumption, raisins, and wine.
- Optimal growth requires balanced nutrition, pest and disease management, and proper cultural practices.
- Understanding disorders and their management is crucial for high yield and quality.
Nutrient Disorders in Grapes
- Common deficiencies: Nitrogen, Potassium, Magnesium, Zinc, Boron, Iron.
- Symptoms include chlorosis, poor fruit set, stunted growth, and leaf necrosis.
- Soil and leaf analysis help diagnose nutrient disorders.
Corrective Measures for Nutrient Disorders
- Apply recommended fertilizers based on soil and tissue analysis.
- Use foliar sprays for micronutrient deficiencies (e.g., ZnSO4 for zinc, Fe-EDTA for iron).
- Incorporate organic manures and green manures to improve soil health.
- Maintain proper irrigation to aid nutrient uptake.
Growth Regulators in Grapes
- Gibberellic acid (GA3) used to increase berry size and improve cluster looseness.
- Apply 25 ppm GA3 at calyptra fall and pepper stages for seedless varieties.
- Potassium chloride (0.2%) sprayed at 20 and 40 days after berry set for uniform ripening.
Physiological Disorders in Grapes
- Berry cracking: Caused by irregular watering or boron deficiency.
- Uneven ripening: Linked to potassium deficiency or hormonal imbalance.
- Poor fruit set: Often due to zinc or boron deficiency.
Major Pests of Grapes and Management
Nematodes
- Apply carbofuran 60 g/vine one week before pruning; irrigate well.
- Use neem cake 200 g/vine and Pseudomonas fluorescens for biocontrol.
Flea Beetles
- Spray phosalone 2 ml/l after pruning; repeat 2–3 times as needed.
Thrips
- Spray dimethoate 2 ml/l for control.
Mealy Bug
- Spray monocrotophos 2 ml/l; use sticky bands and natural predators for IPM.
Major Diseases of Grapes and Management
Powdery Mildew
- Caused by Uncinula necator.
- Symptoms: White powdery growth on leaves, shoots, and berries.
- Management: Sulphur dusting @ 6–12 kg/ha; use resistant varieties.
Downy Mildew
- Caused by Plasmopara viticola.
- Symptoms: Yellowish oil spots on leaves, white downy growth on lower surface.
- Management: Spray 1% Bordeaux mixture; ensure good air circulation.
Harvesting, Yield, and Storage of Grapes
- Harvest only after full ripening for best quality.
- Heat requirement: 2900–3600 degree days for most varieties.
- Average yields: Seedless – 15 t/ha/yr; Muscat – 30 t/ha/yr; Pachadraksha – 40 t/ha/yr; Anab-e-Shahi/Arka hybrids – 20 t/ha/yr.
- Room temperature storage: Up to 7 days; cold storage (-2 to -1.5°C): 40–45 days.
Raisin Production from Grapes
- Raisins are a major by-product in grape-growing regions.
- Grapes with 17° Brix and above are suitable; 20–23° Brix is standard for high-quality raisins.
- Proper drying and storage are essential to prevent spoilage.
Objective Questions
Q1. Which chemical is recommended for nematode control in grapes?
A. Dimethoate
B. Carbofuran
C. Phosalone
D. Monocrotophus
Answer: B
Q2. What is the application rate of neem cake per vine for nematode control?
A. 100 g
B. 200 g
C. 300 g
D. 400 g
Answer: B
Q3. Which pest is managed by spraying Phosalone after pruning?
A. Thrips
B. Mealy bug
C. Flea beetles
D. Nematode
Answer: C
Q4. What is the recommended concentration of Dimethoate for thrips control?
A. 1 ml/lit
B. 2 ml/lit
C. 3 ml/lit
D. 4 ml/lit
Answer: B
Q5. Which disease is controlled by sulphur dusting at 6-12 kg/ha?
A. Downy mildew
B. Powdery mildew
C. Anthracnose
D. Botrytis
Answer: B
Q6. For uniform ripening, grape bunches are sprayed with what concentration of K chloride?
A. 0.1%
B. 0.2%
C. 0.5%
D. 1%
Answer: B
Q7. At which stage are seedless grape clusters dipped in 25 ppm GA for berry size increase?
A. Flowering stage
B. Calyptra fall stage
C. Veraison stage
D. Harvest stage
Answer: B
Q8. What is the annual yield of Muscat grape variety per hectare?
A. 15 t
B. 20 t
C. 30 t
D. 40 t
Answer: C
Q9. What is the optimum storage temperature for grapes in cold storage?
A. 0°C
B. -1°C
C. -2 to -1.5°C
D. -5°C
Answer: C
Q10. Grapes used for raisin making should have a minimum brix value of:
A. 10°
B. 15°
C. 17°
D. 20°
Answer: C