Diseases Management in Grape Nursery

1
Diseases Management in Grape Nursery
Grape seedlings are susceptible to diseases like
Anthracnose, downy mildew, powdery mildew, leaf
spot, leaf blight, rust which require timely care
and management. Anthracnose Small brown or
grayish black lesions develop on tender shoot and
young leaves. Rain and dew favor the spread of
disease. These lesions develop into small holes
on leaves and reduce the effective leaf area.
Fungus causes cankers on the petioles and veins,
and leaves become twisted and deformed.
2
Anthracnose

• Control Measures
• All affected plant parts showing spots, lesions
  and cankers should be removed and burnt or buried
  deep in the soil.
• The disease is more problematic during October
  and November months, when new shoots and branches
  are growing, that should be protected.
• Spraying of grape seedling with fungicides like
  Bordeaux mixture _at_ 0.5 or Copper Oxychloride _at_
  0.15 or Carbendazim _at_ 0.1 are effective
  against this disease.

3
Downy Mildew

• Initial symptom of disease appear as light yellow
  spots on the upper surface of leaves with
  corresponding white spots on the lower side which
  later turn brown.
• The grape seedlings shows reduced and stunted
  vegetative growth development.
• Light and continuous rains, heavy dew with high
  humidity and low temperature favors the
  development of this disease.

Downy Mildew on grape leaves
Downy Mildew on grape leaves
4
Downy Mildew

• Control
• Pruning of the vines after the second week of
  October helps to minimize the damage by downy
  mildew disease. All affected portions of the vine
  should be removed at the time of pruning and burn
  to destroyed immediately.
• Bordeaux mixture (0.5), Copper Oxychloride
  (0.1), Mancozeb (0.1), Metalaxyl (0.1) or
  Fosetyl Al (0.1) fungicides are effective
  against this disease.

Leaves of grapes affected by downy Mildew
5
Powdery Mildew

• It is the second most destructive disease in
  grape after downy mildew.
• The disease develops under warm and dry
  conditions. Shade or diffused sunlight helps in
  the development of this disease.
• The diseases is characterized by the presence of
  white powdery ash like coating in patches on both
  sides of the leaves and growing young shoots.
• The affected leaves turn pale and curl up.
  Affected shoots remain weak and immature. Buds
  affected during growing season fail to sprout
  after pruning.

Leaves Affected by Powdery Mildew
Leaves Affected by Powdery Mildew
6
Powdery Mildew

• Control
• It can be controlled by spraying Wettable Sulphur
  (0.75 gm /10 litres of water) or dusting Sulphur
  powder (20 kg / ha) in the morning. The affected
  plant parts should be thoroughly coated with the
  dust.
• Systemic fungicides like Bayleton (4 gm / 10
  litre of water) or Calaxin (2 ml /10 litres of
  water) or Benomyl (2.5gm /10 litres of water)
  offer better and prolonged control of the
  disease. Spray should be done from November to
  February.

Leaves Affected by Powdery Mildew
7
Bacterial Leaf Spot

• The disease is more prevalent during June to
  August and again in February to March.
  Temperature range of 25-30OC and Humidity of
  80-90 is favorable for the disease development.
• The young growing shoots are affected initially.
  The symptoms appear as minute water soaked spots
  on the lower surface of the leaves along the main
  and lateral veins. Later these spots fuse to form
  larger patches.

Leaves Affected by Leaf Spot
Leaves Affected by Leaf Spot
8
Bacterial Leaf Spot

• Control
• Collecting and burning infected plant parts
  minimizes spread of disease.
• Streptocycline (500 ppm) is very effective as a
  prophylactic spray. Weekly sprays of copper
  fungicide and Bordeaux mixture given from last
  week of October are effective to prevent the
  incidence and spread of the disease.

Leaves drying due to Leaf Spot
Petiole Affected by Leaf Spot
9
Leaf Blight

• Leaf blight disease appears in June to December
  months.
• Small yellowish spots first appear along the leaf
  margins, which gradually enlarge and turn into
  brownish patches with concentric rings. Severe
  infection leads to drying and defoliation of
  leaves.
• Control
• Bordeaux mixture (0.5), Mancozeb
  (0.1),Topsin-M(0.1),Ziram (0.25) or Captan
  (0.1) are to be sprayed alternatively at weekly
  intervals.

Leaf Blight in Grapes
Leaf Blight in Grapes
10
Rust

• The weather conditions during July to December
  favors the development of the rust disease.
• The symptoms are in the form of numerous orange
  colored pustules on the lower surface of the
  leaves.
• In case of severe infection such pustules cover
  the entire leaf surface leading to severe
  defoliation.

Rust in Grapes
Rust in Grapes
11
Rust

• Control
• Rust is controlled by applying 3-4 sprays of
  Baycor (0.1) or Chlorothalonil (0.1) at
  fortnightly intervals during July to August and
  January to February.

Rust in Grapes
12
Care to be Taken while Spraying

• Systemic fungicides are more effective than
  non-systemic fungicides. However, more than 2-3
  sprays of systemic fungicides should be avoided.
• Continuous sprays with systemic fungicide
  develops resistance in pathogens and help in the
  resurgence of diseases like Alternaria ,
  Botrydiplodia etc.
• It is recommended to take a spray of non-systemic
  fungicide in between two successive sprays of
  systemic fungicides.