Symptoms

1
Module II Economically Important Diseases
Virtual Academy for the Semi Arid Tropics
Lesson 3 Early Leaf Spot

• Symptoms
• Sub-circular dark brown spots are produced on the
  upper leaflet surface.
• The spots are of lighter shade of brown on the
  lower side of the leaflets.
• Yellow halo is seen around the brown spots.

Course on Diseases of Groundnut
2

• Symptoms
• Oval to elongate spots are also seen on stems,
  petioles, and pegs.

3

• Symptoms
• Severe disease attack leads to shedding of
  leaflets (Fig.) resulting in premature ageing of
  the crop.

4

• Management
• As the disease is soil-borne, proper crop
  rotation is important.
• Good weed control is helpful as dense weed growth
  encourages disease development.
• Growing moderately resistant cultivars like ICGV
  89104, ICGV 91114 (EM), ICGV 920920, ICGV 92093
  (MM).

5

• Management
• Fungicidal control of leaf spots is effective.
• Foliar spray with Kavach or Bavistin _at_ 2 g/liter
• of water and 500 liters/ha.
• Copper, sulfur, and copper/sulfur dusts give good
  control of leaf spots and also some control of
  rust. But, these may be expensive.

6

• Management
• Bordeaux mixture spray gives good control of leaf
  spots and rust. But, difficult to prepare
  bordeaux mixture than modern fungicides.
• Maneb and Mancozeb sprays are effective in
  controlling leaf spots and give some control of
  rust.
• Benomyl spray results in excellent control of
  leaf spots. But, likely to stimulate production
  of tolerant strains of fungus.

7
Module II Economically Important Diseases
Virtual Academy for the Semi Arid Tropics
The Lesson 3 on Early Leaf Spot on groundnut
concludes. The Lesson 4 is about Late Leaf Spot
on groundnut. The subsequent Lessons cover other
economically important diseases in groundnut
crop. Select Lesson 4 from Module II contents
Course on Diseases of Groundnut