Disease:Anthracnose

Colletotrichum lagenarium

This disease is very serious in the case of watermelon .It rarely affects pumpkin.

Click on the image to enlarge

  • Disease 7
  • Disease 8
  • Disease 9

Symptoms

  • All aerial parts of the cucurbit plants are affected.
  • On the foliage, symptoms appear as yellowish water soaked region that later turn brown or black and dries appear as yellowish water soaked region that later turn brown or black and dries up.
  • Growing leaves may be distorted and coalescing spots may cause death of the entire leaves.
  • When fruit pedicels are infected, the young fruits may darken, shrivel and die.Rounded, dark sunken spots develop on the affected tissues
  • When moisture is present, the fungus starts sporulating along the lesions to produce masses of salmon pink coloured spores.
  • When moisture is present, the fungus starts sporulating along the lesions to produce masses of salmon pink coloured spores.

Epidemiology

The fungus is soil and seed borne, and conidia are spread by rainwater, insects and by agricultural implements. Hot, humid weather is required for the growth and survival of the organism in the host tissue. Disease development occurs at temperatures between 22 and 300C.

Procedure for Observation

Randomly mark five one square meter area from the plot. From each square meter select 5 leaves and fruits at random and record the incidence of disease. Calculate the percent infection.

ETL

  • 8 % for leaves and mere presence for fruits.

    • Control Measures

  • The diseased plant refuse and fruit rind should be destroyed to maintain crop hygiene.
  • Follow crop rotation and destruction of wild host plants.
  • Dry seed treatment with Trichoderma viride @ 2 g/100 g seed or carbendazim at 2.5g/Kg seed is useful for the management of seed borne infection.
  • Apply cow dung and neem cake enriched Trichoderma 10 days before sowing and all along the rows.
  • Spray Pseudomonas fluoresence @ 20 g /L when the plant attains 14 days of age and thereafter at fortnightly intervals depending up on the need.
  • Spraying of the crop, starting at the two leaf stage at ten days intervals with 0.2% mancozeb or 0.1% benomyl or carbendazim, is effective in reducing field infection.