Disease:Downy Mildew

The disease is common wherever cucurbits are cultivated and occurs in a very serious form when there are intermittent rains during the cropping period.

  • Disease 3
  • Disease 4


  • Usually central leaves are affected first followed by other leaves until the entire plant is wilted.
  • Young leaves are less susceptible. Infection occurs more rapidly on lower surface.
  • The first symptom on the leaves resemble those of mosaic mottling.
  • The fungus cause pale yellowish, angular patches on the leaves often restricted by veins on the upper surface.
  • Gradually the spots turn dark brown and dry up.White downy growth of the fungus is visibleon the lower surface of the affected leaves during humid conditions.
  • During the later stages, the entire leaves are affected and may turn yellow, decay and fall off.
  • On infected plants fruits are few, small with poor taste.


The maximum sporangial dispersal occurs during morning. Cucumber beetles are known to carry sporangia from one plant to another. The disease spreads in fields through dispersal of sporangia by rain drop splashes and beetles. Low nutritional status predisposes the plants to infection.

Procedure for Observation

Randomly mark five one square meter area from the plot. From each square meter select 5 leaves at random and record the incidence of the disease.Count the leaves showing symptoms (even if a spot is present that leaf is considered as infected). Work out the average leaves showing infection.


  • Mere presence
  • Control Measures

  • The crop has to be protected from the pathogen for which weekly sprays of mancozeb 0.3% can be given starting with the appearance of the disease.
  • The interval between the sprayings can be adjusted based on the disease severity.
  • Spray 2% Pseudomonas immediately after observing the incidence.
  • The severely infected leaves/vines should be removed and destroyed before application of the fungicide/bio control agents.
  • Ensure control of pumpkin beetles which helps in spreading of the pathogen.