Pest:Fruit fly

Bactrocera cucurbitae

Trypetidae

Fruit fly is a major pest of cucurbits, especially bitter gourd and snake gourd. The adult is a reddish brown fly with lemon yellow curved vertical markings on thorax and brown shading on the outer margins of wings. The fly measures about 8 mm across stretched wings. Female lays eggs in cavities in fruits made with the help of ovipositor. Eggs are deposited 2-3 mm deep in fruits singly and sealed with gummy substance produced by the ovipositor. Up to 100 eggs are laid. Eggs hatch in a day and emerging maggots bore in to the fruit and feed on internal contents, and become full grown in about a week's time. The full grown maggot is 9-10 mm in size, leg less and yellowish white. Body is stout at one end and tapers towards the head end. The full grown maggots fall to the ground and pupate in the soil for a week.

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  • pest 01

Symptoms

  • Even the egg laying process causes damage as there is chance of microorganisms gaining entry into the fruit through the injury formed by the ovipositor on the fruits.
  • The emerging larvae tunnel and feed within the fruit which, as a result rot and drop.
  • Rotting is aggravated by microorganism .Fruits of all stages are damaged.
  • In unprotected gardens damage may be upto the tune of 90-100 %.

Procedure for Observation

Mark out 5 one meter square area at random from the plot. Assess the percentage of fruits damaged and work out the average.

ETL

  • 5 % damage

    • Control Measures

  • Regularly collect the infected fruits and destroy by putting it in fire.
  • Cover the fruits as far as possible at the earliest with paper cover or perforated polythene tubes of required size.
  • Apply neem cake at 100 g per pit about 10 days before sowing so as to manage the pupae present in soil.
  • Suspend different types of traps at 2.5 meter spacing.
  • Banana trap- Take 100 ml of water and add 20 g ripened banana pulp. Mix 10 g melted jaggery and poison it with 2 drops of insecticide -malathion. Transfer it to a medium sized (500 ml) bottle provided with 4 holes in the middle, large enough for the fly to enter. Suspend the traps in trellies .
  • Fish meal trap- Place 10 grams of moistened dried fish, preferably powdered ,in a coconut shell ,add 2 drops of malathion and suspend in trellies Trap adult male fruit flies using cue-lure (pheromone) plywood blocks containing 6:4:1 mixture of ethyl alcohol, cue-lure and malathion respectively. Reset traps at 4 months interval. Hang this pheromone traps @ 10 numbers per Ha.
  • Fruit fly traps can also be made by taking 20 g of banana pulp poisoned with 2 drops of malathion in yellow painted coconut shells.
  • Apply Beauveria bassiana and Paecilomyces lilacinus in the basins.
  • In large gardens, apply carbaryl 50 WP 0.2% or quinalphos 0.05 % or malathion 0.15% spray fluid containing 10 g jaggery per liter at fortnightly intervals at flowering and fruit initiation stage . Spray as course droplets, on the lower surface of the leaves.
  • Spray Beauveria bassiana or Verticillium lecanii @ 20 g or 5 ml/Liter.