Fruit Fly

Bactrocera dorsalis

Fruit Fly

Bactrocera dorsalis

Fruit Fly

Bactrocera dorsalis

The tomato fruit fly, Bactrocera dorsalis (also known as the Oriental fruit fly), is a major pest of fruits and vegetables in tropical and subtropical regions. It attacks a wide range of host crops, including tomatoes, causing significant yield and quality losses. This pest thrives under warm and humid conditions and has a complex life cycle consisting of egg, larval, pupal, and adult stages. Understanding the pest’s biology and environmental preferences is crucial for developing effective monitoring and management strategies.

Eggs

• Eggs are approximately 0.8 mm long and 0.2 mm wide.

• They are white to yellow-white with a slightly protruding micropyle at the anterior end.

• The chorion has a reticulate pattern, which can only be observed under a scanning electron microscope.

• Eggs are laid below the fruit skin and hatch within 1 to 5 days, depending on temperature.

Larvae (Third Instar Description)

• Size: 7.5 to 10.0 mm long, 1.5 to 2.0 mm wide.

Pupa

• Barrel-shaped.

• Color: White to yellow-brown.

• Retains visible anterior and posterior spiracles.

• Measures about 60–80% of the larva’s length.

• Pupariation occurs in the soil beneath host plants and can last 12 to 26 days, depending on environmental conditions.

Adults

• Adults are part of the Bactrocera dorsalis species complex.

• Wing features:

  • Clear wings with a narrow costal band, not reaching vein R4+5.

  • Cells bc and c are colorless, with minimal microtrichia.

• Color variations:

  • Indian and African populations show paler markings.

  • Southeast Asian populations typically have a darker scutum.

• Adults begin mating about 11 days after emergence and may live over 3 months in lab conditions.

Environmental Preferences

• Temperature:

  • Development occurs between 15°C to 33°C.

  • Optimal development and reproduction occur between 20°C to 30°C.

• Humidity:

  • Relative humidity of 60% ± 10% is ideal for larval and pupal stages.

• Development thresholds:

  • Development slows significantly at temperatures below threshold values.

  • Delayed egg hatching and pupation under cooler conditions.

• Lifecycle duration:

  • Larval feeding lasts 6–17 days depending on temperature.

  • Pupation in soil takes 12 days at 24°C, but up to 26 days in cooler weather.

• Activity period:

  • Adults are active year-round, particularly in warm, moist environments with abundant host fruits.