Insect Pests of Fruit, Plantation, Medicinal & Aromatic Crops (2+1)

1. Fruit fly - Dacus diversus Coq and D.cucurbitae (Tephritidae: Diptera)

Damage

• The maggot tunnel into the fruits and cause rotting and pre-mature fall of the developing fruits. The fly seems to prefer green and tender fruits of pumpkin as it is not able to pierce the hard rind of some other fruits.
  
• The infested fruits can easily be recognized by the distortion or rotting area around the site of oviposition.
  
• Sometimes the young maggot can also be seen eating on the flowers and rarely they may feed on the curcurbit veins with consequent formation of galls.
• It attacks all fruits of cucurbitaceous besides attacking tomato, chillies, brinjal, papaya, guava, peach, dates, citrus etc.
Bionomics

• The adult of B.cucurbitae a reddish brown fly with lemon yellow curved vertical markings on the thorax and fuscous shading on outer margins of wings B. ciliates smaller than B.cucurbitae.
• It thrusts 5 to 15 cylindrical white eggs singly or in groups into flowers or tender fruits.
  
• The fly makes a number of punctures with her ovipositor before the eggs are laid. A resinous secretion ooze out from the injured fruit to repair the punctures.
  
• The eggs hatch out in 1 to 9 days liberating small, dirty white apodous maggots and become full grown in 3-21 days.
  
• Pupation takes place in soil.
  
• Some time it may pupate in the fruit itself.
  
• Pupal period is 3-9 days in summer and 30 days in winter.
  
• The adults are free living on flower vector and can very often be seen congregating on the undersurface of the leaves during morning hours.
Management

• Remove and dispose ripe fruits from trees and ground to suppress fruit fly population.
• Use methyl eugenol traps to attract and kill adult flies.
• Cover fruits with a semi-permeable shrink-wrap film.
• Spray fenthion 1 ml/1 or malathion 2 ml/1 on semi-ripe fruits.