Management of leaf gall midge and stem capsule borer in aonla

Abstract

The aonla (Emblica officinalis Geartn) belonging to family Euphorbiaceae and sub family Phyllanthoidae is an important indigenous fruit tree of india. It has great medicinal and nutritional value. It is also now- a days gaining popularity among farmers and consumers and has immense potential of cultivation in arid and wasteland. In Rajasthan, it is being cultivated in area of 1,565 ha with an annual production of about 11,187 tons (Anon, 2017). The aonla fruits are a rich source of Vitamin C. The special attribute is its capacity to retain Vitamin C even in a dried stage which is not possible in other fruits. One part or other is used in the cure of cough, bronchitis, jaundice, diabetes, dyspepsia, diarrhea and fever. Fruit pulp contains 14 g of carbohydrate, 0.5 g protein, 1.2 g iron, 0.3 mg vitamin B and 600 mg of Vitamin C per 100g. The probable centres of origin are the South and Central India, Sri Lanka, Malaysia and South China. Though aonla is a subtropical fruit, it thrives very well and comes to yield in tropical humid conditions also. Aonla was supposed to be free from major insect and disease menace. With lapse of time and intensification of its cultivation, number of insects and diseases has started feeding and infecting at various stages and causing considerable damage. Lal et al. (1996), Haseeb et al. (1990, 2000), and Jhala et al. (2003) reported occurrence of fruit borer, midge and leaf cutting weevil for the first time in northern and western India. Though, it is considered to be a hardy fruit crop, not less than 30 insect and mite species have been recorded feeding on this scared tree from different places, mostly from India (Lakra, 1996). Aonla is a widely cultivated arid fruit crop and severely affected by stem capsule borer (Betousa stylophora Swinhoe) and leaf gall midge (Asphondylia phyllanthi Felt) causing having losses in fruit yield. The larva of Betousa stylophora feeds inside the gall on the succulent woody tissues and pushes out excreta through a small hole at one end, kept guarded by a mesh work of silken threads. There is only one larva in each gall which remains confined in an ellipsoidal cavity carved out in gall. The mature galls measure 20-26 mm in length and 10-15 mm across. The gall is a hollow swelling/localized tumescence of the tender shoot, irregular, roughly, spindle shaped- resembling 'Snake charmer's flute'. In the beginning of the infestation terminal shoots swell, which increases in size with the passage of time, full size galls can be seen in the month of October-November.