Shorea robusta Gaertn.f : A review on its importance, entomological problems and management in the Indian sub-continent

Abstract

Shorea robusta is an ecologically and economically important and dominant timber species in tropical forests of Indian sub-continent. Apart from strong, elastic and heavy heartwood timber, the coppice shoots of Sal are used for making household or agricultural implements and is a good source of firewood. Leaves are lopped for fodder and the flavonoids present in the leaves can be used as an active ingredient of several medicines. Additionally, the processed Sal seeds have a leading role in food and cosmetic sectors. The seed oil has become a significant foreign exchange earner for India. In India, Sal is one of the most affected species in terms of insect attack. Subsequently, insect damages, in varying degrees from seeds to finished products are the major reasons for decline in population of Sal forests. A total of 340 insect species belonging to 56 families under eight orders have been recorded that are associated with Sal in the country. About 145 insect species has been reported feeding on the green standing Sal trees which may be grouped as seed insects, nursery pests, defoliators, stem and root borers and sap suckers. Pammene theristis , for instance is responsible for heavy infestation of the seedlings and seeds of Sal. Major pest during nursery practice is Holotrichia consanguinea which lays eggs in the soil and grubs feed on the root system of the 2-3 years old seedlings of Sal. The major defoliators belong to the order Lepidoptera comprising of 93 species. Notably, Hoplocerambyx spinicornis , the most serious pest and a single species of heartwood borer of Sal is capable of attacking and killing healthy trees of any age and size. About 90 species of timber borers causes damage to Sal, of which six species feed on rotten logs or stumps. The current communication aims to provide a detailed account on different insect pests infesting Sal in India.