| Abstrakt: |
Tasar silk is produced by wild silkworm belonging to genus Antheraea mylitta D. Tasar silkworm rearing is a traditional activity of tribals inhabiting the central - southern plateau region including the dense humid forest area of Andhra Pradesh, Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Orissa and West Bengal extending to the fringes of Uttar Pradesh and Maharashtra. Tasar silkworm is extremely polyphagous and differs in its adaption to different food plants. The genus Terminalia belongs to family Combretaceae and consists of trees, shrubs and woody climbers, some species (Lagerstroemia) belongs to family Lythraceae. Importance of T. arjuna and T. tomentosa has been well recognized in tropical Tasar industry as these are important primary food plants. Keeping in view the importance of the genus, Central Tasar Research and Training Institute, Ranchi (Jharkhand) is maintaining a Gene Bank of Terminalia where 300 accessions of seven species collected from different parts of the country are being maintained. In recent time, the improved production practices along with the climate change (delayed monsoon and prolonged dry spells) have drastically escalated the insect-pests problem on host plants of tasar-silkworm in a subtle and oblivious fashion. A large number of pests are reported to attack the tasar food plants causing loss to the tune of 15-90%. The major pests are gall insect (Trioza fletcheri minor), Vapourer tussock moths, May-June beetle (Anomala blanchardi), ash weevils (Myllocerus viridanus, M. Undecim-pustulatus, M. transmarinus) and Red beetles (Tricliona picea, T. variables), stem borers (Psiloptera fatuosa, Sphenoptera koenbierensi, Aeolesthes holosercea) and Bark eating caterpillars, Indarbella sp. Besides these insect pests like thrips, Rhiphiphorothrips cruentatus Hood (Thysanoptera: Thripidae), spittlebug, Clovia sp. (Hemiptera: Aphrophoridae) and leaf hoppers (LH), Hishimonus indicus (Sohi) and H. viraktamathi Knight (Hemiptera: Cicadellidae) are also observed infested tasar host plants. To assess the susceptibility of tasar food plant gene bank to major insect pests (stem borer, bark eater, gall fly and termites) at Ranchi, an assessment of the tasar food plants in the Gene Bank of CTR&TI, Ranchi was done. From the observations, it was found that highest infestation of gall fly was seen in Terminalia arjuna; stem borer in L. parviflora; bark eater in Terminalia arjuna and termites in L. parviflora accessions and showed that there is variability in infestation of different insect pests of tasar host plants. This variability of infestation of insect pests may be exploited to develop tolerant hybrids (host plants) against major insect pests under the plant breeding programes of the institute. [ABSTRACT FROM AUTHOR] |
