SCIENTIFIC CORRESPONDENCE CURRENT SCIENCE, VOL. 85, NO. 6, 25 SEPTEMBER 2003 725 A. granulata and P. simplex) re- established themselves with several mi- nor species such as non-nitrogen fixing cyanobacteria, Merismopedia punctata. Although M. aeruginosa appeared throughout the following years, it did not form a bloom as in the previous year. The most likely limnological interpre- tation for the sudden emergence of M. aeruginosa is as follows. The lowering of the water level during the dry spell of 1999 may have resulted in greater access for M. aeruginosa to utilize phosphorous mobilized in the anoxic deeper layer, as shown in Figure 1. It is known that Mi- crocystis shows good buoyancy; it comes to the surface and drifts along the wind direction. The schematic model shown in Figure 1 and the available limnological information clearly demonstrate that the biomass regulation or prevention of emergence of Microcystis biomass in Kandy lake is a combination of both top-down and bottom-up approaches 11 . Multiple techniques may also be rele- vant in the case of restoration, since the urban lakes are different from other man-made water bodies 1 . Nevertheless, sound knowledge of hydrology, lim- nological processes and dynamics of the water body and the human activi- ties taking place in the watershed plays a key role in restoration and man- agement. 1. Annadotter, H., Cronberg, G., Aagren, R., Lundstedt, B., Nilsson, P. and Ströbeck, S., Hydrobiologia, 1999, 395/ 396, 77–85. 2. Lammens, E. H. R. R., Hydrobiologia , 1999, 395/396, 191. 3. Pilaou, E. C., Fresh Water , The Univer- sity of Chicago Press, 1998, p. 175. 4. Lewis, W. M., Water Resour. Res. , 1981, 17, 169–181. 5. Silva, E. I. L. and Schiemer, F., ACIAR Proc., 2001, 98, 215. 6. Schiemer, F., Amarasinghe, U. S., Frou- zova, J., Sricharoendham, B. and Silva, E. I. L., ACIAR Proc ., 2001, 98, 111. 7. Talling, J .C. and Lemolle, J., Ecological Dynamics of Tropical Inland Waters, Cambridge University Press, Cambridge, 1998, p. 441. 8. De Silva, P. K. and De Silva, K. H. G. M., Archaeol. Hydrobiol ., 1984, 102, 53. 9. Dissanayake, C. B., Semaratne, A., Weerasooriya, S. V. R. and De Silva, S. H. G., Environ. Int ., 1982, 17, 343. 10. Dissanayake, C. B., Rohana Bandara, A. M. and Weerasooriya, S. V. R., Envi- ron. Geol. Water Sci. , 1986, 10, 81. 11. McQueen, D. J., Johannes, M. R. S., Post, J. R., Stewart, T. J. and Lean, D. R. S., Ecol. Monogr., 1989, 59, 289. Received 5 January 2003; revised accepted 25 June 2003 E. I. L. SILVA Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka e-mail: sil@ifs.ac.lk Cadra cautella Walker (Lepidoptera: Crambidae: Phycitinae) – a pest on Parkia timoriana (DC.) Merr. in Manipur Among the numerous less familiar food used by the local communities in north- east India is a tree legume, commonly known as tree beans (Parkia timoriana) or yongchak by the locals in Manipur. The tree bean, P. timoriana (DC.) Merr. syn. P. roxburghii G. Don belongs to the family Leguminosae and sub-family Mimosoideae 1 . It is one of the most common multipurpose trees in Manipur having high commercial value, and is commonly grown in the backyard of houses, jhums and forests throughout Northeast India 2 . It flowers during the months of September–October and the onset of fruiting starts from November onwards. The pod is available from November till April, and is consumed in all its developmental stages starting from the green, tender pods to the matured, black seeds, fresh or cleaned and sun- dried for future use during the off- season. The associating pungent smell in the seeds is due to the presence of thia- zolidine-4-carboxylic acid (TCA, thio- proline), a cyclic sulphur-containing amino acid 3 . Thioproline is known to be Figure 1. Schematic diagram of limnological processes taking place in Kandy lake during high and low water levels.