Susceptibility of very high deep water rice varieties to rice stem borers (Scirpophaga incertulas Walker, Chilo suppressalis Walker and Sesamia inferens Walker)

Susceptibility of 12 rice varieties including some improved breeding lines were evaluated against the rice stem borers under very high deep water conditions (above two metres for at least one month during crop season). The observations were recorded on three crop growth stages, viz., vegetative, panicle initiation and maturity, with respect to infested stems, dead-hearts at vegetative and panicle initiation stages as also white earhead at maturity of the crop. The number of larvae/pupae harbouring the stems and the ratio of different species of stem borers, viz., Scirpophaga incertulas Walker, Chilo suppressalis Walker and Sesamia inferens Walker were recorded. Taking these into consideration, the varieties, Desaria 3, TCA 177, TCA 47-2 and TCA 282 were found susceptible, whereas TCA 12, TCA 214, TCA 269 and Jaladhi-1 were the least susceptible to rice stem borers. S. incertulas predominated during the later stages of crop growth, whereas S. inferens remained a predominant species in the early stage.