Sugarcane genotypes vis-a-vis top borer (Scirpophaga excerptalis, walker) under field conditions

The experiments to test the reaction of some genotypes towards top borer incidence were carried out at Regional Research Station, Karnal. Out of 131 genotypes which comprised of 39, 46 and 46 genotypes were screened during 1995–96, 1996–97 and 1997–98 crop season, respectively. The average incidence of top borer ranged from 4.0 to 36. 0,2.4 to 56.6 and 0.0 to 10.2 per cent caused by 3^rd and 4^th broods during three years studies. The highly palatable and most preferred genotypes by top borer were 5-91-499, Co 37031 and 5-91-281 in which the maximum incidence was recorded 36.0,56.6 and 10.2 per cent and rated as highly susceptible, highly susceptible and moderately tolerant during 1995–96, 1996–97 and 1997–98, respectively. Only 23 genotypes were recorded as tolerant, 59 as moderately tolerant, 29 as susceptible and 20 as highly susceptible, which consist of 17.56, 45.04, 22.13 and 15.26 per cent of the total genotypes, respectively.