Abstract :
Field experiment was conducted to investigate the nature of damage caused by sugarcane plassey borer C. tumidicostalis. Generally, there are two phases of infestation of the pests known as primary and secondary infestation. From the investigation, it was observed that the mean number of internodes damaged was more or less similar (1 to 3 internodes) in both the primary and secondary infestation. The mean number of damaged internode was 1.88, 2.06 and 2.42 which was slightly more in the secondary infested canes with 1.78, 2.56 and 2.74 in August, September and October, respectively. However, there was a great variation in the length of spindle damaged by the larvae in primary and secondary infested cane. Similarly, the mean length of internode damaged was more in primary infested canes than secondary infested canes. The mean proportion damaged length caused by the larvae in primary infested cane was 0.46, 0.45 and 0.41 during August, September and October as against 0.18, 0.13 and 0.16 in secondary infested cane, respectively.
Keyword :
plassey borer, primary infestation, secondary infestation, spindle