Population dynamics of early shoot borer, Chilo infuscatellus Snellen on sugarcane as influenced by weather conditions

Abstract

A field experiment on population dynamics of early shoot borer, Chilo infuscatellus Snellen on sugarcane was carried out during 2016-17 crop season at the research farm of CCS Haryana Agricultural University, Regional Research Station, Karnal. Studies on population dynamics revealed thathighest incidence (3.81 per cent in CoH 160, 4.60 per cent in CoH 119 and 3.12 per cent in CoS 767) of C. infuscatellus was recorded during 24^th SMW. Correlation of C. infuscatellus population with various environmental factors revealed that there was a significant positive correlation with maximum temperature (Tmax.) and had a non-significant and positive correlation with minimum temperature (Tmin.) and sun shine hours (SSH) (r= 0.513, 0.287 and 0.452) on CoH 160, (r= 0.504, 0.321 and 0.431) on CoH 119 and(r= 0.537, 0.276 and 0.445) on CoS 767, respectively whereas it has non-significant and negative correlation with relative humidity (morning), relative humidity (evening) andrainfall (r= -0.172, -0.206 and -0.147) on CoH 160, (r= -0.147, -0.172 and -0.130) on CoH 119 and(r= -0.187, -0.223 and -0.160) on CoS 767. Multiple regression analysis of C. infuscatellus population with weather parameters showed that there was 77 per cent (CoH 160), 75 per cent (CoH 119) and 76 per cent (CoS767) variability in dead heart formation due to various environmental factors. The population dynamics revealed by this study have far reaching significance in pest management strategy as integrated control measures may be focused only during the period wherein population exceeds economic threshold level (ETL).