Temperature-dependent development of Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) and their validation in semi-field condition

Abstract

The developmental time and survival of the immature stages of Cnaphalocrocis medinalis Guenée were studied at nine constant temperatures (15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and 35°C), 40±10% relative humidity, and a 16:8h light:dark cycle. The total developmental time decreased with increasing temperature between 15 (115.6days) and 32.5°C (20.9days), but increased above 32.5°C. The relationship between the developmental rate and temperature was fitted by a linear model and three nonlinear developmental rate models (Logan 6, Briere 1, and Shi et al.). The nonlinear shape of temperature-dependent development was best described by the Briere 1 model (r2=0.99), and this was supported by statistical information criteria. The total mortality of immature C. medinalis was lowest at 25°C (67.2%) and highest at 35°C (98.1%). The distribution of the developmental times of each stage was described by the two-parameter Weibull distribution equation (r2=0.84–0.96). The predicted date for the cumulative 50% moth emergence was within a variation of one day using the Briere 1 model. The temperature-dependent developmental models for C. medinalis could be applied to determine an optimal management strategy for C. medinalis in paddy fields, and will be helpful in developing a full-cycle phenology model for C. medinalis.