Phosphine resistance in Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) from different geographical populations in China

Abstract

This study was carried out to determine the level of phosphine resistance in 16 Rhyzopertha dominica (Fabricius) populations that were collected from ten provinces and one municipality in China following the Food and Agriculture Organization’s (FAO) standard method. Results showed that the 50% lethal concentration (LC₅₀) of phosphine to these R. dominica populations ranged from 0.017 to 4.272 mg/L. Of the 16 populations, 5 were of low resistance, 6 were moderately resistant, and 5 were high resistant. The instantaneous rate of population increase (r_i) was correlated with phosphine resistance followed by the Exponential model (y = 0.037e-^0.005X, R² = 0.937). The relationship between the types of grain storage and the phosphine resistance of R. dominica population were also discussed.

Key words: Phosphine resistance, instantaneous rate of population increase, Rhyzopertha dominica, China.