Phosphine resistance to some coleopteran pests in stored grains across Turkey

Abstract: Coleoptera order has important pests as Sitophilus oryzae, S. granarius (Curculionidae) and Oryzaephilus surinamensis (Silvanidae) on stored grains in Turkey. The most effective control method is fumigation with phosphine against the pests. However, many pests developed resistance to phosphine in the world. In this study, 28 strains of S. oryzae, 26 strains of S. granarius and 16 strains of O. surinamensis were supplied from 14 provinces of different regions across Turkey. All strains were tested with bioassays by using two-three weeks old F1 adults to determine the phosphine resistance of adults to discriminating phosphine concentrations of 0.04 mg/l for S. oryzae and O. surinamensis and 0.07 mg/l for S. granarius during 20 hours. Later, the bioassays showed that resistance occured between 3.11 and 200.54 fold in 11 strains (39.3%) of S. oryzae; 3.48 and 5.26 fold in five strains (19.2%) of S. granarius and 388.98 and 459.57 fold in three strains (18.7%) of O. surinamensis. It can be said that phosphine resistance is common and serious in Turkish strains of the coleopteran pests except S. granarius in stored grains.