LAUSR

BACKGROUND The massive use of synthetic insecticides strongly affects the level of insecticide resistance in populations of Myzus persicae worldwide. The selection of target site insensitivity- mutations is particularly worrying in areas where agro-industrial crops are vulnerable to the attacks of aphids that vector viruses, as in the case of Tunisia. The knowledge of the resistance mechanisms evolved locally in this aphid pest is a prerequisite to improve and keep the sustainability of integrated pest management strategies. RESULTS Target site mutations were surveyed in several populations of M. persicae collected from peach and potato crops between 2011 and 2017 in three Tunisian regions using real-time allele-specific PCR. The L1014F mutation (kdr locus) was found at a moderate frequency mostly in heterozygous state and the homozygous resistant genotype was very uncommon. The M918T mutation (super-kdr locus) was present in a few heterozygous individuals, while the M918L mutation was detected for the first time in Tunisia and extreme North Africa. This latter mutation showed to be widespread and well established in Tunisia mainly as homozygous individuals and were more abundant on peach than on potato crops. The S431F mutation (MACE) was found in a few heterozygous individuals. No individuals carrying R81T mutation linked to neonicotinoid resistance were detected. CONCLUSION This study points out a critical situation for the efficacy of pyrethroid insecticides to control M. persicae populations in Tunisia. It also confirms the rapid spread of M918L mutation that have been detected in many different areas of the Mediterranean basin. This article is protected by copyright. All rights reserved.