Tracking malathion resistance in Spanish Ceratitis capitata populations: prevalence of resistance alleles/haplotypes before and after the withdrawal of malathion

Abstract

Field resistance to malathion was reported for Mediterranean fruit fly (medfly), Ceratitis capitata, populations collected in Spain in 2004 and 2005, when medfly control mainly relied on malathion bait sprays. The mutation G328A in the acetylcholinesterase (AChE) gene (Ccace2) was then identified as the main resistance mechanism in a field-derived resistant strain. However, outdoor plant protection products containing malathion were withdrawn from the European Union in 2009 and other insecticides gained importance, such as spinosad and pyrethroids, though other organophosphates were occasionally used for medfly control for a few years.