Monitoring of Target-Site Mutations Conferring Insecticide Resistance in Spodoptera frugiperda
Institute of Crop Science and Resource Conservation, University of Bonn, 53115 Bonn, Germany
Bayer AG, Crop Science Division, R&D Pest Control, 40789 Monheim, Germany
Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, 35020 Padova, Italy
Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
Author to whom correspondence should be addressed.
Received: 22 July 2020
Revised: 12 August 2020
Accepted: 13 August 2020
Published: 18 August 2020
Fall armyworm, Spodoptera frugiperda, is an invasive moth species and one of the most destructive pests of maize. It is native to the Americas but recently invaded (sub)tropical regions in Africa, Asia and Oceania. Fall armyworm larvae feeding on maize plants cause substantial economic damage and are usually controlled by the application of insecticides and genetically modified (GM) maize expressing Bacillus thuringiensis (Bt) proteins, selectively targeting fall armyworm. It has developed resistance to many different classes of insecticides and Bt proteins as well; therefore, it is important to check field populations for the presence of mutations in target proteins conferring resistance. Here, we developed molecular diagnostic tools allowing us to test the frequency of resistance alleles in field-collected populations, either alive or preserved in alcohol. We tested 34 different populations collected on four different continents for the presence of mutations conferring resistance to common classes of insecticides and Bt proteins. We detected resistance mutations which are quite widespread, whereas others are restricted to certain geographies or even completely absent. The established molecular methods show robust results in samples collected across a broad geographical range and can be used to support decisions for sustainable fall armyworm control and applied resistance management.