Population dynamics and occurrence of Spodoptera frugiperda host strains in southern Florida

1. The development of an area-wide management programme for the migratory pest fall armyworm [Spodoptera frugiperda (J. E. Smith)] requires knowledge of its preferred habitats throughout the year and a detailed description of seasonal changes in population numbers. 2. Molecular markers were used to determine the host strain (corn or rice) of male moths captured in sex pheromone-baited traps placed in different habitats in the overwintering areas of southern Florida. 3. The results indicated that rice strain moths were found in all traps and that this strain was the primary population observed in naturalised pasture and wetlands in southern Florida. In comparison, larger populations of both strains and a higher proportion of corn strain moths were observed in areas associated with golf courses, agriculture, or urban development. Corn strain adults were most prevalent during the spring and early summer. 4. These results represent the first geographical survey of fall armyworm host strain distribution in Florida and indicate that corn strain moths are limited in their habitat choice while rice strain moths have a substantially broader range. The localisation of the corn strain population to discrete areas at specific times of the year provides an opportunity to reduce or delay its northward migration.