Beet armyworm
Spodoptera exiguaSpodoptera exigua is a highly dispersive, polyphagous species that is a serious pest of vegetable, field and flower crops. Susceptible crops include asparagus, cabbage, pepper, tomato, lettuce, celery, strawberry, eggplant, sugar beet, alfalfa, and cotton.
S. exigua is native to Southeast Asia but is now found in Africa, Southern Europe, Japan, Australia and North America. It lacks a diapause mechanism and can only overwinter successfully in warm regions or in greenhouses. Nevertheless, because of its dispersal abilities, S. exigua will regularly invade temperate areas and cause damage during the growing season. The larvae are gregarious and may feed in large swarms, causing devastating crop losses. Larvae feed on both foliage and fruit and cause contamination of the crop. As they mature, the larvae become solitary. One generation can be produced in as little as 21-24 days.
Beet armyworm resistance profile
Several biochemical mechanisms may contribute to the evolution of insecticide resistance in S. exigua. These mechanisms can act separately or in concert.
- Enhanced metabolic detoxification, including increased activity of esterases, mixed-function oxidases, and microsomal-O-demethylase.
- Target site insensitivity.
- Sequestration by proteases or esterases, efficient cellular repair or an increase in the immune response.
Known resistance: Carbamates – Group 1A Organophosphates – Group 1B Phenylpyrazoles (Fiproles) Group 2B Pyrethroids – Group 3A Neonicotinoids – Group 4A Spinosyns – Group 5 Avermectins, Milbemycins – Group 6 Pyrrols – Group 13 Benzoylureas – Group 15 Diacylhydrazines – Group 18 Tolfenpyrad – Group 21A Indoxacarb – Group 22A Metaflumizone – Group 22B Unknown or uncertain MoAs – Group UN
