Beet Armyworm, Spodoptera exigua
(Lepidoptera: Noctuidae)

The beet armyworm is found throughout the southern half of the United States. Overwintering is limited to areas that are relatively warm annually. All stages of the beet armyworm can be found throughout the year in areas such as Florida that are relatively warm in climate. The life cycle can be completed in 24 days and many generations may occur per year. Eggs are deposited on the lower surface of leaves near blossoms and the tips of branches. Eggs are circular in shape and greenish to white. Eggs are covered with a layer of white scales that gives the egg mass a fuzzy appearance. The larvae are pale green to yellow and have pale stripes or dark stripes down the back depending on the age of the larvae. Pupation occurs in the soil and the pupa is light brown. The adults are moderate in size and the forewings are mottled gray and brown with irregular banding pattern and a light colored bean-shaped spot. The hind wings are a uniform gray or white color with a dark line at the margin.

The beet armyworm has a wide host range in vegetable crops that includes asparagus, bean, beet, broccoli, cabbage, cauliflower, celery, chickpea, corn, cowpea, eggplant, lettuce, onion, pea, pepper, potato, radish, spinach, tomato, and turnip. The larvae feeding on foliage and fruit cause damage. When sampling for beet armyworm, pheromone traps may be used as well as visual sampling. Crops should be monitored at least twice a week. Insecticides are commonly used to control beet armyworm, but resistance is a major problem in the management of this insect. Beet armyworms can be also be controlled with neem products, insect growth regulators, and Bacillus thuringiensis. Chemical control is more effective when early instars are targeted.

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Beet armyworm, Spodoptera exigua, larva.
(Photographer: L. Buss, University of Florida)

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Beet armyworm, Spodoptera exigua, larva.
(Photographer: J. Castner, University of Florida)

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Beet armyworm, Spodoptera exigua, larva.
(Photographer: L. Buss, University of Florida)

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Beet armyworm, Spodoptera exigua, larva.
(Photographer: J. Castner, University of Florida)

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Beet armyworm, Spodoptera exigua, adult.
(Photographer: J. Capinera, University of Florida)

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Beet armyworm, Spodoptera exigua, adult.
(Photographer: J. Castner, University of Florida)

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Beet armyworm, Spodoptera exigua, larva.
(Photographer: J. Capinera, University of Florida)

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