Crop Production
Yellowstriped Armyworms in Hemp
1 min read
Learn to identify and manage yellowstriped armyworms, which can damage hemp and other crops.
Identification
- Appearance is gray or black with two yellow stripes along each side of the body.
- Size is up to 1 3⁄4 inches.
- Young larvae are often found in groups but spread out as they get older.
The Life of a Yellowstriped Armyworm
- Yellowstriped armyworms feed on a variety of crops including hemp, tomatoes, corn, cotton, and other vegetables.
- They overwinter in the soil as pupae and emerge in the spring.
- Adult female moths lay egg clusters on the underside of leaves.
- These clusters can contain hundreds of eggs that hatch in 3 to 5 days.
- Larvae feed for about 3 weeks before moving into the soil to pupate.
- There are between 3 and 5 generations of yellowstriped armyworms each year.
Damage
- Damage is caused by the larval form of the moth.
- Yellowstriped armyworms can be found on hemp throughout the growing season.
- Young larvae will feed on the foliage of vegetative hemp without causing economic damage
- In years with large yellowstriped armyworm populations, they can be found in reproductive hemp later in the season. Caterpillar feeding on floral structures can lead to yield and quality loss.
Management
- Younger armyworms are easier to control.
- Plants should be scouted regularly throughout, beginning with young plants.
- Young seedlings are vulnerable if large numbers of armyworms are feeding.
- Hand removal of caterpillars is an effective means of control.
- Bacillus thuringiensis works well as biobased control of yellowstriped armyworms in hemp, but complete coverage is essential. Multiple applications may be necessary.
- Use the Farming Basics Mobile App to locate Alabama Extension personnel for any questions.
Kaylee Hirsch, Student Research Assistant, and Katelyn Kesheimer, Extension Specialist, Assistant Professor, both in Entomology and Plant Pathology, Auburn University
Reviewed July 2023, Yellowstriped Armyworms in Hemp, ANR-2808