Striacosta

Lafontaine, 2004

western bean cutworm (for sole species S. albicosta)

Species Guides

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Striacosta is a of in the Noctuidae, established by Lafontaine in 2004. The sole , Striacosta albicosta (western bean ), is an agricultural pest native to North America. The species underwent significant range expansion from the western Great Plains to eastern North America beginning in 1999. Larvae are serious pests of corn and dry bean crops, with documented resistance to Cry1F Bt protein.

Striacosta albicosta 1 by Jacy Lucier. Used under a CC BY-SA 4.0 license.Striacosta albicosta by Jacy Lucier. Used under a CC BY-SA 4.0 license.Striacosta albicosta 2 by Jacy Lucier. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Striacosta: /ˈstraɪ.əˌkɔstə/

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Identification

The Striacosta is recognized by its single included S. albicosta. are medium-sized noctuid . Larvae can be distinguished from similar corn-feeding caterpillars by their feeding injury pattern: western bean larvae feed on corn ear reproductive parts, typically entering through the silk channel and feeding on kernels, unlike corn earworm (Helicoverpa zea) which often feeds deeper in the ear tip, or fall armyworm (Spodoptera frugiperda) which may cause more ragged feeding damage.

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Habitat

Agricultural croplands, specifically corn (Zea mays) and dry bean (Phaseolus vulgaris) fields. Soil constitutes an important component as prepupal and pupal stages occur in soil.

Distribution

Native to western Great Plains of North America (western Nebraska, Kansas, Idaho, eastern Colorado). Range expanded beginning 1999/early 2000s to U.S. Corn Belt, Texas, New York, Canada, and Mexico. Climate modeling indicates potential suitability for establishment in Europe, Asia, Oceania, South America, and Africa.

Diet

Larvae feed on reproductive parts of corn and dry bean plants. Feeding is concentrated on corn ears and dry bean pods.

Host Associations

  • Zea mays - primary corn ears
  • Phaseolus vulgaris - primary dry bean pods

Life Cycle

Includes , larval, prepupal, and pupal stages. Prepupal and pupal stages occur in soil.

Behavior

Documented range expansion from western to eastern North America since 1999, hypothesized to result from ecological factors (climate, resource availability, absence of natural enemies) and agronomic factors (increased cultivated areas, anthropogenic , management practices). Documented resistance to Cry1F Bt protein has been observed.

Ecological Role

Agricultural pest . Larval feeding causes direct yield losses up to 40% in corn and 10% in dry beans. Feeding damage facilitates secondary fungal in corn ears and exposes dry bean pods to and other pests.

Human Relevance

Significant economic pest of corn and dry bean production. Management includes Bt crops (though resistance to Cry1F exists), applications, and cultural practices. Non-Bt planting is recommended for resistance management. Subject of insecticide resistance management programs and predictive modeling for range expansion under climate change.

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