Chrysodeixis

Adults distinguished from similar Plusiinae by specific wing pattern elements, particularly the configuration of metallic markings on forewings. Larvae distinguished from true loopers (Geometridae, which have only two pairs of prolegs) by presence of three proleg pairs. Within Plusiinae, larvae distinguished from related genera such as Trichoplusia and Rachiplusia by subtle morphological features including spinneret shape and thoracic pigmentation patterns. Chrysodeixis includens specifically identified from C. chalcites by geographic distribution and host associations in North America.

Agricultural and natural habitats supporting host plants. Larvae found on foliage of legumes (soybean, bean), solanaceous crops (tomato, potato), and various other herbaceous plants. Adults nocturnal, attracted to light.

Widespread across North America, Central and South America, Europe, Asia, Africa, and Oceania. Individual species have more restricted ranges: C. includens primarily in the Americas (expanding from North America into South America), C. chalcites in Europe and Asia, C. eriosoma in Australia and New Zealand, C. argentifera in Australia.

Multiple generations per year in temperate and tropical regions. Activity peaks during late growing season (July–September in northern hemisphere) when host plants are at reproductive stages. Overwintering stage varies by species and latitude.

Larvae are folivores, feeding on leaves of diverse host plants. Major crop hosts include soybean, tomato, tobacco, bean, and various other legumes and solanaceous plants. Feeding typically begins on lower leaf surface between veins (window-paning), progressing to full-thickness defoliation and skeletonization as larvae mature.

Holometabolous development with egg, larva (five instars), pupa, and adult stages. Eggs hatch in 3–5 days. Larval development spans 2–3 weeks under favorable conditions. Pupation occurs in soil or leaf litter. Adult emergence after 1–2 weeks. Multiple generations annually with generation time approximately 4–6 weeks.

Larvae exhibit characteristic looping locomotion due to reduced proleg number. When disturbed, larvae may drop from foliage on silk threads. Adults are nocturnal and strongly attracted to artificial light. Females oviposit preferentially on leaf undersides in upper or middle plant canopy.

Larvae function as primary consumers in agricultural and natural ecosystems. Several species are major crop pests causing significant yield losses through defoliation. Serve as hosts for diverse parasitoid wasps including Microplitis demolitor and Copidosoma floridanum. Prey for generalist predators including predatory stink bugs (Podisus maculiventris).

Several species are economically important agricultural pests. Chrysodeixis includens (soybean looper) is a major defoliator of soybean in the southern United States and increasingly in South America, with documented resistance to multiple chemical insecticide classes. C. chalcites (tomato looper) and C. eriosoma (green garden looper) damage vegetable crops. Management relies on integrated approaches including biological control, Bt-based products, and selective insecticides.

• RachiplusiaAlso in subfamily Plusiinae with three pairs of prolegs and looping larvae; distinguished by adult wing patterns and larval coloration (R. nu larvae often have darker, smoky-blue cast compared to bright yellow-green of C. includens)
• TrichoplusiaPlusiinae genus including cabbage looper (T. ni); larvae similar in form but distinguished by specific markings and geographic distribution
• Geometridae (true loopers)Larvae also loop but have only two pairs of prolegs (on abdominal segments 4–5) versus three pairs in Chrysodeixis; different family with different adult morphology

Larvae are often colloquially called 'inchworms' or 'measuring worms,' terms properly restricted to geometrid caterpillars with only two proleg pairs. The former genus name Pseudoplusia persists in older literature for C. includens, though this synonymy was formalized by Goater et al. (2003) and applied to North American fauna by Lafontaine and Schmidt (2010).

• agricultural pest
• soybean pest
• defoliator
• Plusiinae
• looper
• invasive species
• insecticide resistance

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Scientists Reveal New Method to Characterize Physiological Responses to Parasitism | Bug Squad
• ID Challenge #14 | Beetles In The Bush
• A Revision of Soybean Caterpillar Pest Information for U.S. Soybean
• Noctuidae | Beetles In The Bush | Page 2
• “Sunflower looper” – Rachiplusia nu | Beetles In The Bush
• owlet moths | Beetles In The Bush
• The Effects of Adjuvants on Steinernema Carpocapsae Efficacy Against Chrysodeixis Includens and Suspension Stability.