Chrysodeixis

Hübner, 1821

Chrysodeixis is a of ( , Plusiinae) described by Jacob in 1821. The genus contains approximately 30 described distributed across the Americas, Asia, and Oceania. Several species are significant agricultural pests, particularly Chrysodeixis includens (soybean ) and C. chalcites (tomato looper), which cause damage to legume and solanaceous . are characterized by having three pairs of and a distinctive looping .

Chrysodeixis by (c) John Tann, some rights reserved (CC BY). Used under a CC-BY license.

Chrysodeixis by (c) Jon Sullivan, some rights reserved (CC BY). Used under a CC-BY license.

Chrysodeixis includens P1130272a by
xpda. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Chrysodeixis: /ˌkɹɪsoʊˈdeɪksɪs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

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

Images

Habitat

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

Distribution

Widespread across North America, Central and South America, Europe, Asia, Africa, and Oceania. Individual 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.

Seasonality

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

Diet

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

Life Cycle

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

Behavior

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

Ecological Role

function as primary consumers in agricultural and natural . Several are major pests causing significant yield losses through . Serve as for diverse including Microplitis demolitor and Copidosoma floridanum. for including (Podisus maculiventris).

Human Relevance

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

Similar Taxa

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

Misconceptions

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

More Details

Taxonomic History

The Pseudoplusia was synonymized under Chrysodeixis by Goater et al. (2003), with this synonymy formally applied to North by Lafontaine and Schmidt (2010). C. includens was long known as Pseudoplusia includens in North American literature.

Insecticide Resistance

Chrysodeixis includens has developed documented to multiple including , , and , driving interest in alternatives such as nematodes.