Pacific Northwest Moths

Identification

Adults

Chrysodeixis chalcites is an introduced agricultural pest that occurred in greenhouses in southwestern British Columbia in 2005 and 2006. It is a medium-sized moth (FW length 17 mm) with gray-brown and warm brown wing color and silver stigma with a large oval spot. The forewing has a pointed apex, a dark-edged flange at the anal angle, and a toothed pattern in the fringe. The ground color is slightly mottled and slightly speckled gray-brown. The mid-base, most of the median area except the costa, the subterminal area near the anal angle, and the apical terminal area are warm golden-brown with a distinct sheen. The median area anterior to the stigma and the subterminal area opposite the cell are shaded darker brown. The stigma is often divided into two parts, a medial hook-shaped line and a large oval lateral spot. The lines are silver to light gray. The basal line is straight, present across the anterior two-thirds of the wing. The antemedial line is strongly oblique from the costal margin toward the outer margin, interrupted by the cell, and then strongly angled toward the base below the cell. It appears to be continuous with the proximal end of the stigma. The postmedial line is sinuous, oriented nearly straight across the forewing. The subterminal line is dark gray-brown but slightly diffuse, stronger and the anterior half of the forewing, irregularly scalloped and forming a "W" mark with the teeth below veins M2 and M3. The terminal line is pale on the anterior half of the wing and barely evident on the posterior part. The fringe is light gray with a scalloped median line, a small black dot on vein M2, and a dark apex. The orbicular and reniform spots and the median line are barely visible. The hindwing is brown-gray, gradually darker gray toward the margin, with dark gray veins and terminal line. The hindwing fringe is pale tan off-white with weak checkering. The head, collar, and median thorax are warm golden-brown, with strong tufting on the posterior thorax. The tegulae are gray-brown. Additional dorsal tufts are present on the anterior abdomen. The lateral abdomen of males bear additional pale buff tufts of very long scales, and black scales are present on the ventral distal portion. The male antenna is filiform.

This tropical species should not be expected in the Northwest except as a greenhouse pest. It is closely similar to the soybean looper Chrysodeixis includens, a very rare fall migrant to our area. The forewings of these species are nearly indistinguishable, but males of C. chalcites can be identified by the buff long buff scales on the sides of the abdomen as well as the black distal tuft, both lacking in C. includens. Trichoplusia ni has similar scales on the lateral abdomen, as well as a similar stigma, but it is mottled dull gray with reddish brown tufts.

The British Columbia infestation of this moth was referred to initially as Chrysodeixis eriosoma (Doubleday) until 2013, but the correct identity is C. chalcites (Lafontaine & Schmidt 2013). These very similar species are agricultural pests, but C. eriosoma is more common in eastern Asia and C. chalcites is more common in Africa and western Eurasia (Lafontaine & Schmidt op. cit.). The specimen here is C. eriosoma.

Habitat

This species occupies disturbed agricultural and urban habitats thoughout the tropical and subtropical regions of both North and South America, but migrates northward during the summer.  This species infested greenhouses in British Columbia in 2005 and 2006, now eradicated completely, and became so common that occasional specimens were encountered in the Vancouver area outside of greenhouses (D. Holden, pers. comm.).

Distribution

Pacific Northwest

Chrysodeixis chalcites is a tropical species that has only been found in and near greenhouses in southwestern British Columbia in our region. It did not become established in our temperate climate.

Global

This species is widespread in Africa and western Eurasia, appearing elsewhere in the world as an introduced pest.

Life History

Larvae

This species is a generalist feeding on many herbaceous plants. 

Adults

Chrysodeixis chalcites does not reproduce under natural conditions in our area. Most records from British Columbia were during fall (D. Holden pers. comm.).

Economic Importance

This species is a major agricultural pest in some parts of the world.

Literature

Powell & Opler (2009)

Lafontaine & Schmidt (2013)