Pacific Northwest Moths

Identification

Adults

Chrysodeixis includens, the soybean looper, is a rare fall migrant to the Pacific Northwest. It is a medium-size moth (FW length 15–17 mm) with a mottled gray and warm brown forewing with patchy golden sheen marked by silver lines and stigma. The forewing is pointed with a concave posterior margin that ends in a slight flange at the anal angle. It is mottled medium gray, dull gray brown, brown, and has a mottled brassy or golden sheen on the posterior medial area, between the reniform spot and postmedial line, and on the mid-wing distal to the postmedial line. The anterior half of the basal line, all but the most anterior segment of the antemedial line, and the postmedial line at the posterior margin are thin lustrous silver. The silver stigma is bipartite, an open loop (possibly part of the orbicular spot) joined to the antemedial line and a separate solid spot adjacent to the distal end of the loop. The postmedial line is faint, occasionally a thin lustrous line but typically evident only as the transition between different mottled shades in the medial and postmedial areas. The subterminal line is irregular with a weak W-mark on the mid-wing, lustrous brown. The fringe is weakly checkered gray and brown except a dark gray spot on vein M2 adjacent to a dark brown spot in the terminal area. The hindwing is dull gray brown with slightly darker veins and thin discal spot. The hindwing fringe is tricolored, yellow at the base, dark gray, and white edged. The head and thorax are similar brown to the forewing. There are strong dorsal tufts on the thorax and abdomen. The male antenna is filiform.

This species and Chrysodeixis chalcites are closely similar in appearance. Females cannot be distinguished reliably by superficial appearance but males of C. chalcites have black tufts on the distal abdomen that C. includens males lack. Neither species is native to the Pacific Northwest nor established permanently. Chrysodeixis chalcites was a greenhouse pest in southern mainland British Columbia but is now eradicated. Any Chrysodeixis found outside of a greenhouse setting in our region is most likely C. includens. The shape of the silver stigma of Trichoplusia ni is similar to that of C. includens, but this moth appears dull mottled brownish gray rather than shiny warm brown like C. includens and males have distinctive red brown abdominal tufts.

Larvae

Habitat

This moth is most likely to be found in an agricultural setting in the Pacific Northwest. It probably reaches our area as a migrant and could be therefore be encountered in almost any low elevation habitat.

Distribution

Pacific Northwest

Chrysodeixis includens has only been found once in the Pacific Northwest, in LaGrande in northeastern Oregon.

Global

This species is common and widespread in much of southern United States, with migrants reaching southeastern Canada. It occurs in California, with most records from the central and southern parts of the state.

Life History

Larvae

The larva is the soybean looper, a catholic feeder on many dicot plants.

Adults

This species has only been encountered once during October in the Pacific Northwest. It can be found throughout most of the year in the south, including in California, but is most commonly encountered during late summer and fall towards the northern part of its range. Adults and early stages of this tropical species are killed by freezing.

Economic Importance

Significant. The diet of this moth includes many agricultural crops. The common name, soybean looper, refers to the damage that the larvae can cause on this crop.

Literature

BugGuide

Moth Photographers Group