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Calophasia lunula (Hufnagel)
(Lepidoptera: Noctuidae)

by Rich Hansen, USDA-APHIS-PPQ, Forestry Sciences Lab, Montana State University, Bozeman, MT 59717-0278.

Calophasia lunula was introduced in Canada beginning in the early 1960s; US releases were initiated in 1968. Populations are established on yellow toadflax in eastern Canada and on yellow and Dalmatian toadflax in several northwestern US states and British Columbia. (Background information about Dalmation toadflax and yellow toadflax is available.)

Appearance

C. lunula adults are grey moths with various dark and light wing markings. Moths are about 12-14 mm long, with a wingspan of about 27-30 mm. Moths are inactive during the day, resting on vegetation, but become active at night and feed on nectar from various flowers, including those of toadflax.

Young larvae are 2-3 mm long and pale grey in color. Older larvae have longitudinal yellow, black, and grey stripes with black and white spots, and may reach a length of 35 mm at maturity. Larvae feed on leaves of Dalmatian and yellow toadflax and are active during the day.

Pupae are 14-15 mm long, reddish-brown in color, and contained within white silk cocoons that include soil particles and/or plant debris. Cocoons are usually found on the soil surface or attached to the lower part of plant stems.

Habitat

Grasslands, pastures, agricultural fields, and roadsides infested with yellow or Dalmatian toadflax.

Pests attacked

C. lunula feeds on both Dalmatian and yellow toadflax. Host specificity appears restricted to species in several genera of the family Scrophulariaceae.

Life cycle

Adult moths first eclose in late spring and live for several days to more than a week. After mating, females lay eggs individually on toadflax leaves; each female generally lays a total of 30-80 eggs.

Larvae feed on toadflax foliage, at first skeletonizing leaves but later consuming entire leaves. Generally, larvae preferentially feed upon young foliage, but older leaves and flowers are consumed in the absence of young leaves. There are five larval stages. Mature larvae crawl down toadflax stems and construct a silk cocoon into which soil, plant fragments, or frass are added, and then pupate.

Cocooning usually occurs on the soil surface or at the base of a toadflax stem. There are one to three generations per year, depending on weather conditions, with winter spent in the pupal stage.

Relative effectiveness

Calophasia lunula larvae can cause significant defoliation of toadflax plants when populations are large. Though direct plant mortality does not usually occur, defoliated plants generally produce fewer flowers and seeds and may produce fewer nutrients for root storage. However, long-term effects on weed density remain poorly understood.

Pesticide susceptibility

Unknown.

Conservation

Specifics are unknown. For general information about conservation of natural enemies, see Conservation in the Tutorial section on this site, Feature Article on conservation in Volume II, No. 1 of Midwest Biological Control News.

Commercial availability

Calophasia lunula may be available from several state weed management agencies.

References

Harris, P. 1963. Host specificity of Calophasia lunula (Hufn.) (Lepidoptera: Noctuidae). Can. Entomol. 95: 101-105.

McClay, A.S. and R.B. Hughes. 1995. Effects of temperature on development rate, distribution, and establishment of Calophasia lunula (Lepidoptera: Noctuidae), a biocontrol agent for toadflax (Linaria spp.). Biol. Control 5: 368-377

McDermott, G.J., R.M. Nowierski, and J.M. Story. 1990. First report of establishment of Calophasia lunula Hufn. (Lepidoptera: Noctuidae) on Dalmatian toadflax, Linaria genistifolia ssp. dalmatica (L.) Maire and Petitmengin, in North America. Can. Entomol. 122: 767-768.

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