Agapeta zoegana

(Linnaeus, 1767)

sulphur knapweed moth, yellow-winged knapweed root moth, knapweed root moth

A small, bright yellow native to Eurasia, introduced to North America in the 1980s as a agent for knapweeds (Centaurea maculosa and C. diffusa). The larva is a root miner that tunnels through the root cortex, causing moderate to considerable damage to plants. are short-lived, with activity from May to August. The has established in western North America and is compatible with other knapweed biocontrol agents.

Agapeta zoegana (24853584037) by gailhampshire from Cradley, Malvern, U.K. Used under a CC BY 2.0 license.

Agapeta zoegana (51290692289) by Ben Sale from Stevenage, UK. Used under a CC BY 2.0 license.

Agapeta zoegana - Flickr - Bennyboymothman by Ben Sale from UK. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Agapeta zoegana: /ˌæɡəˈpiːtə zoʊˈɡɑːnə/

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

Identification

Bright yellow forewings with distinct brown terminal blotch and costal markings; dark grey hindwings. Distinguished from similar tortricids by the combination of yellow ground color with ferruginous-fuscous patterning and association with knapweed . Z-11-tetradecenyl acetate is a documented sex attractant for monitoring.

Images

Appearance

are bright yellow with brown markings. Forewings have a moderately arched , with the costal edge, a small spot before the middle, and a large terminal blotch with angulated edge in ferruginous-fuscous brown. Hindwings are dark grey. Body length approximately 11 mm.

Habitat

Open, disturbed supporting knapweed . In native range, occurs in areas with Centaurea . In introduced range, established in spotted and diffuse knapweed in western and west-central North America. Larval habitat is within the root crown and root cortex of plants.

Distribution

Native to Eurasia, widely distributed across central and southeastern Europe including eastern Austria, northwestern Hungary, central Hungary, and Alsace region. Introduced to North America starting in 1980s; established in western and west-central United States and southwestern Canada (British Columbia since 1984).

Seasonality

from May to August, with peak varying by cohort and release . Emergence occurs from dusk and adults are attracted to light. Overwinters as larva in root.

Diet

Larva feeds on root tissues: early instars mine epidermal tissues of the root crown; older instars tunnel through root cortex and endodermis. plants are restricted to Centaurea , particularly spotted knapweed (Centaurea maculosa) and diffuse knapweed (C. diffusa).

Host Associations

Centaurea maculosa - primary tetraploid North American form is main target for biocontrol
Centaurea diffusa - primary ; established on in British Columbia since 1984
Centaurea vallesiaca - documented in European literature

Life Cycle

laid on stems and leaves. Larva mines root crown , then moves to root and tunnels through cortex; can migrate below ground to new if initial plant destroyed. Overwinters as larva within root. occurs in root; June through August. Several per year may occur. Adult lives only a few days.

Behavior

fly from dusk and are attracted to light. Larvae exhibit active searching ability and can migrate underground to locate new plants when initial host is destroyed. Under high larval densities, earlier and may occur, possibly due to resource depletion or crowding.

Ecological Role

Root herbivore and agent for knapweeds. Reduces knapweed spread in areas where mechanical and chemical control is impractical. Predominantly attacks rosette stage, which is the most sensitive stage for knapweed . Compatible with other knapweed biocontrol agents including Pelochrista medullana and seed-feeding .

Human Relevance

Intentionally introduced to North America for of noxious knapweeds. Approved for release in Canada and USA. Monitored using synthetic sex attractant (Z-11-tetradecenyl acetate). Reduces knapweed below in rangeland and pasture systems.

Similar Taxa

Pelochrista medullanaAnother knapweed root-feeding in Tortricidae; co-occurs in biocontrol programs but distinguished by different and
Other Cochylidae/TortricidaeAgapeta zoegana distinguished by bright yellow coloration with brown terminal blotch, specific association with Centaurea, and documented chemistry

More Details

Biocontrol efficacy

Optimal production achieved with releases greater than 1.6 male-female pairs per spotted knapweed plant. Larval densities in native range reach 23.6 larvae per 100 roots in eastern Austria/northwestern Hungary.

Taxonomic note

placement has been cited as both Tortricidae and Cochylidae in literature; currently accepted in Tortricidae ( Tortricinae, tribe Cochylini).