Euxesta stigmatias

Distinguished from other corn-attacking ulidiids by combination of dark metallic green to black body coloration and specific wing pattern markings. In Florida, may be confused with three other cornsilk fly species: Chaetopsis massyla, Euxesta annonae, and Euxesta eluta. Wing pattern and dark metallic coloration help separate it from these sympatric species. Characteristic wing-flapping behavior provides additional field recognition cue.

Medium-sized fly with dark metallic green to black body coloration. Wings display distinctive patterned markings characteristic of picture-winged flies (family Ulidiidae). Exhibits a characteristic wing-flapping behavior when at rest.

Agricultural landscapes dominated by maize cultivation. In native range, tropical and subtropical corn-growing regions. In invaded range, established in southern Florida agricultural communities and Hawaii. Development occurs specifically within corn ears during fructification and grain maturation stages.

Native to tropical and subtropical regions of the Americas. Established in Florida, USA (invasive); recorded from Hawaii, USA; Galápagos Islands. Documented in Mexico (Sinaloa), Puerto Rico, Argentina, Ecuador, and Guatemala. Range expanding in North America.

Active during corn growing seasons. In Sinaloa, Mexico, observed during spring-summer agricultural cycle (March-July), with peak activity during fructification and grain maturation stages. In Florida, present throughout the year in agricultural communities with overlapping corn production cycles.

Larvae feed on maize silk and developing kernels, causing direct damage and associated fungal rot. Adults normally saprophytic, feeding on decaying organic matter; shift to corn ears when available.

• Zea mays - primary hostSweet corn and maize; larval development occurs within ears
• Spodoptera frugiperda - indirect associationFall armyworm damage to corn attracts ovipositing females
• Helicoverpa zea - indirect associationCorn earworm damage attracts flies

Eggs laid on or near corn silk. Larvae develop inside corn ears (elotes/grains), feeding on silk and kernels while protected within leaf wrapping. Pupation occurs in pupal chambers formed within corn ear leaf tissue or surrounding debris. Multiple generations per year possible in suitable climates.

Exhibits distinctive wing-flapping behavior when at rest. Females attracted to corn ears, particularly those with pre-existing damage from lepidopteran pests. Larval development occurs within protective corn ear structure, rendering larvae inaccessible to contact insecticides. Adults normally saprophytic, shifting to corn ears when available.

Agricultural pest causing direct feeding damage and facilitating secondary fungal infections that reduce grain quality and yield. Serves as host for natural enemies including parasitoid wasps (Spalangia spp., Pteromalidae; Eurytomidae) and predators (Orius insidiosus, coccinellids, syrphids, chrysopids). Potential host for entomopathogenic nematodes (Rhabditidae).

Major economic pest of sweet corn and maize production. Entire fields may be rejected for harvest if untreated or if treatments are missed due to weather or timing constraints. Invasive status in North America requires ongoing management. Subject to biological control research using native parasitoids and predators.

• Euxesta elutaAlso attacks corn in Florida; distinguished by wing pattern and coloration differences
• Euxesta annonaeCorn pest in Florida; similar habitat use but distinguishable by wing markings
• Chaetopsis massylaMember of cornsilk fly pest complex in Florida and Mexico; different genus but similar ecological role and damage symptoms

• agricultural pest
• invasive species
• maize pest
• picture-winged fly
• corn silk fly
• Diptera
• Ulidiidae
• North America invasive
• tropical agriculture
• subtropical agriculture

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• Cornsilk Fly (suggested common name), Euxesta stigmatias Loew (Insecta: Diptera: Otitidae)
• Cornsilk Fly (suggested common name), Euxesta stigmatias Loew (Insecta: Diptera: Otitidae)
• Enemigos naturales de las moscas de los estigmas del maíz: Euxesta stigmatias (Loew), Chaetopsis massyla (Walker) y Eumecosommyia nubila (Wiedemann) en Guasave Sinaloa, México