Euxesta

Loew, 1868

Cornsilk Flies

Species Guides

Euxesta is a of picture-winged flies in the Ulidiidae, commonly known as cornsilk flies. Multiple are significant agricultural pests of sweet corn (Zea mays), particularly in Florida, the southeastern United States, Mexico, Argentina, and Brazil. The genus includes at least four species documented attacking corn in Florida: E. stigmatias, E. eluta, E. annonae, and E. mazorca. Larvae develop within corn ears, feeding on silks and kernels and causing direct crop damage, often in association with secondary fungal .

Euxesta by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.

Euxesta quaternaria by (c) Sara Piotter, some rights reserved (CC BY), uploaded by Sara Piotter. Used under a CC-BY license.

Euxesta pechumani by (c) carnifex, some rights reserved (CC BY), uploaded by carnifex. Used under a CC-BY license.

Pronunciation

How to pronounce Euxesta: /juːkˈsɛstə/

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

Identification

Medium to dark metallic green to black flies with distinctive wing patterns typical of picture-winged flies (Ulidiidae). exhibit characteristic wing flapping . -level identification requires examination of wing venation patterns and genitalic structures; E. stigmatias and E. eluta are the most commonly encountered pest species in North American corn production.

Images

Habitat

Agricultural areas, particularly sweet corn fields during the reproductive (silking) stage. rest on corn leaves, tassels, and silks. Larval development occurs within corn ears and on rotting plant material. takes place in soil, with depth influenced by substrate type and moisture levels.

Distribution

North, Central, and South America in warm temperate and tropical regions. Documented in Florida (USA), Puerto Rico, Mexico, Guatemala, Argentina, Ecuador, Chile, and Brazil. Specific distributions vary: E. stigmatias primarily in the southeastern United States; E. eluta in Florida, Argentina, and Brazil; E. mazorca in Brazil.

Diet

Larvae feed on corn silks, pollen, and developing kernels within corn ears; also develop on rotting plant material including agave leaves. feed on nectar, plant exudates, and sources. Laboratory colonies maintained on sugar water and protein sources.

Host Associations

Zea mays (sweet corn) - primary — oviposition on cornsilk, larval development within corn earMajor economic pest; causes direct damage to kernels and secondary fungal establishment
Agave atrovirens - developmental E. bilimeki develops on rotting agave leaves in Mexican altiplano

Life Cycle

Complete : , larva, pupa, . Eggs laid on corn silks. Larvae develop within corn ears or on rotting plant substrates, often in . Developed larvae leave cobs and pupate in soil; depth varies with soil type and moisture, shallower under dry or saturated conditions. Multiple per year in favorable climates; multivoltine can overwinter at temperatures below freezing.

Behavior

attracted to corn specifically during the silking stage. E. eluta exhibits distinctive visual attraction : attracted to yellow at all brightness levels, to blue at mid-level brightness only, and not attracted to green. E. bilimeki males engage in visual and tactile , with frequent female rejection; females mate multiply and often expel and consume ejaculates after mating. depth increases in presence of root-like structures.

Ecological Role

Agricultural pest causing significant economic damage to sweet corn production; can cause greater than 20% ear damage in untreated fields. Normally saprophytic lifestyle on decaying plant material, but shifts to herbivory on corn reproductive structures. Serves as for pupal (Spalangia spp., Muscidifurax spp., Nasonia vitripennis) and larval parasitoids (Figitidae: Eucoilinae).

Human Relevance

Serious economic pest of fresh market sweet corn requiring including applications, agents, and trap development. Enhanced trapping strategies target -specific color preferences. Commercially available pupal used for filth fly control show potential for field application against cornsilk flies.

Similar Taxa

Chaetopsis massylaAlso a cornsilk fly pest of sweet corn in Florida; distinguished by behavioral attraction to yellow and green visual stimuli (avoiding blue), whereas E. eluta is attracted to yellow and blue but not green; requires examination of wing patterns and genitalia for definitive identification
Eumecosommyia nubilaPart of the cornsilk fly pest complex in Mexico; similar and damage on corn