Phorbia

Agricultural fields, particularly cereal and onion crops. Phorbia coarctata prefers potato, swede, and sugar beet fields for oviposition. Phorbia securis infests cereal crops in semi-arid zones. Some species associate with Epichloe-infected grasses.

Europe and Northern America. Documented in Denmark, Norway, and Sweden. Phorbia securis occurs in Morocco (Chaouia, Doukkala, and Abda regions).

Phorbia coarctata: egg laying begins late June, peaks in July, ends in August. Main flight activity occurs in afternoon and evening until nightfall. Phorbia securis: two generations per year; first generation infests wheat from emergence, second generation infests young tillering wheat at end of February and beginning of March.

Larvae feed on plant roots and stems. Phorbia coarctata larvae feed on wheat and other cereals. Phorbia cepetorum larvae feed on onion plants (Allium cepa). Phorbia securis larvae attack cereal stems, with highest damage to stems 14–20 cm long.

• Triticum (wheat) - larval food sourcePhorbia coarctata and Phorbia securis
• Allium cepa (onion) - larval food sourcePhorbia cepetorum
• Solanum tuberosum (potato) - oviposition sitePhorbia coarctata
• Brassica napus (swede, rapeseed) - oviposition sitePhorbia coarctata
• Beta vulgaris (sugar beet, fodder beet) - oviposition sitePhorbia coarctata
• Epichloe (fungus) - mutualistic spore dispersalFlies transport spermatia between fungal individuals; interaction ranges from mutualistic to parasitic

Complete metamorphosis with egg, larva, pupa, and adult stages. Phorbia securis has two generations per year. Phorbia coarctata eggs are laid on soil; larvae migrate to host plant roots. Pupation occurs in soil.

Adult females preferentially oviposit on rough soil surfaces and in closed crop stands rather than open areas. Phorbia coarctata females deposit more eggs on dry soil than moist soil, and egg laying increases with declining light intensity. Artificial soil elevations attract more eggs on north-facing sides. Flies exhibit specific behaviors ensuring cross-fertilization of Epichloe fungi, analogous to pollinator behavior in angiosperms. Males and females show differential attraction to fallow traps, with females more strongly attracted.

Agricultural pest causing serious damage to cereal and onion crops. Vector for Epichloe fungal reproduction, providing ecological service analogous to pollination. Some species act as pollinating seed parasites in convergent evolutionary system with fungi.

Several species are economically significant crop pests requiring monitoring and control. Phorbia coarctata and Phorbia securis damage wheat and cereals; Phorbia cepetorum damages onions. Control methods include poisoned bait sprays. Phorbia securis reached damaging levels in 20% of surveyed Moroccan cereal fields.

• DeliaBoth genera in Anthomyiidae contain agricultural root maggot pests; Delia includes onion fly (D. antiqua) and cabbage root fly (D. radicum), which overlap with Phorbia in host use and habitat. Delia species generally have more pronounced bristle patterns on the thorax.
• HylemyaAnother anthomyiid genus with similar general morphology and agricultural pest species. Hylemya species often lack the distinct wing vein characteristics and abdominal coloration patterns seen in Phorbia.

• Agricultural pest
• Root maggot
• Cereal pest
• Onion pest
• Fungal mutualism
• Pollination analog
• Convergent evolution

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Surveillance de l'infestation des céréales par la mouche noire (Phorbia securis Tiensu ; Diptera, Anthomyiidae)
• Mutualistic and parasitic interactions betweenPhorbiaflies andEpichloe: convergence between a fungus and entomophilous angiosperms
• Life History, Natural Enemies and the Poisoned Bait Spray as a Method of Control of the imported Onion Fly (Phorbia Cepetorum Meade) with notes on other Onion Pests1
• Beitrag zur Frage der Eiablage der Brachfliege (Phorbia coarctata Fall.) auf Kulturflächen, künstlicher Brache und im Laboratorium sowie ihres Fluges im Freien1