Atherigona orientalis, a highly polyphagous and unregulated pest fly
At the 29th meeting of EFSA's Scientific Network on Emerging Risks, the following potentially emerging risk was brought to the attention of the DFI. Atherigona orientalis a pantropical and unregulated species, has recently been reported in mainland Spain, France, and Greece. The species has been intercepted multiple times during import controls in France on shipment originating from tropical countries.

This species is highly polyphagous, feeding on living and decaying plant materials, dung, carrion, and other insects. It has been identified as a primary pest in several crops, with a notable impact on Solanaceae and Cucurbitaceae plants. A. orientalis exhibits a short life cycle and a high intrinsic growth rate, leading to rapid population growth.

There are concerns for human health as a potential vector of faecal pathogens and filth-borne diseases.

From a phytosanitary point of view, this species is currently of low risk in central and northern European countries, where its occurrence is expected to be limited to indoor environments (e.g. greenhouses). However, in southern European countries, the risk is assessed as medium, as there is a potential for outdoor occurrence.

The presence and spread of A. orientalis highlight the need for appropriate management strategies. The potential impact on agriculture, the risk to human health, and the phytosanitary concerns associated with this species necessitate continued monitoring and preventive measures to mitigate its occurrence and minimize its potential negative effects on both crops and public health.

First report in France

In October 2022, the first report of pepper fruit fly was made in south-west France, in Sollies-Toucas. The discovery involved the collection of four larvae from peppers (Capsicum annuum). It represents the initial documented instance of this species in the region. It is worth noting that a suspicion regarding the presence of this species had been raised in 2013. However, confirmation of this suspicion is still pending. This particular species has been intercepted 18 times in France during import controls since 2000. These perceptions occurred through various pathways, but the primary on Solanaceous fruits that originated from tropical regions.

Taxomony, morphology and life cycle

The pepper fruit fly (Atherigona orientalis Schiner, 1868) belongs to the subgenus Acritochaeta of the genus Atherigona of the family Muscidae, whose members are distributed throughout the tropical and subtropical regions of the world. The members of the Architochaeta subgenus are mostly saprophagous, with larvae living in various types of decaying organic matter. The pepper fruit fly is the sole known member of the subgenus that holds economic significance.

Adults are small, possess an angular head, typically gray or yellowish-gray in colour. The larvae progress through three larval stages and possess several posterior and anterior spiracles. Under laboratory conditions, the rearing time from egg to adult ranges between 23.5 and 30.0 days. However, at slightly lower temperatures, this duration shortens to 18.6 days. Oviposition sites are predominantly found on the calyx and groove of Capsicum spp. Infested fruits, or the soil serve as locations for pupation to occur.

<em>Atherigona orientalis</em>. Credit: Gary Steck, Florida Department of Agriculture and Consumer Services, Division of Plant Industry, <a href=
Atherigona orientalis. Credit: Gary Steck, Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Source

Host plants and diversity

This species feeding on various living and decaying plant materials, faeces, and carrion. Such adaptability allows this species to develop on a wide range of substrates, making it of significant importance in forensic, sanitary, and phytosanitary contexts.

In terms of sanitary importance, there is a potential association with the transmission of faecal pathogens and diseases carried by filth. Moreover, when it comes to plant health concerns, this species primarily functions as a saprophagous organism but can also become a primary pest for certain crops. It has a diverse range of host plants, including Solanaceae (such as pepper, tomato, and eggplant), Brassicaceae (like cauliflower), Fabaceae (including beans), Cucurbitaceae (such as cucumber and melon), Poaceae (including sorghum, wheat, and corn), Rutaceae (including oranges, grapefruits, and mandarins), Liliaceae (garlic), Apiaceae (carrots), Rosaceae (peaches), and many others. This wide host range encompasses at least 25 different plant families commonly found in agricultural, vegetable, and fruit crops.

Economic significance and current regulation

There have been many reports of damage inflicted on various host plants in different countries. In Nigeria, A. orientalis has emerged as a major pest of bell peppers (Capsicum annuum), with infestation levels reaching as high as 51%. In Pakistan, infestation rates ranging from 25% to 85% on melon fruits (Cucumis melo). In Australia and India A. orientalis is the primary pest of tomatoes.

In Europe, reports indicated some damage to commercial pepper crops in Greece, although the extent of the impact in France remains uncertain due to insufficient information. Considering the potential risks associated with A. orientalis, it is listed as a quarantine pest in Korea and New Zealand. However, there are no specific regulations in place for its management in other countries.

Risk assessment for Europe

A. orientalis demonstrates varying patterns of risk across different regions in Europe. In central and northern Europe, the species is not expected to cause significant damage, except in the case of strong occurrences, where damage may be observed on peppers and tomatoes cultivated in greenhouses. However, in southern Europe, particularly in Mediterranean countries, A. orientalis has the potential to occur outdoors, posing a medium phytosanitary risk.

Recent reports from Europe, including Spain in 2017 and France and Greece in 2022, have raised concerns about the emergence of this pest.


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