Rhagoletis cerasi (European Cherry Fruit Fly) - Fact sheet

Background

The European cherry fruit fly (Rhagoletis cerasi L.) is the most serious pest of cherries in Europe. Damage associated with this pest is caused by larval feeding in the fruit pulp, which can result in losses of up to 100% if left uncontrolled. This pest may be introduced to new areas with fresh cherries or with soil or fruit from host plants grown in areas where this pest occurs. The presence of this pest in Canada was confirmed for the first time in June 2016 in an urban park located in Mississauga, Ontario. This is the first record of this fly in North America.

Plant pest card - European Cherry Fruit Fly

Hosts

Literature from Europe suggests the principle host is Prunus spp., including sweet cherry (P. avium), sour cherry (P. cerasus), black cherry (P. serotina) and mahaleb cherry (P. mahaleb). Honeysuckle hosts documented in Europe include Lonicera xylosteum, L. tartarica, and L. alpigena. In Ontario, adult detections have been in association with Lonicera spp., including L. morrowii, L. tartarica, and L. xbella. This species attacks the fruit of its host plants but no other part of the plant.

Distribution

This species is currently found in:

• Asia: in temperate regions of Asia, including areas of the Middle East and Central Asia
• Canada: Ontario
• Europe: most of Europe, except the British Isles
• United States: New York

Biology

The European cherry fruit fly has only 1 generation per year, with a long winter diapause during the pupal stage. This obligatory winter diapause usually lasts around 180 days but some pupae may remain dormant over 1, 2 or even 3 winters. Pupae overwinter in the soil, mainly underneath or near the host plant, and require temperatures of 7°C or lower to develop successfully. Adults typically emerge in the spring, usually appearing from May to July and have an average lifespan of 2 weeks. Females usually deposit 1 egg per fruit, beneath the skin of the fruit. Once larvae hatch from the eggs, they develop inside the fruit where they feed for up to 6 weeks. As the larvae develop, they damage the fruit pulp and contaminate the fruit with their feces, making infested fruit unacceptable for fresh consumption. Mature larvae exit the fruit through emergence holes and drop to the ground to burrow into the soil, generally at a depth of approximately 1 to 13 cm. Once in the soil, they will pupate within a few days.

Detection and identification

Symptoms: attacked cherry fruits are pitted with oviposition puncture marks and the tissue surrounding these punctures will appear soft and brownish. Brown rotten spots on cherry fruits may also be noticeable when the larva inside is fully grown. Exit holes are visible on cherries that larvae have vacated (Fig. 1). Cutting into fruit may also reveal larvae and internal feeding damage, evident due to characteristic tunneling.

Identification: the adult is small (3.5–4.0 mm length) and both males and females are predominantly black in colour (Figs. 2–3). The wings are transparent, with characteristic dark crossbands. The scutellum of the thorax is entirely yellow, lacking a black basal mark. There are three larval instars of this species and the third larval instar is medium sized (5–6 mm length; 1.2–1.5 mm width) and white or yellowish in colour. The head (anterior end) has projecting and heavily sclerotized mouth-hooks and the thoracic and abdominal segments have rows of spinules, including large anal lobes. The pupa is almost identical in appearance to the third larval instar, as the puparium is the hardened skin of this larval instar (Fig. 4).