Drosophila suzukii (Diptera: Drosophilidae): A pest species new to Belgium

Short notes don’t have an abstract.

On 21 September, 2011, a single male of the spotted wing drosophila, Drosophila suzukii, was captured in Ostend, Belgium (altitude 4 m ab.s. l.).This highly fecund species differs from most other members of the Drosophilidae in its ability to infect healthy ripening fruit instead of overripe, rotting fruit (1).D. suzukii can infect healthy softbodied fruit such as blueberries, blackberries, raspberries, cherries, or strawberries, and can even infect hard fruit such as apples and pears (4).After infestation, secondary parasites and invaders, such as Drosophila melanogaster, Nitidulidae, Botrytis and Rhizopus spp.often contribute to further fruit deterioration.These characteristics make D. suzukii an economically important pest species that requires management to the full extent possible.
The first reported detection of D. suzukii in europe was in 2008 in Rasquera, Spain (1).Until late 2011, european detection of D. suzukii had been limited to dry Mediterranean climates.Now, together with observations in Germany, also in autumn 2011 (6,7), the discovery in Belgium is of great importance since these are the first records of the species in the more temperate northwesteuropean regions.ecological simulations seem to indicate that those Mediterranean conditions are not optimal for the growth of D. suzukii (2).Up to now, the only report of crop damage in europe due to D. suzukii was the publication of Lee et al. (2011), who reported crop destructions of up to 80% in Trentino, Italy.However, Hauser (2009) suggested that D. suzukii could develop into a serious pest in the more humid northwest european areas.
Several reports of D. suzukii in europe can be found on the Internet, but published literature is scarce.After its detection in 2008 in Spain, the species was found in 2009 in several southern european areas: southern France (Montpellier, Languedoc-Roussillon, Provence-Alpes-Côte d'Azur, Corsica, Alpes-Maritimes), Spain (Barcelona) and Italy (Piemonte, Trentino, Tuscany).
Unconfirmed records from Portugal were made available through a media report (1,9,10).In 2010, the fly was reported in Slovenia (11).The first northern European report was from HendricH et al. ( 2012), who mentioned first sightings of the species in the German provinces Baden-Württemberg, Bavaria and Rhineland-Palatinate in 2011.Recently, D. suzukii was detected in the Swiss locations of Graubünden and Tessin (12), and in Austria (11).
The species seems to spread rapidly across the european mainland in a similar manner to the extensive and rapid spread across North America.Adults are highly mobile within a local area, but long-distance dispersal probably occurs via transport of infected fruit.The D. suzukii fly detected in Ostend, Belgium could have been imported with infected fruit from the nearby harbour in Zeebrugge.The Belgian authorities are vigilant for the presence of the fly and rely on the Institute for Agricultural and Fisheries Research (ILVO, Plant Sciences Unit -Crop Protection research area) for information about the presence of this species in Belgium.The Belgian Federal Agency for the Safety of the Food Chain (FASFC) will perform a quickscan monitoring program in 2012 to determine whether D. suzukii is settling in Belgium.In addition, the Belgian fruit research center (pcfruit) plans to investigate the potential spread and phytosanitary impact of Fig. 1. -Detail of the male tarsal combs.D. suzukii in the major fruit growing regions of Belgium (13).Traps with attractants to gather D. suzukii were put on the market in February 2012 (14).This monitoring is crucial because quick intervention can prevent crop damage and further spread of the pest.Damage can be prevented by immediately removing the flies and physically destroying infested fruit as fast as possible (4).
The spotted wing drosophila is easy to identify.Males can be identified based on the spots in the tip of their wing and the two sets of tarsal combs.Females have a long and narrow ovipositor with many dark sclerotized teeth (15).Further information on identification can be found in Hauser (2011).In Figures 1 & 2, the habitus of the male and the typical tarsal combs are illustrated.
All observations of D. suzukii (even in cases of doubt) should be reported to the corresponding author listed above, to the authorities, and to the research centers as quickly as possible.