POPULATION DYNAMICS OF DROSOPHYLA SUZUKII (MATSAMURA) IN SWEET AND SOUR CHERRY ORCHARDS IN THE CENTRAL BALKANS MOUNTAIN

The spotted wing drosophila (SWD) Drosophila suzukii, Matsumura is a polyphagous for many stone and soft fruits species. The pest was recorded in 2014 at sweet cherry orchards in our country and has become a real pest, because SWD attack the fruit when they start to ripe. During 2017-2019 the study was carried out in the Institute of Mountain Stockbreeding and Agriculture in Troyan – Central part of the Balkans Mountain. For monitoring were used traps with red wine and apple vinegar. The first flies at the sweet cherry were found during the second decade of May and in the sour cherry - a little later, at the beginning of June, when the fruit start to ripe. The peak of the population dynamics was established in the second half of June, after which the density began to decreasing. It was found that D. suzukii was preferred more the sweet cherry fruits than sour cherry fruits.

Development of spotted wing drosophila in fruits of two raspberry cultivars

Spotted wing drosophila (Drosophila suzukii (Matsumura, 1931)) a polyphagous alien invasive species causes economic damages in cultivation of soft fruits all over the word. It is widespread in Croatia and considering that the economic damage occurred in greenhouse cultivation of soft fruit several years ago, new damage in this production can be expected. The pest development was monitored on 50 overripe fruits of cultivars 'Amira' and 'Sugana' cultivated in greenhouses in Zagreb in 2018 to investigate pest preference for these cultivars and to make a risk assessment in raspberry cultivation. Pest presence was recorded on both cultivars at the same time, and D. suzukii was dominant drosophilid species in development. Significantly more drosophilids as well as individuals of D. suzukii were developed on cultivar 'Amira'. On 'Amira' 373 female and 211 male of D. suzukii developed, while on 'Sugana' 253 female and 142 males developed. Average number of pests per fruit on 'Amira' counted 11.68 and on 'Sugana' 7.9. Drosophila suzukii develops in high populations in the greenhouse production of raspberry cultivars, which poses a serious risk for their cultivation in the study site.

Spatial distribution of spotted-wing drosophila (Diptera: Drosophilidae) and other insects in fruit of a sweet cherry (Rosaceae) orchard

Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an invasive pest of many small and soft fruits. We present the first results concerning its oviposition in the canopy of a sweet cherry (Prunus avium Linnaeus; Rosaceae) orchard. We examined the distribution of arthropods emerging from fruits of five cultivars ripening successively over seven weeks, in interior and border rows, within four regions of the tree canopy (top/bottom height × north/south aspect), and measured the associated fruit ripeness (ºBrix). Single fruits were reared for more than two weeks: 1328 arthropods emerged from 887 cherries in June, and 10 426 emerged from 1071 cherries in July. When populations were low, significantly more D. suzukii were present in the northernmost row and northern canopy aspect. Later, its distribution with respect to cherry row, height, and aspect was homogenous. Drosophila suzukii density per sweet cherry was highest in the latest ripening cultivar, when its distribution was not homogeneous; significantly more D. suzukii were in the centre than the southernmost row, in the lower canopy, and the southern aspect, than elsewhere. In the early season, single egg clutches were found without aggregation. As population density increased, so did intraspecific aggregation, but D. suzukii did not co-exist with other Drosophila Fallén species, nor with Rhagoletis indifferens Curran (Diptera: Tephritidae) when present.