Spatial Analysis of Seasonal Dynamics and Overwintering of Drosophila suzukii (Diptera: Drosophilidae) in the Okanagan-Columbia Basin, 2010–2014

Abstract

Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), was monitored from 2010 to 2014 in 314-828 sites located in interior fruit-growing regions of OR and WA, United States, and BC, Canada, using traps baited with apple cider vinegar or sugar-water-yeast. Seasonal population dynamics and sex ratios were summarized for berry, cherry, stone fruit, grape, non-crop host plants, non-host sites, and for conventional IPM, certified organic, backyard, and feral sites, by region and year. Overwintering was detected in all regions and years, despite winter temperatures below -17°C. A spatial analysis was conducted using a Geographic Information System (GIS), daily weather data, geomorphometric measures of terrain, distance to water, and other variables, at each site. Overwintering success at a site, measured as Julian week of first capture of D. suzukii, was significantly related (R2 = 0.49) in cherry habitats to year, agronomic treatment, and number of winter days with temperatures>-5°C. In berry, cherry, stone fruit and grape habitats, 2011-2014, it was significantly related (R2 = 0.42) to year, agronomic treatment, the logarithm of peak population of D. suzukii in the prior autumn, latitude, elevation, and topographic wetness index. The results show that D. suzukii has adapted to exploit a succession of irrigated crops and feral habitats in mixed landscapes of a semi-arid region with cold winters and hot dry summers, and are shaping strategies for pest management and for biological control.

Spotted wing drosophila (Drosophila suzukii) utilization and dispersal from the wild host Asian bush honeysuckle (Lonicera spp.)

“…Drosophila suzukii was found commonly in five wild hosts that are present in the habitats surrounding blueberry fields in central and west‐central Michigan across two growing seasons (Table ). This pest is highly polyphagous and is known to utilize a variety of wild hosts, many of which were not found in the present study (Lee et al ., ; Poyet et al ., ; Briem et al ., ; Kenis et al ., ; Thistlewood et al ., ). We expect that the wild hosts sampled are only a fraction of the hosts available to D. suzukii in our landscape and these data do not represent the complete host range of wild fruits.…”

Influences of blackberry margins on population dynamics of Drosophila suzukii and grape infestation in adjacent vineyards

“…The sex ratio of D. suzukii flies shifted towards male‐biased and back to female‐biased captures throughout the season, which is partly in line with previous studies from other regions reporting a skewed sex ratio (Haviland et al, ; Rossi‐Stacconi et al, ; Tait et al, ). The female‐biased sex ratio particularly at the beginning and the end of the year may be related to a higher winter survival or longevity of females (Hamby et al, ; Thistlewood et al, ; Zerulla et al, ). During grape ripeness (period 3), the sex ratio switched towards a higher proportion of males in traps but not in vacuum captures (Supporting Information A4) of BB sites and was male‐biased at all sites in period 4.…”

Management strategies against Drosophila suzukii: insights into Swiss grape growers choices

“…The percentage above is an estimate based on 160,000 berries from 600 Swiss vineyards between mid‐August 2016 and October 2016, and thus does not represent the real damage suffered by grape growers in their vineyards . Overall, we find that infestation pressure and damage to growers are heterogeneous over time and space, and might also depend on the cultivation system . Susceptibility to infestation is also variety specific and depends mainly on skin hardness, sugar content and acidity levels .…”

“…46 Overall, we find that infestation pressure and damage to growers are heterogeneous over time and space, and might also depend on the cultivation system. 14,21,40,[47][48][49] Susceptibility to infestation is also variety specific 14,16 and depends mainly on skin hardness, 49 sugar content and acidity levels. 14 Grapes prone to damage might be more sensitive to D. suzukii than intact grapes, 50 in some cases red grapes are reported to be more attractive than white varieties 14,16,21,51 and the sensitivity of the grapes is higher when fully ripened.…”