Spotted wing Drosophila, Drosophila suzukii (Matsumura) or SWD, is a newly significant worldwide pest of berries and stonefruits, with adverse economic effects having been reported in its native continent of Asia, the Americas, and Europe, of particular concern is the rate of SWD's global spread.
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In the review scientists report the current global distribution and economic impacts of SWD, biology and current pest status in endemic and recently invaded regions, developed models for predicting its further spread, and discuss the prospects for biological control of this pest in invaded habitats, with emphasis on the role of hymenopteran parasitoids.
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The rapid spread of SWD across Europe parallels the situation observed in North America. The authors describe the current state of SWD spread and management practices throughout invaded regions of North America and Europe, but several pivotal questions remain. They suggest at least three priorities for future work that will improve the accuracy of future efforts in controlling this pest:
- Biology of SWD at lower temperatures: the available data regarding biological parameters of SWD at low temperatures are limited and inconsistent. Higher accuracy in estimating temperature-dependent parameters will require more replicated studies at its lower thermal limits, ideally using insects that have experienced regionally relevant pre-winter environmental conditions.
- Reproductive diapauses: an accurate population dynamics model of SWD requires a better understanding of factors that regulate its reproductive diapause. While previous data suggest that 10°C may be a critical threshold for the biology of adults at low temperatures, recent observations in Oregon suggest the possibility of an alternative morphological variant associated with cooler temperatures and shorter photoperiod. A critical area for future research concerns whether or not this morphological change is indicative of reproductive diapause and, if so, what critical levels of temperature and photoperiod are needed to initiate its formation and influence its mortality rates.
- Host plant effects: given the high degree of polyphagy shown by SWD, a challenge facing researchers concerns the inclusion of plant phenology in population dynamics models. An effort will require a much better understanding of the relative utilization of local flora by SWD, as well as its relative seasonal abundance; both of which are likely to vary considerably across geographic region.
Source: Mark K. Asplen et al., 'Invasion biology of spotted wing Drosophila (Drosophila suzukii): a global perspective and future priorities', September 2015, Journal of Pest Science, Vol. 88, pages 469-494.
Contacts:
Mark K. Asplen
Natural Sciences Department, Metropolitan State University
700 East 7th Street, Saint Paul
MN 55106, USA
Email: mark.asplen@metrostate.edu