Spotted wing drosophila (SWD) is an invasive vinegar fly that has rapidly spread across much of North America. First observed in Ontario in 2010 and now widespread in all fruit growing regions of the province, this insect has become quite familiar to most growers of conventional soft skinned fruit, such as cherries, blackberries, raspberries, blueberries and strawberries. Unfortunately, specialty berries are not immune to this pest.
SWD were isolated from goji and sea buckthorn berries beginning in 2012, but had not yet been detected in Ontario haskap. In mid-July of this year, spotted wing drosophila were detected in haskap berries left on plants after harvest. Haskap growers should be aware that their berries can be a host of SWD but likely escapes significant damage because haskap harvest is typically completed before SWD populations peak in late July. Haskap and other specialty berry growers should be looking for this pest, particularly if later harvests are planned.
Spotted wing drosophila is unlike many other fruit flies in that it is attracted to and can lay eggs in healthy ripening fruit, rather than overripe or damaged fruit. Egg-laying may result in pin-prick sized scars on the surface of the fruit, and larval feeding within the fruit can cause wrinkling and softening within a few days. Softened skin collapses and may develop mould.
Growers of specialty berries should make themselves familiar with the signs and symptoms of SWD and watch for them on their crops. For more information on biology, identification and management of spotted wing drosophila, refer to the SWD page on the OMAFRA website at http://www.omafra.gov.on.ca/english/crops/insects/drosophila.html. Note that haskap and sea buckthorn fall into crop group 13-07B for the purpose of pest control product registrations. Only products with this crop group on the label can be used on these crops. Products labelled only on specific berries (e.g. strawberries, blueberries) cannot be used on haskap or sea buckthorn. Goji berry is in the fruiting vegetables Crop Group 8-09 – only products registered on this group can be used on goji.