Monitoring for strawberry aphids in Ontario

Strawberry aphids are a concern for growers across the province because they are the most efficient vector for strawberry viruses. It is important to scout fields consistently to monitor aphid populations as well as to monitor for when winged aphids begin to appear. This is the most critical stage for control because the winged aphids will be able to fly to different fields and farms, and spread the virus.

To monitor for strawberry aphids take a direct sampling of the newest growth, leaves that are folded or recently unfolded (figure 1). The strawberry aphids can usually be found on the underside of the leaves (figure 2). The majority of the aphids we are finding have been strawberry aphids; however to guarantee correct identification they can be distinguished from other aphids by their knobbed hairs, which can be seen under a microscope (figure 3). Check at least 50 leaves per block.

My summer project is focused on learning more about strawberry aphids in Ontario. We are currently monitoring for aphids at 15 farms weekly in different regions in the province. We monitor from day neutrals, two or three year-old plantings, as well as new 2014 plantings. We have found a big difference between fields, which seems to be related to plant vigour and insecticide use. We are also trying a couple of other methods of monitoring targeted at winged aphids. We have set up yellow sticky traps and yellow bowl traps to try to catch the winged aphids as they fly from field to field (figures 4 & 5). So far, it seems easier to check for winged aphids by looking directly on the leaves (figure 6).