A recent summer migration of soybean aphids in Ontario has resulted in many new fields having a fair number of aphids in them now. Fields that were scouted a week or two ago and were found to have very few aphids could now be closer to threshold than you think. Scouting is advised. Scout Cruiser treated fields too as we are starting to see some of these fields also nearing threshold now.
Admittedly some people got lucky. Some of the fields that were infested earlier this year and were rising in numbers are the ones that the aphids developed wings in and left so they may have dropped in numbers and no longer need to be sprayed. But again, scouting is advised to determine which fields this migration has impacted, good or bad.
Recent soybean aphid scouting maps for Ontario can be found at: http://sba.ipmpipe.org/cgi-bin/sbr/public.cgi?host=All%20Legumes/Kudzu&pest=soybean_aphid
This weeks map will also go up on the OSG site later tomorrow (Friday Aug 7th) at: http://www.soybean.on.ca/aphids.php