On the conference call with my US counterparts yesterday, it was mentioned that fields in NE Iowa are starting to see soybean aphids colonize soybeans there.
This is a good indication that once our soys are emerging we should be scouting fields once a week to monitor for aphids. Particularly those4 fields that are first to emerge in the area.
The first report of spraying for armyworm in sweet corn in Essex County came in today. We are not sure how heavy of infestation to expect in other fields but wheat and newly emerging corn fields should be scouted in Essex, Chatham-Kent, Lambton, Elgin and Middlesex counties asap. Armyworm reports from Essex tend to give us a few days heads-up to catch any infestations in the neighbouring counties. But other counties in southwestern Ontario should be scouted in the next 7 days to 10 days to determine if armyworm is present there.
A CropPest Newsletter article will go out later this week with details on scouting and management strategies. You can also find information in the Agronomy Guide for Field Crops and past CropPest articles (links provided below)
http://www.omafra.gov.on.ca/english/crops/pub811/3taw.htm
http://www.omafra.gov.on.ca/english/crops/field/news/croppest/2008/05cpo08.htm
Wayne Black: 
Tracey Baute: 
Ontario Agriculture : 
Jeff Steiner: 
David Townsend: