Western Bean Cutworm

Western Bean Cutworm trap numbers are down across Southwestern Ontario for the second week in a row. Peak flight has occurred and fields should have been scouted by now for any cutworm egg masses to control.

This will be the last week for publication of the trap counts from Sylvite. Thank you all for your participation and keeping track of our WBC trapping network throughout the summer!

Western Bean Cutworm trap counts are dropping now across all regions in Ontario, as peak flight has passed and moth flights decline.

In the southern regions, moth flight is rapidly declining, with counts ranging from 0-48. There is still potential for egg laying as some moths are still active, so it is important to continue to scout corn and edible bean fields.

In the eastern and northern regions, moth counts are declining, although there are still areas with some higher pressure, especially in the Port Albert area, Mitchell area, and eastward toward Cambridge. In these areas, there are still traps catching upwards of 100-200 moths per trap, and so moths are still highly likely to be laying eggs in fields. Trap counts throughout the region range from 0-283.

The main focus for scouting now will be in edible bean fields, as moths will be looking to lay eggs in fields with fresh, growing bean pods. It is more difficult to scout for Western Bean Cutworm larvae in edible beans, and so it is important to talk to your Sylvite representatives for thresholds on control in edible bean fields. As well, check out our blog post on Western Bean Cutworm.

Western Bean Cutworm trap counts seemed to have peaked last week in the Chatham-Kent, Elgin and majority of Huron and Perth counties, while numbers are still climbing north of Goderich & Mitchell.

In the southern region the majority of traps are showing a decrease in moth counts, apart from a few traps in the Blenheim/Ridgetown area and in the Wallaceburg/Dresden area. This indicates that last week was peak flight time and now is the time to get out to fields and scout for the egg masses. Trap counts in the region are ranging from 0 to 543 moths trapped.

In the northern and eastern regions moth counts are also decreasing for the most part. There are some hot spots around Goderich, Mitchell and Woodstock that are still showing increasing numbers though. For most areas though peak flight of the moths was last week and it is time to get out in the fields and look for those egg masses. Trap counts in the region are ranging from 0 to 878 moths trapped.

For instructions on scouting for the egg masses, thresholds for corn and dry beans and control options, please visit our blog post on Western Bean Cutworm.

Western Bean Cutworm trap counts are still increasing across the majority of the province.

In the Chatham-Kent area some trap locations in earlier planted areas of the county are showing a decrease in numbers. The rest of the Chatham-Kent/Elgin area still shows moth counts increasing with the highest counts still being seen in the historical hot spot areas with sandy soils. This indicates that peak flight is likely occurring this week for the majority of the traps in the south. Trap counts next week will confirm that peak flight has occurred if the numbers decrease for the remainder of traps in the southern region of our network. Moth counts for traps in the southern region range from 4-590.

All traps in the northern and eastern regions are still showing increasing trap numbers, which means that peak flight of the moths has yet to occur, but likely will in the following week. Moth counts for traps in these regions range from 0-350.

Peak flight is when the maximum amount of Western Bean Cutworm moths are flying through the fields and laying eggs. These egg masses are what to look for when trying to determine whether to spray an insecticide for control or not to. When peak flight happens it is time to get out into the fields and start scouting for the egg masses. Spray is warranted if 5% of plants have egg masses on them. Look at the upper 3-4 leaves of the corn plant for the egg masses. The eggs are laid on the upper surface of the leaf so the most efficient way to spot them is to look for the shadow of the egg mass from the underside of the leaf.

Western Bean Cutworm numbers are increasing rapidly in the southern region of the province with numbers just starting to climb North and East of London. Traps in the Chatham-Kent/Elgin area are showing trap counts of 0-182 with many traps near or above 100 moths counted. Traps North of London look to be about a week behind traps in the southern region, and are showing trap counts of 0-72.

The higher numbers are typically being seen on sandier soils and more advanced corn fields that are tasseling and pollinating. Fields that haven’t yet begun to tassel or are on heavier clay soils are still seeing lower numbers of moths in the traps. Based on trap counts from previous years peak flight could be observed next week in the southern region and a couple weeks from now in the northern region.

Western Bean Cutworm trap counts are still increasing across the majority of the province.

In the Chatham-Kent area some trap locations in earlier planted areas of the county are showing a decrease in numbers. The rest of the Chatham-Kent/Elgin area still shows moth counts increasing with the highest counts still being seen in the historical hot spot areas with sandy soils. This indicates that peak flight is likely occurring this week for the majority of the traps in the south. Trap counts next week will confirm that peak flight has occurred if the numbers decrease for the remainder of traps in the southern region of our network. Moth counts for traps in the southern region range from 4-590.

All traps in the northern and eastern regions are still showing increasing trap numbers, which means that peak flight of the moths has yet to occur, but likely will in the following week. Moth counts for traps in these regions range from 0-350.

Peak flight is when the maximum amount of Western Bean Cutworm moths are flying through the fields and laying eggs. These egg masses are what to look for when trying to determine whether to spray an insecticide for control or not to. When peak flight happens it is time to get out into the fields and start scouting for the egg masses. Spray is warranted if 5% of plants have egg masses on them. Look at the upper 3-4 leaves of the corn plant for the egg masses. The eggs are laid on the upper surface of the leaf so the most efficient way to spot them is to look for the shadow of the egg mass from the underside of the leaf.