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Current Distribution of Western Bean Cutworm in the Great Lakes Region

I recently worked with a few of my counterparts in the US and here, including Chris DiFonzo (MSU), Ron Hammond and Andy Michel (OSU), John Tooker (PSU), Keith Waldron (Cornell U) and Chris Gillard (UGRC) to combine our data and put together the latest map of the spread of western bean cutworm in the Great Lakes Region.

2009 was obviously a very active year for western bean cutworm, as predicted. This pest continues to spread further north and east into the Great Lakes Region. A total of 252 traps went up in our region this year, with the majority catching moths (Figure 1). This year, trapping was expanded into New York, Pennsylvania, eastern Ontario and Southern Quebec. Trap catches confirmed that WBC has now expanded as far north and east as southern Quebec, eastern Ontario, New York and eastern counties of Pennsylvania. An astonishing total of 28289 moths were captured in Michigan while Ohio, Ontario, Southern Quebec, Pennsylvania and New York captured 566, 1637, 8, 93 and 11, respectively. Four dry bean producing counties in central Michigan were advised to spray based on trap count numbers and signs of pod feeding. Several counties in both Michigan and Ontario have reported feeding damage and larval activity (yellow), though no damage has been reported in dry beans in Ontario to date. Michigan reports that some counties (purple) experienced economic damage in both corn and dry beans.

Figure 1. 2009 Western Bean cutworm trap results for the Great Lakes Region. 252 traps were monitored in total. Numbers indicate total moths captured in each county. Shaded counties reported having WBC feeding damage (as of October 28, 2009). Purple counties (9 western counties of Michigan) experienced economic damage (spraying or yield loss).

What does this mean for 2010?

WBC is here to stay and will continue to spread north and east. There is a good chance it will overwinter in some counties in Ontario this winter and is certainly doing so in Michigan. I can't say for sure that no economic damage will occur next year in Ontario but I suspect that it will still be limited to a few hot spot areas of the province, similar to what Michigan dealt with in 2008. Blyth area in particular is a concern, given the large amount of dry bean acreage there and the number of moths captured two years in a row. Through trap monitoring and scouting we will do our best to stay on top of the situation. I will work at providing you more information this winter through meetings, presentations, media articles and my blog to prepare you for next year. Most will likely still only see the same sort of damage levels we are seeing this fall but some may need to take action and spray next year. Only trap counts and scouting will help determine if action is necessary.

Does this mean that everyone needs to start planting Herculex corn to control this pest next year? Not likely. Again, we haven't reached economic levels in Ontario to justify the additional costs of using Herculex to specifically control this pest. Michigan is about two years ahead of us with dealing with infestations of WBC and just experienced economic damage for the first time this year and that has been limited to four counties so far. Also remember Herculex does not give 100 percent control so some feeding may still occur. As well, the refuge planted will still be vulnerable so scouting is still going to be necessary. Spray thresholds in corn are much more reliable than the ones used in dry beans. Research is underway to develop new dry bean thresholds for the Great Lakes Region and work is ongoing to obtain registration of foliar insecticides for both the dry bean and corn crops in Canada.

Acknowledgements

Funding for the Ontario WBC Trap Network was provided in part by the Ontario Corn Producers' Association, OMAFRA through the Agricultural Adaptation Council's Ontario Research Development (ORD) Program and the Ontario White Bean Producers. I'd like to thank my colleagues, Gilles Quesnel, OMAFRA and Michele Roy, MAPAQ for helping set up the trap network in eastern Ontario and southern Quebec. We would also like to thank all co-operators including growers, ag. industry reps, retailers and extension staff who monitored traps. A special thanks to the technicians and summer students involved including Katrina Schaafsma, Robyn DeBrouwer, Brianna Vyn, Steve Willis, Mike Jewett, and Chelsea Smith.