Western Bean Cutworm Injury Discovered in 2010, What does it mean for 2011?

by Greg LaBarge, Fulton County

The first detections of feeding injury from Western Bean Cutworm in the NW corner of Ohio were discovered during the 2010 growing season. This was the first year all growth stages of this insect: adult moth, eggs and larvae stages were observed during the growing season with associated ear feeding on corn. The question is what do we expect for 2011 from this new insect?

To start to answer the question of what we could expect from WBC in 2011 we can look to the west. Lake County Indiana had adult moth caught in 2006. The first feeding damage happened in fields during the 2007 growing year and economic or widespread injury in 2009. This type of spread has been repeated as the insect has moved east. Based on this experience we might find economic damage in 2011 and very likely by 2012.

The map below was assembled by Tracey Baute, Ontario Ministry of Agriculture, Food and Rural Affairs and represents 2010 observations in the Great Lakes Region. Yellow counties are where damage was seen and the gray/purple were sites with economic injury or heavy feeding.

Management of WBCW can be accomplished in a couple of ways. Corn hybrids with Herculex I (Cry1F) and Herculex Xtra or SmartStax because of the inclusion of Herculex I or Optimum AcreMax 1 and  Optimum Intrasect (because of Herculex I) or Viptera 3110 and 3111 with new VIP protein have resistance that will limit development. For hybrids without genetic resistance we can use scouting with a threshold is 5%-8% larvae and/or larva feeding after inspection of 20 plants in 5 areas. Numerous insecticides can be used.

Adult moth trapping with pheromone traps can be used as a reference to know when moth flights are occurring and what corn fields are in the right growth stage preferred for egg laying (late whorl V8-V10). This is typically mid July through early August.

2010 observations of larvae feeding were found in 2 fields in Fulton County. Fields in which feeding occurred were later planted, near Memorial Day Weekend. Eggs of Western Bean Cutworm were confirmed on July 13th in a field near Wauseon. A second field was identified later in the month. The feeding seen in 2010 was not economic or widespread. At least one other field in Defiance County was also observed with feeding injury. A good reference on WBCW scouting is a video from Purdue University that ccan be found at: http://www.youtube.com/watch?v=BFXRELD6T9E

An Ohio produced fact sheet on Western Bean Cutworm can be found at http://ohioline.osu.edu/ent-fact/pdf/0040.pdf

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