How Will The Western Bean Cutworm Over Winter?

2010 brought a new observed level of the Western Bean Cutworm to NW Ohio corn production. Defiance and Fulton Counties each caught over 400 WBC moths in their respective four traps during summer monitoring and each county located at lease one field with WBC larves in the corn ear. However, 2010 corn fields did not reach economic thresholds that would warrant rescue treatments.

Since 2006, WBC has increased in numbers here in Ohio to the point where NW Ohio might expect the insect to complete its life cycle by over wintering rather than only moth flight migrating to Ohio during the growing season.

How do they survive the winter? Large larvae (6th or 7th instar) emerge from the ear and fall to the ground, burrow 3 to 6 inches into the soil, and construct an earthen overwintering cell (Figure). They spend the winter inside this cell in a pre-pupal stage. Larvae pupate in late May followed by adults crawling up through the soil with emergence starting in early July.

OSU Ext Factsheeet: http://ohioline.osu.edu/ent-fact/pdf/0040.pdf

reference: http://tinyurl.com/37asbqe (Univ. of Nebraska, Lincoln)

Dry Soils Impacting: Tillage and Soil Sampling

Moderate rainfall yesterday and overnight gives promise that area farmers might find relief to hard, dry soils. The Defiance Memorial Airport NOAA weather station reports 0.75" of rainfall during November 16 & 17, 2010. Farmers are reporting machinery repairs every 3-4 days or every 50-60 acres from excessive wear and tear on tillage tools.

An area farmer shared that "Replacement bolts, shanks, etc quickly add up to $1,200 each week. A small bag of high grade bolts seem to cost more this fall and they don't last long. The deep shanks bend and bow to follow the cracks in the soil rather than busting through."

Private consultants and farmers collecting soil cores are also feeling resistance. Power augers and hand probes are bending and worn and need maintenance and replacement more regularly.

Agronomists and farmers should anticipate that soil test results reported from very dry soil samples collected may have drought induced lower pH and potassium levels this fall. OSU and Purdue Ag Answers addressed this effect in an October 2010 article: http://www.agriculture.purdue.edu/aganswers/story.asp?storyID=6109