Transcript /abhps/downloads/20893.ppt

Monitoring for Variant Corn
Rootworm
Variant Rootworm
• Western corn rootworm variant lays eggs in
soybean crop (unlike traditional beetle that
lays eggs in corn crop)
• Following year, beetle hatches into corn crop
and feeds on root system, forcing need to
utilize some sort of protection on the corn
roots (Bt rootworm, seed treatment or
granular insecticide)
Sticky Trap Program
• Placing of yellow sticky traps into soybean
field to monitor corn rootworm beetle
populations allows producer to determine
need for rootworm protection in following
years’ corn crop
Sticky Trap Program for 2009
• 12 traps per field although (some fields used 4
traps)
• Placed in field mid July
• Monitored and changed weekly (for 4 weeks)
• Threshold is 5 beetles per trap per week
• None of the fields approached threshold
Cooperators
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Earl Boone, Payson
Mark Ebbing, Mt. Sterling
Bret Lipcaman, Milton
Keith Miller, Golden
Doug Sill, Mendon
Mike Vose, Orr Center/ Perry
Cooperators
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Mark Buss, Augusta and Carthage
Rex Johnson, LaHarpe
Craig Lant, Good Hope
JD Lantz, Industry
Scouting for Beetles in C-C
Rotations
• You can scout for beetles in the summer to
determine the need for rootworm control the
following year (not for variant)
• Scout for beetles from July thru August
• Count # beetles in 50 plants scattered
throughout field
• If, in any week, count exceeds .7 beetles per
plant for C-C, or .5 beetles per plant for C-SB
rotation, consider treatment to control
Corn Rootworm Beetle
• Over the past few years, there have been
fewer corn rootworm beetles found in rotated
and continuous corn fields
• This includes the variant and the traditional
beetle
• Thought is that saturated soils plus the
increased use of Bt rootworm, reduce
populations of larvae