Think Like a Rootworm Beetle... Pollen and Soybean– (John Obermeyer and Larry Bledsoe)
- Late pollinating corn and/or weeds may attract large numbers of rootworm beetles.
- Egg laying during august may cause considerable root damage to next year's corn.
- Rapid maturity of the corn may be encouraging earlier and more beetle movement to soybean.
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Western corn rootworm beetles
feeding on weed pollen |
We continue to receive reports about various situations that have attracted tremendous numbers of western corn rootworm beetles. This includes late-planted/replanted corn and weed escapes through the
soybean canopy. Remember, the rootworm beetles are
pollen feeders, and not just corn pollen (e.g., foxtails,
ragweeds, lambsquarters, pigweeds, etc.). Numerous
beetles that converge on these “trap” crops will likely
encourage significant egg laying for next year’s corn
roots. Investigations of these areas during August will
help one make informed decisions for next year, i.e.,
rootworm insecticides.
Because of the rapid growth and maturity of this
year’s corn crop, it seems that the variant western corn
rootworm beetle is moving to soybean fields earlier than
normal. Ultimately this means that more mating and egg-laying than previous years may be occurring for a
given area of the state. This was reported in last week’s
Pest&Crop concerning west central Indiana counties
south of Interstate 70. We continue to encourage pest
managers to observe for the beetle’s presence in their
soybean fields, and not rely solely on our county sweep
survey for next year’s insect management decisions.
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Beetles demolishing silks of late-planted corn |
Soybean Aphid Update– (John Obermeyer, Larry Bledsoe, and Bob O'Neil)
No news continues to be GOOD news. Though
soybean aphid can be found in many soybean fields in
northern counties, densities remain very low. We are
aware of one soybean seed field that was treated in
Marshall County over a week ago, however the numbers
were far below the threshold of 250 aphids/plant.
Considering that much of the same is occurring
throughout the Midwest, we have very little concern
about an influx of aphids carried on weather fronts.
Soybean growth and development continues to make
excellent progress and moisture doesn’t appear to be a
limiting factor for the crop. Though we are not completely
out of the woods for this season,
the clearing is in sight.
What a contrast from
last year!
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Click for Table.
Black Light Trap Catch Report.
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