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Earworm remains low but some ECB increase

Posted: July 2, 2013

As of July 2, 2013, corn earworm counts are low. But European corn borer counts rose in 6 counties: Bradford, Montgomery, Centre, Lackawanna, Luzern, and Montour counties have counts above threshold for corn borer. Wide spray intervals should be sufficient, or no spray in some areas.

Here is a summary of data from the sweet corn trapping network, as of July 2, 2012:

Corn earworm moth counts are low.  Most sites are below thresholds. Sites in Lancaster, Mifflin, and Washington Co. suggest a 5-6 day schedule, and one site in Lancaster had a noticeable increase.  Rainy nights may reduced the sensitivity of the traps, such that male moths would be less likely to fly to a sex pheromone lure.  However, the low numbers are coming from throughout the mid-Atlantic.  Wide-spray intervals, or no-spray, should be sufficient for earworm control at this time.

However, European corn borer counts increased in some areas.  Six counties are showing increases.  Strongest increases occurred in Bradford and Montgomery counties.  The Bradford site data may reflect the need to divide by the number of nights trapping.  Bradford and Montgomery sites suggest a 5 day spray schedule.  Additional sites in Centre, Lackawanna, Luzern, and Montour counties suggest 6 day spray schedules.  Bt-sweet corn will not be damaged by ECB. 

Fall armyworm has been confirmed in Centre Co., and high counts continue to be reported from Lycoming and Schuylkill counties.  At this time of year, high counts often due to nontarget captures of Leucania phragmatidicola  (a moth that does not have a common name).  See:http://ento.psu.edu/extension/factsheets/armyworm-pheromone-captures

In summary, corn earworm counts are low.  But European corn borer counts rose in 6 counties: Bradford, Montgomery, Centre, Lackawanna, Luzern, and Montour counties have counts above threshold for corn borer.  Wide spray intervals should be sufficient, or no spray in some areas.

See www.pestwatch.psu.edu for maps and detailed reports.