Effect of simulated Helicoverpa zea damage in soybean

In order to evaluate damage and compensation levels of newer indeterminate soybean varieties to corn earworm damage, a simulated experiment was performed.  A maturity group four indeterminate variety was planted at two locations in Mississippi and received 0, 50, or 100% pod removal at four growth stages: R2, R3, R4, and R5.   It was found that simulated corn earworm damage caused significant maturity delays from the untreated control expressed as percentage of dropped leaves 137 DAP as early as R3 at 100% removal and all removal levels of the R4 and R5 treatments.  We also observed a significat maturity delay expressed as a percentage of green stems present per plot from the untreated control for both removal levels of the R5 treatment.  Significant yield loss was observed for each level of removal beyond the untreated control.  Some growth stages and removal levels appeared to compensate for fruit loss through increased pod load and increased seed count, however it wasn't always reflected in the yield.  This indicates that seed size and seed weight were likely more important factors in yield contribution.