After several years of low corn rootworm pressure (CRW), populations of this insect may be on the rise in Iowa. Data collected in October by the Iowa Soybean Association On-Farm Network reports an uptick in the number of both the Northern and Western corn rootworm adult beetles in corn fields across the state. The most severe infestations scouted were also in the driest areas so a high rate of larval survival was likely a factor.

The charts below show the corn rootworm population per trap per day:

 

The 3 species to look out for are Western, Northern, and Southern CRW beetles. Some things to keep in mind about this insect include:

• Eggs are laid in mid-to-late summer and overwinter
• Eggs hatch from mid-May to early June
• Larvae start feeding within 3-4 hours of hatching

       Larvae stage                              Western                  Northern                 Southern

With an increased number of beetles spotted in October 2017, what does this mean for the 2018 season? While factors like temperature and weather can affect the larval survival rate, it is still important to recognize the rising population and prepare accordingly. We suggest an insecticide like Force® Evo or Force® 3G that helps protect developing corn root systems against insects. For more information, please contact your local Syngenta Sales Representative.

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