Life history of Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) in Nebraska

The Chrysomelid beetle Colaspis crinicornis Schaeffer has been observed more commonly in crops in eastern Nebraska in recent years. Currently, little information is available on the biology and pest potential of C. crinicornis. Therefore, a comprehensive study was initiated to examine the natural history and pest potential of C. crinicornis. This presentation contains information on the biology and life history of C. crinicornis, specifically population dynamics in corn, Zea mays L., and potential impacts of crop rotation. Single plant emergence cages were used in 2010 and 2011 to monitor emergence of adult C. crinicornis in continuous cornfields and first-year cornfields planted with soybean, Glycine max (L.) Merr., in the previous year in southeastern Nebraska. Adults were captured from June through August with peak emergence in July. Two of the three continuous cornfields sampled produced significantly higher emergence of C. crinicornis than any of the first-year cornfields monitored. The highest total seasonal emergence density was estimated to be 546,807 beetles per hectare in 2010 and 484,375 beetles per hectare in 2011. In five of the seven fields sampled, C. crinicornis was the most prevalent insect species captured in emergence cages. Field collected beetles were reared in a laboratory to obtain biological information. It is hypothesized that C. crinicornis is univoltine and overwinters as medium to almost full-size larvae in the soil in Nebraska and that larvae can develop on corn and soybean. Life history data presented in this presentation provide the baseline needed to investigate the pest potential of C. crinicornis.