Life Cycles of the
European Corn Borer
in South Dakota

Michael A. Catangui, Ph.D. - Associate Professor
 South Dakota State University

(Click on thumbnail for a larger image)
Figure 2. Life cycle of univoltine European corn borer in South Dakota

    The bivoltine or the 2-peaked moth flight pattern has been observed in counties along and to the south of Interstate Highway 90. The univoltine or 1-peaked moth flight pattern has been observed in counties north of Minnehaha County along Interstate Highway 29, and counties along the North Dakota border.

    Tracking of moth flights is currently ongoing.  Moth flights in some areas are still unknown.  "Transition zones" where the univoltine and bivoltine flights appear to converge can be found in some counties.  For example, the moth flight in Dell Rapids, SD do exhibit both univoltine and bivoltine components.

    Univoltine larvae can be more destructive since they do not stop feeding to transform into an inactive stage during the season.  That is, the larvae stay in the plant from June through harvest.  In the bivoltine cycle, there is a lull in feeding for about 2 weeks when the larvae transform or metamorphose into pupae then adults which will then lay eggs that will become the second brood larvae.  Univoltine larvae do not transform into pupae until the spring of the following year.