Survival of the western and northern corn rootworms (Coleoptera: Chrysomelidae) in different tillage systems throughout the growing season of corn
1988
Gray, M.E. | Tollefson, J.J.
The influence of tillage practices on growing-season survival of western and northern corn rootworms, Diabrotica virgifera virgifera LeConte (WCR) and D. barberi Smith and Lawrence (NCR), respectively, was examined from 1983 to 1985. Absolute estimates of spring egg densities and emerging adult densities were made each year for both species across all tillage systems. Estimates of relative variation (SEM/average) were calculated for WCR and NCR egg and adult densities during each year of the experiment. Tillage practices did not significantly affect WCR or NCR survival throughout the growing season of corn. Survivorship differed significantly between WCR and NCR. Western corn rootworm survival was greater than that of NCR in each tillage practice for the duration of the study. The following quadratic equation was calculated to describe the ratio of WCR/NCR adults (y) likely to emerge based upon the spring WCR/NCR egg ratio (x): (y = 0.905 - 0.028x + 3.246 x2 [R2 = 0.91; n = 12; P less than 0.01]).
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