Fig 1.
Location of western corn rootworm populations tested in plant-based bioassays.
The map represents the state of Iowa, USA and individual sections of the map are counties in Iowa. Symbols represent individual fields that were sampled for adult western corn rootworm and subsequently tested in bioassays. Field locations are accurate to the level of an individual county. CPF = current problem field, PPF = past problem field, RMF = rotated maize field, and CMF = continuous maize field.
Fig 2.
Survival of western corn rootworm larvae on Cry3Bb1 maize and non-Bt maize in plant-based bioassays.
Bar heights are sample means and error bars are the standard error of the mean. Uppercase letters indicate significant differences between population classes on non-Bt maize and lowercase letters indicate significant differences between population classes on Cry3Bb1 maize. Differences between Cry3Bb1 maize and non-Bt maize within a population class are indicated by either NS for a non-significant difference or Sig., which stands for a significant difference.
Table 1.
Analysis of variance for data from plant-based bioassays.
Table 2.
Proportion of third instar larvae on Cry3Bb1 maize and non-Bt maize1.
Table 3.
Larval survivorship of western corn rootworm in plant-based bioassays.
Fig 3.
Relations between diet-based and plant-based bioassays for western corn rootworm.
Horizontal lines represent 95% fiducial limits on LC50 values and vertical lines represent the standard error of mean for corrected larval survivorship on Cry3Bb1 maize. Individual points represent samples means. Lables by individual data points represent the follwing: CPF = current problem field, PPF = past problem field, RMF = rotated maize field, CMF = continuous maize field, and CTRL = control population.
Table 4.
Pobit analysis of larval mortality in diet-based bioassays.