Studies were conducted in 1990 and 1991 to investigate two kinds of soil insects that attack field corn in Virginia. Corn rootworms, the most important of which is the western corn rootworm (WCR), feed on corn roots and have been sampled effectively using yellow sticky traps. The spatial distribution of weekly counts of WCR on yellow sticky traps was investigated over three consecutive weeks in July of each year using Pherocon A.M. traps. The traps were cut in half, placed in a seven by seven grid, and separated by an average distance of 18.3 m. Data were collected in a total of 24 corn fields. Dispersion indices showed that the trap counts of WCR were aggregated. Further analysis using geostatistics revealed that the trap counts were nonrandomly distributed at least half the time at all population densities; however, the presence and type of spatial pattern was density-independent.

Pests of germinating corn seeds comprise a guild of insects including seedcorn maggots, wireworms, and white grubs. No one method has yet been developed to sample all of the insects in the guild. A new method, the baited wire trap (BWT), was evaluated in 47 fields in 1990 and 1991. No significant differences were found between the proportion of seeds damaged by pests of germinating seeds in the BWT and seeds planted by hand at conventional plant spacings. The proportion of damaged seeds in the BWT was significantly less than that in the commercially-planted fields; however, the proportion of damaged seeds in the BWT was significantly greater than the stand loss in these same fields. Linear regression revealed a significant relationship between the proportion of damaged seeds in the BWT and simulated plantings, and the conventionally planted fields. Because of low coefficients of determination (R²), the BWT could not be used to accurately predict damage by the germinating seed pest guild. However, the BWT detected damage by all three members of the pest guild and was found to be significantly faster to use than the bait station method.