A factorial experiment was conducted in the greenhouse to measure the effects of aboveground herbivory by European corn borer on the activity of Meloidogyne incognita in potted corn plants. The experimental design consisted of three levels of herbivory (0, 1, and 3, third instar European corn borers per plant), at each of the three plant growth stages: 6-, 8-, and 10-leaf stages. Nematode inoculation consisted of applying 6,000 M. incognita eggs and juveniles near the base of each plant after 72 hours of European corn borer infestation.

Corn plants were harvested two weeks after nematode inoculation. On each plant, stalk tunnel length from European corn borer and number of root penetration events from M. incognita juveniles were recorded. The levels of herbivory had a significant effect on the number of M. incognita juveniles penetrating in the root tissues (P=0.0038). The mean penetration numbers of 20.0 and 12.5 recorded for plants with 1 and 3 larval infestation levels per plant, respectively, were significantly less than the mean penetration number of 31.8 for plants with no infestation. Stalk tunnel lengths and root penetration numbers were significantly inversely correlated (P=0.05, r=-0.4438). For further understanding of the effects of aboveground herbivory on belowground herbivory in corn, another set of experiments is currently under way to measure the effect of European corn borer stalk tunneling on M. incognita egg production.