Relationships between Ostrinia nubilalis (Lepidoptera: Crambidae) feeding activity, crop technique and mycotoxin contamination of corn kernel in northwestern Italy

The relationships between the feeding activity of Ostrinia nubilalis (Hubner), crop technique (i.e., planting date, nitrogen fertilization, irrigation, and use of deltamethrin), and mycotoxin contamination of kernels were studied in Italian corn crop systems. Field sampling was conducted to determine the incidence of first- and second-generation larvae for each crop technique. At harvest, kernel contamination by fumonisins and zearalenon was measured and related to the number and position of tunnels on corn ears. The number of corn plants injured from second-generation larvae was partially reduced by using deltamethrin (-35%) and by bringing forward planting (-12%), whereas differences in nitrogen and water supply had little effect. The abundance of the first generation was, on average, low. The amount of fumonisin was generally one scale point higher in injured ears, and was positively related to ear tunnelling: tunnels in the apex seem to increase the amount of contamination. No links were detected between O. nubilalis presence and zearalenon contamination.