MONITORING OF CORN BORER ADULTS IN THE CENTRAL-EASTERN ITALY: SPECIES COMPOSITION, FLIGHT DYNAMICS AND FIELD TESTING OF THE ELECTRONIC TRAPS

Maize (Zea mays L.) is a globally significant staple crop and among the threats to its production there are three corn borer species: Ostrinia nubilalis (Hübner, 1796) (Lepidoptera: Crambidae), Sesamia nonagrioides (Lefèbvre, 1827), and Sesamia cretica (Lederer, 1857) (Lepidoptera: Noctuidae). Larvae of these species can cause relevant direct and indirect yield losses, limiting the marketable product. Adult monitoring is fundamental for the management of these species, as it allows to acquire information on their presence, their flight dynamics and, consequently, the best timing for the implementation of different control actions. Adult monitoring is usually carried out by using pheromone-baited traps, where the type of trap and the effectiveness of the pheromone are crucial for a reliable monitoring activity. These aspects emerged as particularly relevant for O. nubilalis, where pheromone polymorphism occurs, and for which the monitoring effectiveness highly depends on the correspondence between the pheromone-strain used and those present in the monitored area. To date, the possible use of electronic traps in monitoring are becoming of great interest also for corn borers. Given the importance of the monitoring and the challenging situation of the central-eastern Italy, where the three species can occur in the same area, the following research activities were carried out: i) monitoring the composition, the relative abundance and the flight dynamics of the corn borer species; ii) compare the new pheromone-baited electronic traps with the traditional cone traps for O. nubilalis. Activities were conducted in two corn fields of the Azienda didattico-sperimentale “Pasquale Rosati” of the Polytechnic University of Marche – Agugliano (AN), in 2024. In the first field, adult monitoring of O. nubilalis was performed using twelve Coretraps® (three traps per each strain and the hybrid plus three traps with phenylacetaldehyde - ISAGRO®) and three SCM Cone-net (TRAPVIEW®) baited with the E strain-pheromone. In the second field, three green funnel traps baited with pheromone (Novapher®) were installed for each Sesamia species. The results of the surveys highlighted the co-occurrence of all three corn borer species and the presence of the two strains and the hybrid of O. nubilalis in the same area. Captures of O. nubilalis followed a similar pattern among the strains and the hybrid, peaking in mid-to-late August, with the E strain being the most abundant (more than 50% of the total amount of captured individuals). Although the number of total captures were fewer in the electronic traps compared to the traditional ones baited with the same strain, they returned a comparable flight dynamics and abundances. S. cretica was more prevalent compared to S. nonagrioides (around 75% of the total captured individuals) and the highest captures were recorded between mid-July and mid-September. This study highlights the importance of monitoring corn borers to adapt management strategies based on species composition and relative abundances.