DYNAMIC MANIFESTATIONS OF DIABROTICA VIRGIFERA VIRGIFERE LE CONTE IN THE CONTEXT OF THE EXCLUSION OF NEONICOTINOID TREATMENTS IN MAIZE CULTIVATION

Rezumat

The suspension of neonicotinoid-based seed treatments in 2025 in Romania has renewed concern regarding the population resurgence of the western corn rootworm (Diabrotica virgifera virgifera LeConte), one of the most destructive pests of maize. This study, conducted at the Agricultural Research and Development Station (ARDS) Livada, evaluates the short-term consequences of eliminating neonicotinoid insecticides on maize root damage, adult density, and lodging incidence. Data from prior experiments (2011) and field observations in 2025 were analyzed to assess pest dynamics under varying climatic and agronomic conditions. Results showed that treatments with neonicotinoids such as clothianidin and imidacloprid (e.g., Poncho 600 FS, Nuprid AL 600 FS) significantly reduced larval populations (up to −34 %) and minimized plant lodging (<1 %). In contrast, the 2025 observations revealed renewed plant lodging (up to 3–4 %) and increased signs of root damage, likely associated with mild winter temperatures and the absence of chemical seed protection. Although differences among green manure types and fertilization treatments were statistically insignificant, these factors showed potential for integration into ecological control strategies. The findings emphasize the need for integrated pest management (IPM) approaches that combine crop rotation, soil amendment, biological control, and resistant hybrids to mitigate the expected resurgence of D. v. virgifera populations following the withdrawal of neonicotinoids.