Molecular Soil Biology 2024, Vol.15, No.3, 140-150 http://bioscipublisher.com/index.php/msb 143 4.2 Field studies and experimental data on insecticide performance Field studies have consistently shown that soil insecticides can effectively control WCR populations and mitigate root damage. For instance, a two-year study in Northern Italy evaluated different chemical control strategies and found that both seed-applied and in-furrow soil insecticides significantly reduced WCR larval density and increased grain yield by up to 19% (Ferracini et al., 2021). In another study, the combined application of entomopathogenic nematodes and chemical insecticides in Austria resulted in the lowest number of WCR adults and minimal root damage, although grain yield was not significantly affected compared to untreated controls (Rauch et al., 2017). Additionally, a three-year field experiment in Slovenia demonstrated that soil-applied tefluthrin and entomopathogenic nematodes were equally effective in reducing WCR beetle emergence and increasing maize plant weights (Figure 2) (Furlan et al., 2022). Figure 2 Map showing the regions in Italy and Croatia surveyed for WCR damage between 2003 and 2017 (Adapted from Furlan et al., 2022) Image capton: The locations of Venice and Zagreb are indicated by black circles. Orange coloring indicates areas surveyed for risk factors in Italy and Croatia. The numbers associated with surveyed areas in Croatia indicate the numbers of fields that were monitored. In Veneto, Italy, monitored fields were distributed throughout the entire maize cultivation area. Red symbols indicate the areas in Italy where farmers applied structural crop rotation and the blue symbol indicates the area where farmers applied flexible crop rotation. In Croatia, no comparisons of crop rotation regimes were conducted (Adapted from Furlan et al., 2022) Furlan et al. (2022) investigated the impact of different crop rotation strategies on the management of Western Corn Rootworm (WCR) damage across regions in Italy and Croatia. Their study highlighted significant regional differences in agricultural practices, with structured crop rotation being more prevalent in certain areas of Italy, particularly in regions such as Veneto. This structured approach was contrasted with the flexible rotation strategies employed in other areas, which allowed for adjustments based on specific conditions and crop requirements. The research underscored the importance of tailored agronomic strategies in mitigating WCR damage and suggested that the lack of comparison between crop rotation regimes in Croatia may have implications for the effectiveness of pest management practices in that region. The study's findings emphasize the need for ongoing risk assessment and adaptation of crop management practices to local conditions to optimize pest control efforts. 4.3 Factors influencing the efficacy of soil insecticides The efficacy of soil insecticides in controlling WCR populations can be influenced by several factors, including soil type, application rate, and environmental conditions. For example, the effectiveness of soil insecticides was found to be consistent across different planting times and soil types in Northern Italy, suggesting that these factors did not significantly impact insecticide performance (Jaffuel et al., 2019). However, in Nebraska, the presence of pyrethroid-resistant WCR populations significantly reduced the efficacy of soil-applied bifenthrin and tefluthrin,
RkJQdWJsaXNoZXIy MjQ4ODYzMg==