Field Crop 2024, Vol.7, No.3, 182-190 http://cropscipublisher.com/index.php/fc 185 nematodes used (Modic et al., 2020). Historical data also indicate that continuous maize cultivation and extensive use of insecticides contribute to the evolution of resistance in WCR populations, further complicating control efforts (Meinke et al., 2021). Figure 2 Diabrotica v. virgifera males caught on PAL pheromone traps 1 km away from sites 1 and 2 in 2016-2018 (Adopted from Modic et al., 2020) Image caption: The chart shows the variation over time in the number of male western corn rootworms (Diabrotica v. virgifera) captured using pheromone traps at Bucecovci (Site 1) and Smartno (Site 2). The horizontal axis represents time, from June 2016 to November 2018, and the vertical axis represents the number of male rootworms captured. From the chart, it is evident that the number of western corn rootworms captured at both locations exhibits significant seasonal fluctuations, peaking each summer (July to September). The overall trends in the number of rootworms captured at Bucecovci and Smartno are similar over the three years, but there are some differences between specific years and months. For instance, the peak capture in Bucecovci was significantly higher than in Smartno in 2016 and 2017, whereas the data in 2018 show the opposite.(Adopted from Modic et al., 2020) 4.3 Comparison of different insecticides Comparative studies have shown varying levels of effectiveness among different soil insecticides. In Nebraska, tefluthrin and bifenthrin were effective against susceptible WCR populations but less so against resistant ones. The combination of cyfluthrin and tebupirimphos also failed in highly resistant populations (Souza et al., 2019). In contrast, a study in Italy found that seed-applied clothianidin and tefluthrin applied at sowing significantly reduced WCR larval density and increased grain yield, highlighting their effectiveness in different settings (Ferracini et al., 2021). Additionally, the use of entomopathogenic nematodes was found to be as effective as tefluthrin in controlling WCR larvae, offering a sustainable biological control option (Modic et al., 2020). In summary, while soil insecticides can be effective in controlling WCR, their success is highly dependent on the resistance levels of the WCR populations and environmental factors. Comparative studies suggest that integrated pest management strategies, including the use of biological controls and crop rotation, may enhance the long-term efficacy of WCR management programs. 5 Impact on Maize Yield 5.1 Yield improvement statistics The application of soil insecticides has shown significant improvements in maize yield by effectively controlling the Western Corn Rootworm (WCR). For instance, seed-applied clothianidin and tefluthrin at sowing resulted in a maximum grain yield increase of 18% and 19%, respectively, compared to untreated controls (Ferracini et al.,
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