Harnessing the potential of Citrus natsudaidai: An attractant for Melanotus senilis larvae

Click beetle larvae have been observed to cause crop damage in various regions worldwide; however, accurate prediction of plant damage is hindered by their subterranean life cycle and the associated challenges in sampling. Melanotus senilis, a beetle belonging to the subfamily Elaterinae (tribe Melanotini) within the family Elateridae, is a destructive agricultural pest that harms maize, hops, and ginger. Our study presents novel evidence indicating the attraction of M. senilis larvae to Citrus natsudaidai (Japanese name “Natsumikan” or “Natsudaidai”). Through a field experiment involving different citrus fruits, namely natsumikan, oranges, and grapefruits, we found that C. natsudaidai attracted the highest number of M. senilis larvae. Furthermore, in a separate experiment in which C. natsudaidai and potatoes were placed in the field, C. natsudaidai significantly outperformed potatoes in attracting M. senilis larvae. These findings suggest that C. natsudaidai fruit placed on the soil surface attracts M. senilis larvae. C. natsudaidai fruits used in this study were sourced from those that remained unharvested until August. Therefore, it is possible that the C. natsudaidai fruits used for comparison were more mature than the citrus fruits used in this study. It is possible that the ripening of C. natsudaidai may have led to changes in CO₂ and ethylene emissions, potentially attracting a greater number of M. senilis larvae. Further research is required to explore these aspects in detail.