Seedcorn maggot (Delia platura) is a globally distributed agricultural pest that feeds on the germinating seeds of economically important crops, including corn and beans. The larvae cause underground damage, which can lead to stand loss. For decades, D. platura has been managed using insecticide-coated seeds, but following the ban on neonicotinoid-coated corn, soy, and wheat seeds in New York State, this practice will no longer be available. Degree day models have been used to predict the emergence of the overwintering generation of agricultural pests since the late 1900s. However, the terminology used in the literature to distinguish degree day thresholds for first emergence and peak emergence is unclear, and previous reports of a 360 degree day emergence threshold did not align with field observations. In 2023, we captured the first emergence at four sites, and in 2024, we monitored adult D. platura at 25 sites in New York State. We observed the first adult emergence between 52 and 197 accumulated degree days (98 +/- 7 degree days, mean +/- 1 SE) using a biofix of January 1st, confirming that in New York State, D. platura emergence is earlier than previously reported values. Additionally, we note adult activity during December 2023 and January 2024, suggesting that warming winters may impact our ability to predict pest emergence. We propose future models should incorporate both degree day information and other regionally specific factors known to impact pests, including farm management, soil conditions, and landscape composition, for more accurate predictions.

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.