Seasonal dynamics and abundance of brown marmorated stink bug Halyomorpha halys (Stal) on four trap crops

The main purpose of the study was to examine the potential of crops, such as soybeans (Glycine max), sunflowers (Helianthus annuus), alfalfa (Medicago sativa), and sorghum (Sorghum bicolor), as trap crops for Halyomorpha halys. We monitored the abundance and seasonal dynamics of H. halys (egg clusters, larvae, and adults) on a selected number of various crops at 10-day intervals. The experiment was performed in two different regions of Slovenia (western and central) and in two different years (2021, 2022). The results varied depending on the location and the year. In the first experiment, data from the entire year showed that sorghum was the most attractive for H. halys adults (1.56 +/- 0.12), followed by sunflowers (0.61 +/- 0.05), soybeans (0.37 +/- 0.03) and alfalfa (0.41 +/- 0.21). In the second experiment, the abundance numbers of the pest were significantly lower compared to those of the first experiment [sorghum and soybeans (0.003 3 +/- 0.002), sunflowers (0.000 3 +/- 0.000 3)]. In both cases, the abundance numbers increased when all the crops entered the fruit development stage (BBCH 70+). Overall, the lower density of the H. halys population and the experimental design could also be some of the factors for such a low incidence of stink bugs in the central region of the country. More research will be needed to further develop effective control methods for this invasive pest.