The species composition of rice stink bugs in Shizuoka Prefecture, Central Japan, was investigated. In the eastern region of Shizuoka Prefecture, the number of rice stink bugs and the proportion of Stenotus rubrovittatus were low. In contrast, in the western region of Shizuoka Prefecture, the number of rice stink bugs and the proportion of S. rubrovittatus were high. There was a weak positive correlation between the percentage of Lolium multiflorum that emerged around the field, and the number of S. rubrovittatus captured in the rice paddy levees and the surrounding weeds. Additionally, the proportion of Lagynotomus elongatus has increased in the western region of Shizuoka Prefecture since 2018. The effects of four insecticides (MEP [fenitrothion], ethiprole, etofenprox, and dinotefuran) on adult S. rubrovittatus individuals were investigated. The results showed that all insecticides, especially MEP and etofenprox, were effective.

Species Composition of Thrips on Chrysanthemum and Weeds weedy plots, are known to increase the population size of insect pests and the indirect damage to agricultural crops (Carrière et al. 2006, Yasuda et al. 2011. Many species of thrips infest weeds (Miyazaki & Kudo 1988), and some thrips are found at high densities on several weed species (Katayama 2006, Larentzaki et al. 2007, Smith et al. 2011. In addition, it has been suggested that weeds can act as overwintering habitats for some of the species of thrips (Katayama & Ikeda 1995, Morishita 2005, Katayama 2006). Thus, it is possible that weeds could be sources of pests that can invade chrysanthemum fields. Katayama (2006) investigated the relationship between the abundance of thrips on chrysanthemum and weeds. However, in the study, only Frankliniella occidentalis was observed, and there are no concurrent studies of multiple species of thrips. In the present study, we investigated the species composition and seasonal abundance of thrips populations on open-field chrysanthemum grown for cut flowers and the surrounding weeds throughout the year in Hamamatsu City, a major chrysanthemum production JARQ 56 (1), 49-58 (2022) https://www.jircas.go.jp