Climate change can affect major changes to the dynamics of individual insect. The increase of surface temperature would cause multivoltine species to increase the number of generations (i.e. voltinism) per year. Determining the voltinism was based on the climate data and biological parameters. The soybean bug, Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) is one of major pests of soybean and has multi host plants. To estimate the voltinism of R. pedestris, the climate data were obtained from the web site of the Korea Meterological Administration(KMA) from 1966 or 1973 to 2015 at 77 locations, respectively. We used the lower developmental threshold (15.0°C) and thermal constant (312.5DD) for R. pedestris from egg to adult emergence. Degree-days were calculated by using simple cutoff method and cumulating degree-days (CDD) were obtained by summing calculated degree-days. The voltinism of R. pedestris was calculated by dividing CDD per specific period by the thermal constant requirement of R. pedestris development from egg to adult emergence. The number of generations varied depending on the season, with the lowest in February and the highest in August at each location. At least one generation per month would be possible from July to August. The average voltinism from 1966 to 2015 was highest at Seoguipo, and was followed by Daegu, Jejusi, Gwangju and Jeonju. The average voltinism from 1966 to 2015 was lowest at Ulreundo. The voltinism of R. pedestris observed the last 50 years was attributable to human activities at some locations.

• Jeong Joon Ahn(Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, RDA)
• Kyoung San Choi(Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, RDA)
• Sang Woog Kho(Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, RDA)