D3306: Effects of temperature on the development of soybean tentiform leafminer (Macrosaccus morrisella), a new pest of soybean

Soybean tentiform leafminer (STL), Macrosaccus morrisella (Lepidoptera: Gracillariidae), is a small leaf-mining moth native to North America. STL was previously known to feed on two native fabaceous species. The scattered presence of this moth in soybean fields was first noted in Quebec, Canada beginning in 2016, and later infestations were reported in soybean fields in Minnesota, United States beginning in 2021. In 2022, heavy infestations of STL were reported in Minnesota. Little is known about the biology of this new potential pest of soybean. In this present research, we are investigating the developmental from egg to adult of STL in potted soybean plants held in growth chambers at temperatures ranging from 15-30°C. Regression analyses will be used to calculate the lower developmental threshold and degree-days required to develop from egg to adult. Results of this research will improve the understanding of the biology of STL, particularly its seasonal dynamics and response to temperature.