The soybean tentiform leafminer (STL) has emerged as a new pest of soybean. This research was aimed at providing a foundation for development of an integrated pest management program for this pest. Two important management tactics were examined.

To evaluate chemical control, a field insecticide efficacy experiment was performed in an infested soybean field on a farm near Henderson, MN. Endigo and AgriMek, which have translaminar properties and showed promise for control of this pest the previous year, were further evaluated in this study. Overall infestation levels from this pest were low, which resulted in less than 3% of leaf area mined. More leaf area was mined in the lower canopy compared to upper canopy; but there were no differences in leaf area mined among the insecticide treatments or untreated. However, data from the previous year and complementary laboratory and greenhouse studies showed the potential for translaminar insecticides (e.g., Endigo) to control this pest.

To evaluate biological control, field sampling was performed over the season at two locations in Minnesota with a goal of characterizing the community of parasitic wasps attacking STL and the magnitude of their impact on this pest in soybean fields and corresponding nearby wooded areas containing hogpeanut. Plant samples from soybean and hogpeanut were brought to the laboratory to quantify the level of STL infestation and to rear insects (adult STL and parasitic wasps). Nearly 20 species of parasitic wasps have been found to attack this pest. These data are being analyzed and summarized to compare the communities of parasitic wasps and their resulting levels of parasitism between soybean and hogpeanut and across the state.

Being such a new pest, little is known about the biology and management of STL. This research provides farmers guidance for protecting their soybean crops from this pest through the use of insecticides. In addition, this project establishes foundational knowledge on biological control of STL, which will facilitate the development of more sustainable integrated pest management programs.