Farmers advised to scout fields for soybean pest

University of Missouri Extension state crops entomologist Ivair Valmorbida has confirmed a second finding in Missouri of the soybean tentiform leafminer, a new soybean pest.

Valmorbida said Missouri’s second confirmed case was in Macon County on Aug. 19. The first case of this pest in the state was in a Cooper County soybean field in August 2025.

The soybean tentiform leafminer (Macrosaccus morrisella) was detected feeding on soybean in Minnesota in 2021 and has since been detected in South Dakota, North Dakota, Iowa and Nebraska. Valmorbida encourages farmers to scout soybean fields and to contact their local MU Extension agronomist if they suspect the presence of the soybean tentiform leafminer. This pest is a small white larva that turns pale green as it matures. The adult moths are less than 1/4 inch long and have orange and white wings with gray-black marks.