Technical Abstract: The insect pathogenic fungus, Metarhizium anisopliae, has been under study for the control of Tetanops myopae-formis, the sugarbeet root maggot (SBRM) has not been very effective by itself in the face of the heavy insect pressure that routinely occurs in the northern Red River Valley., esp. in the upper Red River Valley. Integration of a microbial biocontrol agent with other pest management tools may provide economic management of pest damage. approach may be to couple an SBRM resistant sugarbeet with the fungus. We conducted small plot field trials in 2003 and 2004 in which a resistant variety, F1015, and a SBRM susceptible variety, Beta 3820, were combined with applications of M. anisopliae. Our goal was to determine whether the fungus would reduce damage (increase yield) to a significantly greater extent in a resistant variety than in a susceptible variety, in the face of heavy insect pressure. There were no significant differences due to Metarhizium applications in root damage or yield, within variety, in either year, even though there were numerical increases in all categories (except percent sugar in the resistant variety). Differences in root damage and yield were significant between the two varieties. Bioassays of post-treatment soils and determination of Metarhizium colony forming units/g soil indicated that there may not have been enough Metarhizium in the larval microhabitat to produce good efficacy.