A new bulletin from University of Wyoming Extension provides information on how to combat an insect that damages an important forage grass seed crop for Wyoming farmers and ranchers.

Smooth bromegrass was brought to North America from Europe in the late 1800s and has become a key pasture grass in Wyoming, along with being used in vegetation restoration. But the introduction of the nonnative grass also brought the brome seed midge, which causes serious damage to smooth bromegrass — sometimes resulting in complete loss of the high-value seed crop.

The UW bulletin, available at www.tinyurl.com/yu4mkwj9, details the characteristics and life cycle of the midge, explaining how it attacks and damages smooth bromegrass seed production. Most importantly, it describes ways to manage the pest — through both chemical control and correctly timed burning of smooth bromegrass crop residue in fields.

The bulletin was produced by Scott Schell, UW Extension entomology specialist; Jeremiah Vardiman, UW Extension agriculture and horticulture educator; Gary White, retired from Allied Seed LLC; and Mike Moore, manager of UW’s Wyoming Seed Certification Service.

There is a predator, a tiny parasitoid wasp, whose larvae attack the larvae of the brome seed midge. However, those attacks take place after the midge larvae have already severely damaged the developing seeds of smooth bromegrass. Despite wasp parasitism rates of up to 75% of the midge larvae, seed production is still reduced to an unprofitable level.