Screening and breeding for bermudagrass stem maggot (BSM) resistance using U.S. bermudagrass germplasm

Authors: Anderson, William - Bill; Hancock, Dennis; BAXTER, LISA - University Of Georgia; HUDSON, W - University Of Georgia; RIOS, E - University Of Florida

Submitted to: Grassland International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/15/2021
Publication Date: 10/25/2021
Citation: Anderson, W.F., Hancock, D.W., Baxter, L., Hudson, W., Rios, E.F. 2021. Screening and breeding for bermudagrass stem maggot (BSM) resistance using U.S. bermudagrass germplasm. Grassland International Congress Proceedings. pp. 1-3. https://uknowledge.uky.edu/igc/24/2-3/27/.

Interpretive Summary: Bermudagrass (Cynodon sp.) is an important forage for ruminant animals in many parts of the world. Since 2009 in the southern United States and also in other parts of the world, a new invasive pest has been causing yield losses to growers using bermudagrass as hay. This insect pest, Bermudagrass Stem Maggot (BSM) (Atherigona reversura Villeneuve) has caused hay losses of over 50% if not controlled. A core collection of over 300 forage bermudagrass accessions was visually evaluated in the field for BSM in 2014 and 2015. Tolerant lines and susceptible checks were then evaluated for yield loss due to BSM in a replicated field study by comparing insecticide-sprayed control plots to unsprayed plots in Tifton to measure the amount of yield loss of the genotypes due to the pest. BSM reduced yield of two commonly grown cultivars, Alicia and Russell, by over 40% and Tifton 85 by up to 35%. However, some plant introductions from our germplasm collection exhibited less than 10% yield loss and had dry matter yields comparable to the highest yielding cultivar, Tifton 85. These accessions will be further evaluated and used in plant breeding.

Technical Abstract: Bermudagrass (Cynodon sp.) is an important perennial forage grass grown in many parts of the world. Bermudagrass Stem Maggot (BSM) (Atherigona reversura Villeneuve) is an insect pest that reduces forage yield and nutritive value if it is not controlled. The pest, native to SE Asia, was first documented in North America in 2009 and is now considered invasive. BSM has been observed on stargrass in Central America in recent years (personal observation). A core collection of over 300 forage bermudagrass accessions was evaluated in the field for susceptibility to BSM in 2014 and 2015. Tolerant lines and susceptible checks were then evaluated for yield loss due to BSM in a replicated field study by comparing insecticide-sprayed plots to unsprayed plots in Tifton, GA starting in 2016 continuing through the summer of 2019. For mid to late summer harvests during 2017, BSM reduced yield of Alicia and Russell by over 40% and Tifton 85 by up to 35%. However, some plant introductions from our germplasm collection exhibited less than 10% yield loss and had dry matter yields comparable to Tifton 85. Nutritive value will also be assessed. These accessions will be further evaluated and used in plant breeding.