Submitted to: Forage and Grazinglands
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/29/2009
Publication Date: 12/14/2009
Citation: Clement, S.L., Bradley, V.L., Elberson, L.R., Bragg, D.E., Phillips, T.D. 2009. Cereal Leaf Beetle Colonizes Grass Germplasm Nurseries and Impacts Seed Production Activities. Online. Forage and Grazinglands. doi:10.1094/FG-2009-1214-01-RS. Interpretive Summary: The U.S. National Plant Germplasm System (NPGS), with activities supported at the federal level by the Agricultural Research Service of the U.S. Department of Agriculture, preserves and distributes agricultural biodiversity for global food security and environmental restoration. A major NPGS facility is the Western Regional Plant Introduction Station (WRPIS) at Washington State University in Pullman, Washington. The grasses, the largest WRPIS collection with more than 20,000 accessions, has long been an important source of grass seed for forage and turf grass breeders, exemplified by yearly distributions (1999-2009) of over 4,500 seed packets to these stakeholders. As important as WRPIS grass collections are for grass breeding, so are grass microbes in the form of Neotyphodium fungal endophytes. These naturally occurring fungi in grass seed have been acquired by scientists and seed companies to develop new grass-novel endophyte combinations that are incapable of producing livestock toxins but able to produce chemicals (specific alkaloids) for desirable agronomic traits such as superior stand persistence and insect resistance. Indeed, the discovery of a novel endophyte in the WRPIS collection by AgResearch scientists in New Zealand led to the development of tall fescue-novel endophyte associations marketed under the trade names MaxQ in North America and MaxP in New Zealand and Australia. This research paper by WRPIS scientists and colleagues at Washington State University and the University of Kentucky shows how important WRPIS grass and Neotyphidum germplasm have been for new cultivar development. This paper also is important because it illustrates the importance of protecting WRPIS nurseries of Neotyphodium infected and uninfected grass accessions from attack by a new invasive insect pest called the cereal leaf beetle.
Technical Abstract: The cereal leaf beetle (CLB), Oulema melanopus (L.) (Coleoptera: Chrysomelidae), colonized grass germplasm nurseries of the USDA, ARS Western Regional Plant Introduction Station (WRPIS) in southeastern Washington. Although 55 (88.7%) of 62 accessions in 2008 nurseries exhibited symptoms of CLB adult feeding, only 17 accessions in the genera Agrostis, Dactylis, Elymus, Lolium, and Phalaris suffered extensive damage (61 to 100% of leaf area of all plants/accession eaten by adults). The heavily damaged accessions recovered and produced seed in 2009. Little or no CLB adult and larval feeding was detected on second-year nursery plants in 2009. Adults fed on nursery plants of an endophyte-infected (E+) tall fescue accession in 2008. In experiments, CLB adults fed and oviposited and larvae developed on E+ Kentucky 31 (KY-31) tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire. These collective results suggest this invasive beetle could attack E+ grass accessions in future WRPIS nurseries. Components of a CLB pest-management program for grass germplasm nurseries include routine surveys to identify a broad range of endophyte-free (E-) and E+ germplasm at risk to CLB-induced feeding damage, insecticidal sprays if required to control damaging beetle populations, and biological control with introduced parasitoids.