Zoysiagrass (Zoysia spp.) is a warm-season turfgrass used in home lawns and golf course fairways within the transition zone of turfgrass adaptation and in the southern United States (Fry and Huang, 2004). Cultivars of Z. matrella (L.) Merr., including ‘Cavalier’, ‘Diamond’, and ‘Zorro’ and the cultivar Emerald (Z. japonica × Z. pacifica Goudsw.) are recognized for their high quality; however, they lack freeze tolerance, whereas cultivars of Z. japonica (Steud.) have better freeze tolerance but are generally coarser in texture and lack the quality of Z. matrella cultivars and ‘Emerald’ (Fry and Huang, 2004). Since 2004, researchers at Kansas State University (Manhattan, KS) and Texas AgriLife Research–Dallas (Dallas, TX) have evaluated zoysiagrass progeny associated with reciprocal crosses between Z. japonica × Z. matrella or Z. japonica × ‘Emerald’ for quality characteristics and freeze tolerance. A significant number of these, including those we are reporting here, have demonstrated superior freeze tolerance compared with Z. matrella cultivars or ‘Emerald’ and have improved quality characteristics compared with Z. japonica cultivars including Meyer (Okeyo, 2010). Fortuitously, a natural infestation of the bluegrass billbug (Sphenophorus parvulus Gyllenhal) occurred in 2009 and 2010 in the experimental plots where these zoysiagrasses were being evaluated. As such, this allowed us to compare bluegrass billbug susceptibility of the new freeze-tolerant zoysiagrass progeny with ‘Meyer’.
The bluegrass billbug is the most common insect pest of cool-season turfgrass including kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.). In addition, fine-leaf (Festuca spp.) and tall fescue (Festuca arundinacea Schreb) may be attacked (Hansen, 1987; Kindler and Spomer, 1986; Potter, 1998; Tashiro and Personius, 1970). Bluegrass billbug is native to North America and is present throughout most regions of the United States (Potter, 1998). Adults feed on and deposit eggs in crowns, leaf sheaths, and stems. Eggs hatch into young larvae that cause the most damage when tunneling into stems. Older larvae feed on roots and then pupate in the soil. Bluegrass billbug overwinters as an adult (Potter, 1998).
Studies have evaluated the resistance of cultivars and blends of kentucky bluegrass to the bluegrass billbug (Ahmad and Funk, 1982; Lindgren et al., 1981; Shearman et al., 1983). However, currently, there is minimal information associated with the presence of bluegrass billbug in Kansas and the susceptibility of zoysiagrass. Therefore, the objectives of this study were to monitor the presence of bluegrass billbug larvae at the Rocky Ford Turfgrass Research Center (Manhattan, KS) and determine the susceptibility of zoysiagrass progeny including reciprocal crosses between Z. japonica × Z. matrella or between ‘Emerald’ × Z. japonica to the bluegrass billbug.
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Hansen, J.D. 1987 Seasonal history of bluegrass billbug, Sphenophorus parvulus (Coleoptera: Curculionidae), in a range grass nursery Environ. Entomol. 16 752 756
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Okeyo, D. 2010 Growth characteristics and freezing tolerance of zoysiagrass cultivars and experimental progeny PhD diss., Dept. of Horticulture, Forestry, and Recreation Resources, Kansas State Univ
Reinert, J.A., Engelke, M.C. & Heitholt, J.J. 2010 Hunting billbug resistance among zoysiagrass cultivars USGA Turfgrass and Environmental Research Online 9 1 11
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