Annual bluegrass, Poa annua L., is an important component of the vegetation on golf course greens and fairways throughout Canada and is widely distributed across the world (2). The barley root-knot nematode, Meloidogyne naasi Franklin, infects and damages cereals such as barley (Hordeum vulgare), sorghum (Sorghum vulgare), and wheat (Triticum durum and T. vulgare), mainly in Europe. Of the root-knot species, M. naasi in particular, prefers grasses over other hosts, and infestations of this nematode can reduce the growth and vigor of turfgrasses (1). In July 2005, annual bluegrass at Beaconsfield Golf Club in Pointe Claire (45°26′N, 73°50′W), Quebec showed signs of an unidentified disease. Irregular yellowish/chlorotic patches were observed on the collar of one golf green. Lower turfgrass density in the turf areas with symptoms was noted. When roots were examined under a dissecting microscope, galling was observed. Upon dissection of washed galls, root-knot nematode egg masses and mature females inside the roots were observed. Nematode extractions of the soil from two samples of 50 g from the green and around the collar and perimeter were also done by the modified Baermann pan method. No juveniles were recovered from soil samples from the healthy area and an average of 400 and 1,500 juveniles/kg dry soil were counted in collar and perimeter samples of the patches. Morphological identification of mature females and juveniles were performed and confirmed to be M. naasi. Currently, there are no regulations to control the introduction of this nematode into Canada. To our knowledge, this is the first report of the occurrence of M. naasi in Canada where it is causing noticeable damage to turfgrass in Quebec. A soil survey is currently underway to examine the distribution of this nematode on golf course turfgrasses in Ontario and Quebec.
References: (1) R. Cook and G. W. Yeates. Nematode pests of grassland and forage crops. Pages 305--350 in: Plant Parasitic Nematodes in Temperate Agriculture. K. Evans et al., eds. CAB International, Wallingford, UK, 1993. (2) S. I. Warwick. Can. J. Plant Sci. 59:1053, 1979.
