Preliminary assessment of mite infestations on warmseason turfgrasses in Australia

Phytophagous mites were first identified as a problem in warm-season turfgrasses in Australia around 80 years ago. In production turfgrass fields, slower growth and weakening of sod strength by mites can cause serious commercial losses through breakage of harvested rolls. Elsewhere, mite infestation is associated with poor wear resistance coupled with very slow recovery of turf on playing fields, thereby reducing the usage that is possible on such fields. At the same time, knowledge about turfgrass mites is lacking: specifically, which mite group/species is/are causing damage and to which turfgrass species. There has long been an underlying assumption, based mainly on overseas literature, that mites of the family Eriophyidae are the main cause of the distorted growth symptoms frequently seen and attributed to mite damage. During the 2010/11 growing season, an Australia-wide survey was conducted, sampling seven warm-season turfgrass genera to determine the mites present in each case. This paper reports the results of that survey, together with data from more recent mite infestations sampled during the subsequent threeyear period. Based on their frequency of occurrence, tenuipalpid mites from the genus Dolichotetranychus appear to be at least as important as eriophyoid mites on Cynodon spp.; Dolichotetranychus mites were also recorded from two survey samples of Zoysia spp. but not in subsequent sampling. Eriophyoid mites of the genus Aceria were found on Cynodon spp., with possibly a second species on Zoysia species. A number of mixed tenuipalpid/eriophyoid populations have also been found on Cynodon species. A Steneotarsonemus species (Tarsonemidae) was found associated with Pennisetum clandestinum. Grass-webbing tetranychid mites (Oligonychus spp.) also occasionally affect a wide range of warm-season turf and other grasses non-selectively