Seasonal population dynamics of bermudagrass mite and associated mites in turf

Bermudagrass mite infestation causes distorted growth, poor stem and root development, and plant death in bermudagrass grown as turfgrass or hay. Its ecology is largely unknown but crucial to developing an effective management program. In this study, we monitored bermudagrass mite damage and populations to determine their seasonal dynamics. We also documented other mite taxa associated with bermudagrass mite. To monitor mite damage, we counted the numbers of symptomatic shoots biweekly for 6−18 months at three locations in North and South Carolina. To monitor bermudagrass mite populations, we collected 10 symptomatic and 10 asymptomatic shoots monthly from the same three sites, counted the numbers of mites and eggs, and observed the presence of other mite taxa in the shoots. Bermudagrass mite damage and populations followed similar patterns overtime at all sites, i.e., rising rapidly to a peak in the spring and collapsing during early summer. During population peaks, we found bermudagrass mites on 30-60% of asymptomatic grass samples. Associated mites (tarsonemids, tydeids, and others) arrived on dates with peak bermudagrass mite populations and increased until bermudagrass mite populations experienced a sharp decline. This pattern indicates that the population dynamics of bermudagrass mite and these associated mites may be related. The rapid rise in bermudagrass mite damage and populations evident in this study emphasize the difficulty in timely management of this pest. This study provides information to improve monitoring and timing of management strategies against bermudagrass mite.