Evaluation of Eutetranychus palmatus (Acari: Tetranychidae) as a pest of date palms in Israel.
The spider mite Eutetranychus palmatus Attiah feeds on various palms. The objectives of this study were: (1) to study the phenology of this little-known species and (2) to determine its status as a pest of date fruit. During a three year study (2001-2003), infestations of E. palmatus on fruit strands began earlier than those of the pestiferous old world date mite, Oligonychus afrasiaticus (McGregor), but peak numbers of the latter were invariably much higher than those of E. palmatus. On fronds E. palmatus was observed from mid-winter throughout summer, its highest numbers being recorded from May to early June. Later, in July and August, E. palmatus populations declined. Oligonychus afrasiaticus was seldom found during winter and spring, but maintained small populations on the fronds in summer, concurrent with very large numbers on the fruit strands. Adult cumulative mite day levels of O. afrasiaticus (on fruit strands) were always considerably higher than those of E. palmatus, but on fronds the opposite was observed. Despite the relatively minor pest status of E. palmatus in comparison to O. afrasiaticus, growers who have experienced spider mite damage caused by high populations of E. palmatus very early in the season (April-May) are applying acaricides to treat this pest. The damage potential of E. palmatus is discussed and compared to that of O. afrasiaticus.