Evaluation of control measures for Oligonychus afrasiaticus infesting date palm cultivars in the Southern Arava Valley of Israel

Abstract Oligonychus afrasiaticus is the dominant spider mite pest of date fruit in the Southern Arava Valley of Israel. Growers have dusted fruit bunches prophylactically with sulfur (since 1990), applying as many as five treatments per year, but recently its efficacy has declined. Alternative mite control techniques evaluated in this study to decrease pest damage included: (1) Reducing the overwintering populations; (2) Employing physical barriers to prevent ambulatory and airborne mites from reaching fruit bunches; (3) Exploring the option of using indigenous phytoseiids to control the pest; (4) Applying a single properly timed seasonal acaricide, and (5) Post harvest treatments to mitigate any evident mite damage. Control methods 1–3 did not yield satisfactory results. Mite damage was higher on palms (trees) that had their stems (trunks) scorched in the winter and fruit bunch infestation was not prevented by glue barriers or dense netting. Indigenous phytoseiids were not found on fruit between mid-July till the end of August, when pest populations peaked. In contrast, a single treatment with the acaricides fenbutatin oxide, hexythiazox or abamectin, applied when the first mites were found on the fruit, provided seasonal pest control. The post-harvest re-hydration treatment was also effective, increasing the amount of marketable fresh fruit by approximately 20% on the economically important ‘Medjool’ cultivar.