The impact of canopy foraging ants on California red scale Aonidiella aurantiiin a Mediterranean citrus orchard

Abstract: We conducted an ant-exclusion experiment during two years (2007 and 2008) in acitrus orchard in order to evaluate the overall impact of three ant species native to theMediterranean on Aonidiella aurantii (Maskell) (California red scale) populations. The antexclusionwas performed in four experimental plots. In another subset of adjacent four plotsthe ants had access to the canopies (control trees). We monitored populations of the scale onfruits before harvest as well as the percent parasitism between treatments. Additionally,during 2008, monthly samplings (from March to November) of the scale densities on twigsand fruits were also performed. In 2008, significant lower populations of the scale in the antexcludedtrees were observed in May and this difference lasted until November. At harvest,significantly lower population densities of the scale on fruits were recorded on the antexcludedtrees both years of the study. We did not detect differences in the percents ofparasitism between the two treatments.