Comparative efficacy of seven biorational insecticides to manage African citrus psyllid (Trioza erytreae) in European organic citriculture

ABSTRACT Spain is the number one citrus-producing country in the European Union and the sixth worldwide, with more than six million tons of citrus produced annually. Seven biorational insecticides (paraffin oil, azadirachtin, kaolin, garlic extract, orange oil, potassium soap and diatomaceous earth) recommended for control of different pests in organic citrus orchards were evaluated against Trioza erytreae (Del Guercio) in semi-field and field trials. All products affected T. erytreae survival in both types of trials. In the semi-field trial, diatomaceous earth resulted in the highest percentage mortality of T. erytreae nymphs, followed by kaolin, apart from on the final day of assessment when the highest mortality was recorded for paraffin oil, though this effect was not significantly different to that of the other insecticides. In the 2018 field trial, orange oil treatment resulted in the highest mortality rate of T. erytreae nymphs, followed by azadirachtin and garlic extract. This work provides citrus growers with useful information on the effects of several biorational insecticides on T. erytreae under field and semi-field conditions. Overall, the optimal T. erytreae nymph mortality was achieved with diatomaceous earth and orange oil under semi-field and field conditions, respectively.