Abstract: Pezothrips kellyanus (Bagnall) is a new key pest of oranges and lemons in theMediterranean Basin. We monitored both nymph and adult thrips populations from petal fallto the end of the susceptible period in a commercial orange orchard to determine the numberof treatments necessary to keep thrips populations below the economic threshold. Theefficacy of two insecticides (chlorpyrifos and spinosad) against P. kellyanus as well as theirside effects on natural enemies were evaluated. At petal fall, the percentage of fruit occupiedby P. kellyanus nymphs exceeded the economic threshold and insecticides were applied.After this treatment, the threshold was not reached again and, therefore, only one treatmentwas necessary to control the thrips. All treatments reduced the percentage of both occupiedand damaged fruit. Both insecticides decreased the numbers of natural enemies.