Management strategies of mealybug pests of citrus in Mediterranean countries

Six mealybug species have been reported as citrus pests in the Mediterranean Basin: the citrus mealybug Planococcus cirri (Risso), the citriculus mealybug Pseudococcus cryptus Hempel, the longtailed mealybug Pseudococcus longispinus (Targioni-Tozzetti), the citrophilus mealybug Pseudococcus calceolariae (Maskell), the obscure mealybug Pseudococcus viburni (Signoret) and the spherical mealybug Nipaecoccus viridis (Newstead). Some of these species, e.g. N. viridis, have recently been introduced into the region and are still spreading. Mealybugs are usually occasional or minor pests of citrus, but some species can reach key pest status. Mealybug management strategies in citrus have been based mostly on classical biological control and, to a lesser extent, on augmentative releases. However, chemical control is widely used, mainly because of the poor adaptation of the principal natural enemies to the climatic conditions of the Mediterranean. The application of pheromones is still restricted to monitoring the citrus mealybug, whose sex pheromone is commercially available. Mass trapping and mating disruption should be considered for possible use in IPM programs as an alternative method to supplementary chemical treatments. Enhancement of biological control through management of ant populations is another promising tactic for control of mealybugs. Strategies for managing mealybug pests of citrus, and possible levels of integration of different tactics according to the pest status, are discussed.