Vine and citrus mealybug pest control based on synthetic chemicals. A review

Synthetic chemicals are extensively used to limit the substantial crop damage induced by two closely related scale insects, the vine mealybug Planococcus ficus (Signoret) and the citrus mealybug Planococcus citri Risso (Hemiptera: Pseudococcidae). Both organisms are economically important pests occurring in vineyards and/or in citrus orchards worldwide. Synthetic chemicals can be either incorporated in pesticides aimed at directly controlling these pests or used as semiochemicals (i.e., sex pheromones) for monitoring, mass trapping, mating disruption, and/or for kairomonal attraction to enhance parasitoid performances. Growing evidence of both an alarming bee decline and destruction of auxiliary fauna driven by pesticides have stimulated an urgent need for in-depth research clarifying the adverse side effects of pesticides on beneficial arthropods. We have reviewed the current knowledge on mealybug pest control based on insecticides and semiochemicals. We highlight the following major advances: (1) How the active substances of insecticides (four organophosphates, imidacloprid, buprofezin, and spirotetramat) affect target and non-target organisms, (2) in which contexts and how a semiochemical-based strategy could be applied to deal with serious mealybug infestations, and (3) the implications of the appropriate exploitation of these synthetic chemicals for sustainable development. Using selective insecticides with novel modes of action and long-lasting efficacy in combination with eco-friendly semiochemical-based tools is a promising strategy for developing sustainable integrated pest management programs. This would help to maintain biodiversity dynamics and vital ecosystem services, thereby sustaining crop yields.