Rapid identification of Ripersiella (= Rhizoecus) hibisci (Kawai & Takagi, 1971) (Hemiptera: Rhizoecidae) with TaqMan probe-based real-time PCR

Ripersiella hibisci (Kawai & Takagi, 1971) is a root mealybug included in the EPPO A1 list of pests recommended for regulation and an EU A1 Quarantine pest list (Annex IIA). This pest causes damage to several species of monocotyledonous and dicotyledonous ornamental and foliage potted plants, especially bonsais. The underground location of R. hibisci makes its detection difficult during phytosanitary controls, and moreover, it can be confused with other non-regulated species of mealybugs (e.g. Planococcus citri, P. ficus, Rhizoecus falcifer, Rhizoecus dianthi). Thus, a molecular test based on real-time PCR was designed for rapid and unambiguous identification of this mealybug. Analytical sensitivity, analytical specificity, repeatability and reproducibility of the test were assessed as part of the validation. The test showed 100% analytical specificity (exclusivity and inclusivity), allowing the target to be distinguished from all non-target species tested (exclusivity); the inclusivity was demonstrated, validating the test on different populations of the pest. The molecular test is an efficient tool for the identification of the root mealybug R. hibisci (in its various life stages), which is particularly useful when a rapid screening of samples is needed to limit or avoid the introduction of the pest.