Molecular Identification of Mealybugs Species (Hemiptera: Pseudococcidae) by qPCR Melting Curve Analysis

Phytophagous quarantine insect pests, such as mealybug species (Hemiptera: Pseudococcidae), generate important economic losses in the worldwide fruit industry by limiting and preventing exports of some products to different destination markets. Thus, it is important to identify them correctly when exporting fresh fruit to other countries. In Chile, molecular techniques such as PCR and qPCR are used to identify six Pseudococcidae species, among which are Pseudococcus calceolariae (Maskell), Pseudococcus cribata (González), Planococcus citri (Risso), Pseudococcus longispinus (Targioni & Tozzetti), Pseudococcus meridionalis (Prado) and Pseudococcus viburni (Signoret). However, these essential but costly techniques can be optimised to decrease reagent costs and increase the robustness of the results obtained. This study develops a more efficient and economical way to identify these insects, including immature states and male adults that cannot be identified through traditional taxonomy. A qPCR melting curve analysis technique was used, and specific primers were developed for the ITS2 rDNA region, allowing the identification of all target species with 100% accuracy. The method also demonstrated potential for identifying additional mealybug species, making it valuable for phytosanitary surveillance.