Identification of mealybug pest species (Hemiptera: Pseudococcidae) in Egypt and France, using a DNA barcoding approach

Abstract

Pseudococcidae (mealybugs) is a large taxonomic group, including a number of agronomic pests. Taxonomic identification of mealybug species is a recurrent problem and represents a major barrier to the establishment of adequate pest management strategies. We combined molecular analysis of three DNA markers (28S-D2, cytochrome oxidase I and internal transcribed spacer 2) with morphological examination, for the identification of 176 specimens collected from 40 mealybug populations infesting various crops and ornamental plants in Egypt and France. This combination of DNA and morphological analyses led to the identification of 17 species: seven in Egypt (Planococcus citri (Risso), Planococcus ficus (Signoret), Maconellicoccus hirsutus (Green), Ferrisia virgata (Cockerell), Phenacoccus solenopsis Tinsley, Phenacoccus parvus Morrison and Saccharicoccus sacchari (Cockerell)) and 11 in France (Planococcus citri, Pseudococcus viburni Signoret, Pseudococcus longispinus (Targioni-Tozzetti), Pseudococcus comstocki (Kuwana), Rhizoecus amorphophalli Betrem, Trionymus bambusae (Green), Balanococcus diminutus (Leonardi), Phenacoccus madeirensis Green, Planococcus vovae (Nasonov), Dysmicoccus brevipes (Cockerell) and Phenacoccus aceris Signoret), Pl. citri being found in both countries. We also found genetic variation between populations considered to belong to the same species, justifying further investigation of the possible occurrence of complexes of cryptic taxa.

Molecular and Morphological Identification of Mealybug Species (Hemiptera: Pseudococcidae) in Brazilian Vineyards

“…For LCO-19, 28S-09 and 16S-10, we observed hits with similarities of 94, 96 and 97%, respectively, with Pseudococcus comstocki Kuwana from Malausa et al . [23] and Abd-Rabou et al [17].…”

“…Except for the first region of the COI gene (the LCO-HCO region used in most international DNA barcoding projects), for which we used an updated version of the primers [17], we followed the protocol described by Malausa et al . [23].…”

“…Current methods for distinguishing between mealybug species are based on observations of the morphological characteristics of adult female specimens under the microscope. This method is particularly time-consuming, impracticable for males and nymphs, and may be inconclusive, particularly for very closely related species [15]–[17]. This is particularly problematic because difficulties in identification may jeopardize the use of control and management methods specific to certain target species, which are currently favored over the use of broad-spectrum pesticides.…”

“…Several genomic regions have successfully been used for the identification of mealybugs and other scale insects. These regions include 28S-D2 and internal transcribed spacer 2 (ITS2) in the nuclear DNA, the mitochondrial cytochrome oxidase subunit I (COI) gene, and the leuA-16S region located in the DNA of the primary endosymbionts of most Pseudococcidae, Tremblaya princeps [17]–[26]. Furthermore, the DNA sequencing data obtained can be used to develop species-specific Polymerase Chain Reactions (PCR), making it possible to identify species molecularly, on the basis of the size of the sequence amplified [18], [27]–[29].…”

A new species of Dysmicoccus damaging lavender in French Provence (Hemiptera, Sternorrhyncha, Pseudococcidae)

“…The third one, hereafter referred to as COI, is located in the mitochondrial region of Cytochrome Oxidase Subunit I. For COI, we amplified three overlapping fragments previously used in several molecular studies on Pseudococcidae (Malausa et al, 2011;Park et al, 2011;Abd-Rabou et al, 2012), covering in total ~1050 bp. The sequences of the primers used to amplify each region are provided in Table 1. PCR were performed using the Qiagen Multiplex PCR kit (QIAGEN, Hilden, Germany), in a reaction volume of 25 µL.…”