Identifying cryptic species of Planococcus infesting vineyards to improve control efforts

Mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) constitute important agricultural pests that often require control measures. Different mealybug taxa might, however, react differently to natural enemies and pesticides so that appropriate control measures against mealybugs rely heavily on the correct species identification. The mealybug Planococcus ficus (Signoret) is the most damaging scale insect infesting vineyards worldwide. Despite its economic impact, the taxonomic status of this mealybug species is still unclear, and recent studies suggest the possibility that P. ficus from eastern (i.e., Egypt) and western (i.e., France) Mediterranean regions may correspond in fact to two distinct species. The purpose of this work was to deepen our current knowledge of putative P. ficus from eastern Mediterranean using molecular tools and morphological analysis and test for the existence of cryptic species within P. ficus. Mealybug samples were collected from Egyptian vineyards to better characterize the genetic diversity and analyze the population structure of putative P. ficus along the eastern Mediterranean. We also estimated the phylogenetic relationships among the P. ficus complex haplotypes in different vineyard regions worldwide and analyzed the morphological characters of the different clades obtained. Morphological and molecular analyses confirmed the existence of two species: P. ficus (Signoret) s.str. and P. vitis (Niedielski), a species that was previously synonymized as P. ficus. These results have direct implications for pest management and could explain the lack of success in previous implementations of biological control programs against this pest in several vineyard regions.