Natural enemies of armored scales (Hemiptera: Diaspididae) and soft scales (Hemiptera: Coccidae) in Chile: Molecular and morphological identification.

Paul Amouroux,Philippe Kreiter,Géraldine Groussier,Antonio Garonna,Carola Roman,Thibaut Malausa,Emilio Guerrieri,Didier Crochard,Tania Zaviezo,Margarita Correa

doi:10.1371/journal.pone.0205475

Abstract

Scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) are key pests of agricultural crops and ornamental plants worldwide. Their populations are difficult to control, even with insecticides, due to their cryptic habits. Moreover, there is growing concern over the use of synthetic pesticides for their control, due to deleterious environmental effects and the emergence of resistant populations of target pests. In this context, biological control may be an effective and sustainable approach. Hymenoptera Chalcidoidea includes natural enemies of scale insects that have been successfully used in many biological control programs. However, the correct identification of pest scale species and their natural enemies is particularly challenging because these insects are very small and highly specialized. Integrative taxonomy, coupling DNA barcoding and morphological analysis, has been successfully used to characterize pests and natural enemy species. In this study, we performed a survey of parasitoids and predators of armored and soft scales in Chile, based on 28S and COI barcodes. Fifty-three populations of Diaspididae and 79 populations of Coccidae were sampled over the entire length of the country, from Arica (18°S) to Frutillar (41°S), between January 2015 and February 2016. The phylogenetic relationships obtained by Bayesian inference from multilocus haplotypes revealed 41 putative species of Chalcidoidea, five Coccinellidae and three Neuroptera. Species delimitation was confirmed using ABGD, GMYC and PTP model. In Chalcidoidea, 23 species were identified morphologically, resulting in new COI barcodes for 12 species and new 28S barcodes for 14 species. Two predator species (Rhyzobius lophantae and Coccidophilus transandinus) were identified morphologically, and two parasitoid species, Chartocerus niger and Signiphora bifasciata, were recorded for the first time in Chile.

Highlights

Scale insects (Hemiptera:Sternorrhyncha: Coccomorpha) are key pests of crops and ornamental plants worldwide
DNA barcoding is a complementary tool for pest identification regardless of sex or developmental stage. This approach has recently been successfully applied to scale insects, with the molecular identification established for armored and soft scales in Chile [7] and for the mealybugs associated with grapes in Chile and elsewhere, worldwide [8,9,10]
cytochrome oxidase subunit I (COI) sequences were shortened for only 10 individuals, with the removal of 5 bp (n = 9) and 31 bp (n = 1) from the start of the sequence

Summary

Introduction

Scale insects (Hemiptera:Sternorrhyncha: Coccomorpha) are key pests of crops and ornamental plants worldwide. Diaspididae, Pseudococcidae, and Coccidae are the three most important families of Coccomorpha, with 421, 259 and 173 genera, respectively [1] The control of these pests is still based essentially on repeated applications of synthetic insecticides, raising concerns about insecticide resistance in pests and possible effects on human health [2,3]. DNA barcoding is a complementary tool for pest identification regardless of sex or developmental stage This approach has recently been successfully applied to scale insects, with the molecular identification established for armored and soft scales in Chile [7] and for the mealybugs associated with grapes in Chile and elsewhere, worldwide [8,9,10]

Methods

Results

Discussion

Conclusion