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Climate change is predicted to alter the geographic distribution of a wide variety of taxa, including insects. Icerya aegyptiaca (Douglas) and I. purchasi Maskell are two polyphagous and invasive pests in the genus Icerya Signoret (Hemiptera: Monophlebidae) and cause serious damage to many landscape and economic trees. However, the global habitats suitable for these two Icerya species are unclear. The purpose of this study is to determine the potentially suitable habitats of these two species, then to provide scientific management strategies. Using MaxEnt software, the potential risk maps of I. aegyptiaca and I. purchasi were created based on their occurrence data under different climatic conditions and topology factors. The results suggested that under current climate conditions, the potentially habitable area of I. aegyptiaca would be much larger than the current distribution and there would be small changes for I. purchasi. In the future climate change scenarios, the suitable habitats of these two insect species will display an increasing trend. Africa, South America and Asia would be more suitable for I. aegyptiaca. South America, Asia and Europe would be more suitable for I. purchasi. Moreover, most of the highly habitat suitability areas of I. aegyptiaca will become concentrated in Southern Asia. The results also suggested that “min temperature of coldest month” was the most important environmental factor affecting the prediction models of these two insects. This research provides a theoretical reference framework for developing policies to manage and control these two invasive pests of the genus Icerya.

Biosynthesized nanoparticles have a variety of applications, and microorganisms are considered one of the most ideal sources for the synthesis of green nanoparticles. Icerya aegyptiaca (Douglas) is a pest that has many generations per year and can affect 123 plant species from 49 families by absorbing sap from bark, forming honeydew, causing sooty mold, and attracting invasive ant species, leading to significant agricultural losses. The purpose of this work was to synthesize titanium dioxide nanoparticles (TiO 2 -NPs) from marine actinobacteria and evaluate their insecticidal effects on Icerya aegyptiaca (Hemiptera: Monophlebidae), in addition to explaining their effects on protein electrophoresis analysis of SDS‒PAGE proteins from control and treated insects after 24, 72 and 120 h of exposure. In all, seven actinobacterial isolates, the most potent of which has the potential to produce titanium hydroxide-based nanoparticles (TiO 2 -NP2), have DNA sequences that are 99.9% like those of Streptomyces rubrolavendulae (MCN2) according to nucleotide alignment and a phylogenetic tree. The produced TiO 2 -NPs were verified by UV examination and characterized by FT-IR, XRD, TEM, EDX, and DLS analyses. Toxicological results revealed that TiO 2 -NPs have insecticidal effects and high mortality rates reaching 55, 62.5, 80 and 95% at TiO2-NPs dose 120,250,500 and 1000 ppm respectively. Compared with the control, TiO2-NP spraying caused changes in the protein pattern of I. aegyptiaca, as indicated by the disappearance of normal bands and the appearance of other bands, as well as quantitative and qualitative changes in protein content after 24, 72 and 120 h of exposure. The application of TiO 2 -NPs by MNC2 offers a new alternative strategy to control I. aegyptiaca and is considered a modern approach to nanotechnology.

Background Scale insects are worldwide sap-sucking parasites, which can be distinguished into neococcoids and non-neococcoids. Neococcoids are monophyletic with a peculiar reproductive system, paternal genome elimination (PGE). Different with neococcoids, Iceryini, a tribe in non-neococcoids including several damaging pests, has abdominal spiracles, compound eyes in males, relatively abundant wax, unique hermaphrodite system, and specific symbionts. However, the current studies on the gene resources and genomic mechanism of scale insects are mainly limited in the neococcoids, and lacked of comparison in an evolution frame. Result We sequenced and de novo assembled a transcriptome of Icerya aegyptiaca (Douglas), a worldwide pest of Iceryini, and used it as representative of non-neococcoids to compare with the genomes or transcriptomes of other six species from different families of neococcoids. We found that the genes under positive selection or negative selection intensification (simplified as “selected genes” below) in I. aegyptiaca included those related to neurogenesis and development, especially eye development. Some genes related to fatty acid biosynthesis were unique in its transcriptome with relatively high expression and not detected in neococcoids. These results may indicate a potential link to the unique structures and abundant wax of I. aegyptiaca compared with neococcoids. Meanwhile, genes related to DNA repair, mitosis, spindle, cytokinesis and oogenesis, were included in the selected genes in I. aegyptiaca , which is possibly associated with cell division and germ cell formation of the hermaphrodite system. Chromatin-related process were enriched from selected genes in neococcoids, along with some mitosis-related genes also detected, which may be related to their unique PGE system. Moreover, in neococcoid species, male-biased genes tend to undergo negative selection relaxation under the PGE system. We also found that the candidate horizontally transferred genes (HTGs) in the scale insects mainly derived from bacteria and fungi. bioD and bioB , the two biotin-synthesizing HTGs were exclusively found in the scale insects and neococcoids, respectively, which possibly show potential demand changes in the symbiotic relationships. Conclusion Our study reports the first I. aegyptiaca transcriptome and provides preliminary insights for the genetic change of structures, reproductive systems and symbiont relationships at an evolutionary aspect. This will provide a basis for further research and control of scale insects.

Background In this study, an entomogenous, fungus was isolated from the Egyptian mealybug, Icerya aegyptiaca (J.) (Hemiptera: Monophlebidae) on the parasol leaf tree, Macaranga tanarius , in China where evaluated as a biocontrol fungus to reduce the population of the target insect. The strain was identified as Aspergillus parasiticus by morphological and phylogenetic analysisand named ZHKUAP1. The biological characteristics, pathogenicity, and field control effect of the strain were determined. Results The most suitable medium for the mycelial growth of strain ZHKUAP1 was PPDA medium, with an optimum temperature of 30 °C and pH 7, in addition to glucose and peptone as carbon and nitrogen sources. The optimum sporulation conditions were the PPDA medium at 30 °C and pH 6, using the soluble starch and beef extract as carbon and nitrogen sources. The mycelial growth and spore production of strain ZHKUAP1 were stopped at 70 °C and above, indicating that it was not resistant to high temperatures. High concentrations of spore suspension, against young insect age, resulted high corrected mortality, as well as decreased the median lethal time. When the spore concentration was 1 × 10 8 cfu/ml, the corrected mortality of the second nymph was 88.33%, and the LT 50 was 0.66 day. After 10 days of inoculation, the LC 50 of the second instar nymph was the smallest, reaching 4.07 × 10 4 cfu/ml. On the 10th day of the field experiment, the corrected mortality was 76.45%, indicating that the A. parasiticus strain ZHKUAP1 had strong pathogenicity on I. aegyptiaca population. Conclusions The indoor toxicity of the strain to I. aegyptiaca was determined, and the field control effect of the pathogen was explored on this basis. The results have important application prospects in the biological control of I. aegyptiaca.

Background Two photosensitizer agents were used: rose bengal and eosin alone and mixed with soap. Two other chemical compounds were used: active cable oil and soap. All these materials were compared with malathion as a conventional insecticide. The Egyptian mealybug Icerya aegyptiaca attacking ornamental–medicinal plants (acalypha and rose shrubs) and the black Parlatoria scale Parlatoria ziziphus attacking sour orange were evaluated against the tested materials. Results The results obtained suggest that soap, rose bengal mixed, eosin mixed, malathion and active cable oil revealed potency in reducing the population of I. aegyptiaca by 57.24, 87.25, 75.62, 98.71 and 59.91%, respectively, on rose; and by 54.91, 82.64, 62.48, 96.67 and 48.13%, respectively, on acalypha shrubs; their potency on insects showed a significant difference on infested rose than on infested acalypha. The tested compounds revealed lower potency in reducing the population of P. ziziphus than malathion. Reduction percentages were 35.43, 40.39, 34.25, 91.81 and 28.21%, respectively. The accumulation potency of the tested compounds on two insects collectively, without regard to insect species, stages or infested plant species, was assessed at 51.49, 66.18, 55.86, 94.37 and 44.69, respectively. The obtained results confirmed that malathion was the most effective agent against both tested insects, followed by rose bengal mixed with soap, eosin mixed with soap, soap alone and active cable oil. Conclusions The obtained results showed that rose bengal (as a photosensitizers) mixed with soap can be used as a promising agent against all tested insects.