Citrus blackfly, Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae), is an important agricultural quarantine pest, causing substantial economic losses to citrus and many other cultivated crops. ...Aleurocanthus woglumi is found in tropical and subtropical regions but is presently unknown in Europe and the Mediterranean Basin. We used CLIMEX to model the potential distribution of A. woglumi under an historical climate scenario (centred on 1995), including a spatially explicit irrigation scenario. We found that A. woglumi could potentially invade the Mediterranean Basin, and south-east Asia, including Australia. There is potential for it to invade most of sub-Saharan Africa. Irrigation is revealed as an important habitat factor affecting the potential distribution of A. woglumi, increasing its potential range by 53% in Asia. Under a future climate scenario for 2050, its potential distribution increased across all continents except Africa, where potential range expansion due to relaxation of cold stresses was limited, and was offset by range decrease due to lethal heat or dry stress. As global climates warm, Europe is likely to face a substantial increase in the area at risk of establishment by A. woglumi (almost doubling under the 2050 irrigation scenario). The biosecurity threat from A. woglumi is significant in current citrus production areas and poses a challenge to biosecurity managers and risk analysts.
Plant essential oils (EOs) and a wide range of their individual components are involved in a variety of biological interactions with insect pests including stimulatory, deterrent, toxic and even ...hormetic effects. Both the beneficial and toxic properties of citrus EOs on the Mediterranean fruit fly (medfly) have been experimentally evidenced over the last years. However, no information is available regarding the toxic or beneficial effects of the major components of citrus EOs via contact with the adults of the Mediterranean fruit fly. In the present study, we explored the toxicity of limonene, linalool and α-pinene (3 of the main compounds of citrus EOs) against adult medflies and identified the effects of sub-lethal doses of limonene on fitness traits in a relaxed full diet (yeast and sugar) and in a stressful (sugar only) feeding environment. Our results demonstrate that all three compounds inferred high toxicity to adult medflies regardless of the diet, with males being more sensitive than females. Sub-lethal doses of limonene (LD20) enhanced the lifespan of adult medflies when they were deprived of protein. Fecundity was positively affected when females were exposed to limonene sub-lethal doses. Therefore, limonene, a major constituent of citrus EOs, induces high mortality at increased doses and positive effects on life history traits of medfly adults through contact at low sub-lethal doses. A hormetic-like effect of limonene to adult medflies and its possible underlying mechanisms are discussed.
The profiles of volatile organic compounds (VOCs) emitted from orange fruits infested by
were examined. VOCs were collected from the headspace of oranges immediately, 24 h, 5 days, 8 days, and 13 ...days after oviposition and when larvae exit the fruit by applying either static or dynamic sampling techniques. A total of 32 and 47 compounds were detected in infested orange fruits when using static and dynamic techniques, respectively. Differences in the volatile profile of oranges were observed. Classification models were employed, showing that infested fruits emitted a chemical profile distinct from that of non-infested ones. Limonene was associated with cell disruption. (
β-Ocimene, (
)-4,8-dimethyl-1,3,7-nonatriene, hexyl butanoate, butyl hexanoate, and hexyl hexanoate were the VOCs that were correlated with the infestation of sweet oranges by
.
This systematic review aims to assess how different urbanisation patterns related to rapid urban growth, unplanned expansion, and human population density affect the establishment and distribution of ...Aedes aegypti and Aedes albopictus and create favourable conditions for the spread of dengue, chikungunya, and Zika viruses.
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using the PubMed, Virtual Health Library, Cochrane, WHO Library Database (WHOLIS), Google Scholar, and and the Institutional Repository for Information Sharing (IRIS) databases. From a total of 523 identified studies, 86 were selected for further analysis, and 29 were finally analysed after applying all inclusion and exclusion criteria. The main explanatory variables used to associate urbanisation with epidemiological/entomological outcomes were the following: human population density, urban growth, artificial geographical space, urban construction, and urban density. Associated with the lack of a global definition of urbanisation, several studies provided their own definitions, which represents one of the study's limitations. Results were based on 8 ecological studies/models, 8 entomological surveillance studies, 7 epidemiological surveillance studies, and 6 studies consisting of spatial and predictive models. According to their focus, studies were categorised into 2 main subgroups, namely "Aedes ecology" and "transmission dynamics." There was a consistent association between urbanisation and the distribution and density of Aedes mosquitoes in 14 of the studies and a strong relationship between vector abundance and disease transmission in 18 studies. Human population density of more than 1,000 inhabitants per square kilometer was associated with increased levels of arboviral diseases in 15 of the studies.
The use of different methods in the included studies highlights the interplay of multiple factors linking urbanisation with ecological, entomological, and epidemiological parameters and the need to consider a variety of these factors for designing effective public health approaches.
Aphid species (Hemiptera: Aphididae) are among the most serious pests for citrus cultivation throughout the world causing substantial crop damages. Accurate identification of aphids to the species ...level can be difficult, though being crucial for their effective management. In this study, a molecular diagnostic assay for distinguishing eleven aphid species was developed. A fragment of the mitochondrial Cytochrome Oxidase I (mtCOI) gene was used and a Polymerase Chain Reaction–Restriction Fragment Length Polymorphism (PCR–FLP) analysis with five restriction enzymes, based on DNA sequence polymorphisms, was applied to differentiate the eleven aphid species. This molecular technique allows aphid species at any life stage to be discriminated accurately and simply and can be a useful tool for monitoring the populations of economically important aphid species.
In the current laboratory study, 14 essential oils (EOs) derived from 12 Lamiaceae plant species and their major components were screened for their larvicidal and repellent properties against
Aedes ...albopictus
, an invasive mosquito species of great medical importance
.
The results of toxicity bioassays revealed that the EOs from
Thymus vulgaris
,
Ocimum basilicum
,
Origanum dictamnus
,
Origanum majorana
, and
Origanum vulgare
, as well as their major components (terpenes), namely thymol, carvacrol,
p
-cymene, and
γ
-terpinene exerted the highest larvicidal effect. Essential oils from
Mellisa officinalis
,
Origanum dictamus
,
Mentha spicata
(chem. piperitenone epoxide),
Origanum majorana
, and
Satureja thymbra
were the most potent repellents, with the last two assigned as the best ones. Among the terpenes tested, piperitenone epoxide, carvacrol, thymol, and piperitenone provided the highest level of protection against
Ae. albopictus
adults. Chemical analysis revealed the presence of a high number of terpenes in the EOs, while in most cases, the biological action of the tested EOs and their major components was in consistency. The most effective EOs and terpenes that were identified through the current laboratory bioassays could be used as alternative agents to control larvae and repel adults of
Ae. albopictus.
The plant-pathogenic bacterium Xylella fastidiosa which causes significant diseases to various plant species worldwide, is exclusively transmitted by xylem sap-feeding insects. Given the fact that X. ...fastidiosa poses a serious potential threat for olive cultivation in Greece, the main aim of this study was to investigate the genetic variation of Greek populations of three spittlebug species (Philaenus spumarius, P. signatus and Neophilaenus campestris), by examining the molecular markers Cytochrome Oxidase I, cytochrome b and Internal Transcribed Spacer. Moreover, the infection status of the secondary endosymbionts Wolbachia, Arsenophonus, Hamiltonella, Cardinium and Rickettsia, among these populations, was determined. According to the results, the ITS2 region was the less polymorphic, while the analyzed fragments of COI and cytb genes, displayed high genetic diversity. The phylogenetic analysis placed the Greek populations of P. spumarius into the previously obtained Southwest clade in Europe. The analysis of the bacterial diversity revealed a diverse infection status. Rickettsia was the most predominant endosymbiont while Cardinium was totally absent from all examined populations. Philaenus spumarius harbored Rickettsia, Arsenophonus, Hamiltonella and Wolbachia, N. campestris carried Rickettsia, Hamiltonella and Wolbachia while P. signatus was infected only by Rickettsia. The results of this study will provide an important knowledge resource for understanding the population dynamics of vectors of X. fastidiosa with a view to formulate effective management strategies towards the bacterium.
The present work describes the use of Centrifugal Partition Chromatography (CPC) for the bio-guided isolation of repellent active volatile compounds from essential oils. Five essential oils (EOs) ...obtained from three Pinus and two Juniperus species were initially analyzed by gas chromatography–mass spectrometry (GC/MS) and evaluated for their repellent properties against Aedes albopictus. The essential oil from needles of P. pinea (PPI) presented the higher activity, showing 82.4% repellency at a dose of 0.2 μL/cm2. The above EO, together with the EO from the fruits of J. oxycedrus subsp. deltoides (JOX), were further analyzed by CPC using the biphasic system n-Heptane/ACN/BuOH in ratio 1.6/1.6/0.2 (v/v/v). The analysis of PPI essential oil resulted in the recovery of (−)-limonene, guaiol and simple mixtures of (−)-limonene/β-pheladrene, while the fractionation of JOX EO led to the recovery of β-myrcene, germacrene-D, and mixtures of α-pinene/β-pinene (ratio 70/30) and α-pinene/germacrene D (ratio 65/45). All isolated compounds and recovered mixtures were tested for their repellent activity. From them, (−)-limonene, guaiol, germacrene-D as well the mixtures of (−)-limonene/β-pheladrene presented significant repellent activity (>97% repellency) against Ae. albopictus. The present methodology could be a valuable tool in the effort to develop potent mosquito repellents which are environmentally friendly.
Aedes (Stegomyia) albopictus (Skuse) and Aedes (Stegomyia) cretinus Edwards are closely related mosquito species with common morphological features and bio-ecological similarities. Recent mosquito ...surveillance in Athens, Greece, showed that they are sympatric mosquito species, with Ae. albopictus corrected developing quite higher population densities than Ae. cretinus corrected . The potential of mating interference between these species was investigated by reciprocal and homologous mating experiments in cages under laboratory conditions. In non-choice interspecific crosses (groups of males and females) females of both species produced sterile eggs. Insemination rate was 58% for Ae. cretinus females and only 1% for Ae. albopictus corrected females. Aedes albopictus males were sexually aggressive and inseminated Ae. cretinus females (31%) in choice experiments, where males of one species had access to mate with females of both species. Whereas, interspecific mating of Ae. albopictus corrected females with Ae. cretinus males in the co-occurrence of Ae. cretinus females was weaker (4%). Aedes cretinus females from non-choice crossing with Ae. albopictus corrected or Ae. cretinus males were paired individually with conspecific males. The percentage of fertile Ae. cretinus females was 17.5% when had encaged before with Ae. albopictus corrected males, compared to 100% when Ae. cretinus corrected females were encaged with conspecific males only. Probable ecological consequences of asymmetric mating between these ecologically homologous species in nature are discussed.
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