Citrus Spp Research Articles

Symptomatic Citrus trees reveal a new pathogenic lineage in Fusarium and two new Neocosmospora species.

The diversity of fusaria in symptomatic Citrus trees in Greece, Italy and Spain was evaluated using morphological and molecular multi-locus analyses based on fragments of the calmodulin (CAM), intergenic spacer region of the rDNA (IGS), internal transcribed spacer region of the rDNA (ITS), large subunit of the rDNA (LSU), RNA polymerase largest subunit (RPB1), RNA polymerase second largest subunit (RPB2), translation elongation factor 1-alpha (EF-1α) and beta-tubulin (TUB) genes. A total of 11 species (six Fusarium spp., and five Neocosmospora spp.) were isolated from dry root rot, crown, trunk or twig canker or twig dieback of citrus trees. The most commonly isolated species were Fusarium sarcochroum, F. oxysporum and Neocosmospora solani. Three new Fusarium species are described, i.e., F. citricola and F. salinense belonging to the newly described F. citricola species complex; and F. siculi belonging to the F. fujikuroi species complex. Results of pathogenicity tests showed this new complex to include prominent canker causing agents affecting several Citrus spp. In addition, two new species are described in Neocosmospora, named N. croci and N. macrospora, the latter species being clearly differentiated from most members of this genus by producing large, up to nine-septate sporodochial conidia.

Determination of Volatile Flavour Profiles of Citrus spp. Fruits by SDE-GC-MS and Enantiomeric Composition of Chiral Compounds by MDGC-MS.

Citrus fruits are known to have characteristic enantiomeric key compounds biosynthesised by highly stereoselective enzymatic mechanisms. In the past, evaluation of the enantiomeric ratios of chiral compounds in fruits has been applied as an effective indicator of adulteration by the addition of synthetic compounds or natural components of different botanical origin. To analyse the volatile flavour compounds of Citrus junos Sieb. ex Tanaka (yuzu), Citrus limon BURM. f. (lemon) and Citrus aurantifolia Christm. Swingle (lime), and determine the enantiomeric ratios of their chiral compounds for discrimination and authentication of extracted oils. Volatile flavour compounds of the fruits of the three Citrus species were extracted by simultaneous distillation extraction and analysed by gas chromatography-mass spectrometry. The enantiomeric composition (ee%) of chiral camphene, sabinene, limonene and β-phellandrene was analysed by heart-cutting multidimensional gas chromatography-mass spectrometry. Sixty-seven (C. junos), 77 (C. limon) and 110 (C. aurantifolia) volatile compounds were identified with limonene, γ-terpinene and linalool as the major compounds. Stereochemical analysis (ee%) revealed 1S,4R-(-) camphene (94.74, 98.67, 98.82), R-(+)-limonene (90.53, 92.97, 99.85) and S-(+)-β-phellandrene (98.69, 97.15, 92.13) in oil samples from all three species; R-(+)-sabinene (88.08) in C. junos; and S-(-)-sabinene (81.99, 79.74) in C. limon and C. aurantifolia, respectively. The enantiomeric composition and excess ratios of the chiral compounds could be used as reliable indicators of genuineness and quality assurance of the oils derived from the Citrus fruit species. Copyright © 2017 John Wiley & Sons, Ltd.

Curry leaf smells better than citrus to females of Diaphorina citri (Hemiptera: Liviidae)

The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama has a host range of about 20 species of the family Rutaceae, including Citrus spp. However, few studies have reported on its host preference. This study evaluated the host-choice behavior of ACP in curry leaf (Murraya koenigii L.), through free-choice test and bioassays with a type ‘Y’ olfactometer, and also characterized the volatiles involved in attracting the ACP. In the free-choice test, the number of adults per plant on curry leaf was higher than the number on citrus plants. When the ACP was tested in the olfactometer, the females showed preference for curry leaf over citrus plants. Sixteen volatile compounds were identified in citrus and curry leaves. Qualitative and quantitative differences in the compounds released by citrus and curry leaves were determined. The volatiles present in these hosts may play an important role in the attraction of D. citri. With this information, further studies should be done to develop new management strategies for the ACP.

Effects of Citrus tristeza closterovirus infection on phloem sap and released volatile organic compounds in Citrus macrophylla

Severe Citrus tristeza virus (CTV) infection can induce change in patterns of growth and cellular differentiation in citrus spp. On the other hand, mild CTV strains do not produce any visible symptom in some citrus species. However, it is not clear whether this asymptomatic infection affects the primary and secondary metabolites of citrus plants. In this study, we investigated the effects of CTV-36 (mild stain) on the phloem sap and released volatiles of Citrus macrophylla. The phloem sap was collected by centrifugation and dried under a nitrogen stream. The dried phloem sap was then derivatized with methoxamine hydrochloride in pyridine (MOX) followed by N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA), and was analyzed by gas chromatography-mass spectrometry (GC-MS). Volatiles released from intact young leaves were collected using a solid phase micro extraction (SPME) fiber and were analyzed using GC-MS. Although no visible symptoms were observed on the infected plants, many changes in the phloem sap and released volatile composition were observed. The levels of many amino acids (l-valine, l-threonine, l-lysine, l-asparagine, and γ-aminobutyric acid) and organic acids (oxalic, malic, and citric acid) were higher in CTV-infected plants. Sugar acids were increased, while glucose and sugar alcohols were decreased as a result of CTV infection. Similarly, CTV infection increased some volatiles and decreased others. Interestingly, most of the aldehyde volatiles were affected in CTV-infected plants; decanal and menthadienal were increased, whereas citronellal and isogeranial were decreased. Understanding the interactions between CTV and citrus is of particular interest for the development of this virus as a vector to express antimicrobial peptides or for virus-induced gene silencing.

Virus-vector relationship in the Citrus leprosis pathosystem

Citrus leprosis has been one of the most destructive diseases of citrus in the Americas. In the last decade important progress has been achieved such as the complete genome sequencing of its main causal agent, Citrus leprosis virus C (CiLV-C), belonging to a new genus Cilevirus. It is transmitted by Brevipalpus yothersi Baker (Acari: Tenuipalpidae), and is characterized by the localized symptoms it induces on the leaves, fruits and stems. It occurs in the American continents from Mexico to Argentina. The virus was until recently considered restricted to Citrus spp. However, it was found naturally infecting other plants species as Swinglea glutinosa Merrill and Commelina benghalensis L., and has been experimentally transmitted by B. yothersi to a large number of plant species. Despite these advances little is known about the virus-vector relationship that is a key to understanding the epidemiology of the disease. Some components of the CiLV-C/B. yothersi relationship were determined using the common bean (Phaseolus vulgaris L. cv. ‘IAC Una’) as a test plant. They included: (a) the virus acquisition access period was 4 h; (b) the virus inoculation access period was 2 h; (c) the latent period between acquisition and inoculation was 7 h; (d) the period of retention of the virus by a single viruliferous mite was at least 12 days; (d) the percentage of viruliferous individuals from mite colonies on infected tissues ranged from 25 to 60%. The experiments confirmed previous data that all developmental stages of B. yothersi (larva, protonymph and deutonymph, adult female and male) were able to transmit CiLV-C and that transovarial transmission of the virus did not occur. CiLV-C can be acquired from lesions on leaves, fruits and stems by B. yothersi. Based on the distribution of lesions produced by single viruliferous B. yothersi on bean leaves, it is concluded that they tend to feed in restricted areas, usually near the veins. The short latent and transmission periods during the larval stage suggest that the CiLV-C/B. yothersi relationship is of the persistent circulative type.

Repeats in the transcribed regions: comprehensive characterization and comparison of Citrus spp.

A large number of expressed sequences tags are available for <i>Citrus</i> spp., which provides an opportunity to understand genomic organization of the transcribed regions. Here, we report a detailed analysis of repetitive elements including tandem repeats (TRs) and transposable elements (TEs) in the transcribed region of the <i>Citrus</i> spp. On average, 22% of the expressed sequence tags (ESTs) contain TRs. The relative density of TR classes is highly taxon-specific. For instance, <i>Citrus limonia</i> has a high relative density of mononucleotide repeats, whereas dinucleotide repeats are rare. The proportions of 2–6, 7–30 and 31–50 bp repeats were almost identical in all studied species except for <i>C. limonia</i> and <i>C. limettioides</i>. We found that<1% of the citrus ESTs have a similarity with transposable elements. Transcriptional activity of transposable element families varied even within the same class of elements. A high proportion of transcriptional activity was observed for <i>gypsy</i>-like TEs compare to other TE classes. While TEs are relatively rare, TRs are abundant elements in ESTs of citrus. The high proportion of TRs that have a unit size longer than 6 bp raises the question about a possible functional or evolutionary role of these elements.

Effects of two plant growth promotors on photosynthetic capacity in Citrus spp.

Effects of two plant growth promotors on photosynthetic capacity in Citrus spp.

From Somatic Embryo to Synthetic Seed in Citrus spp. Through the Encapsulation Technology.

In vitro propagation by somatic embryogenesis represents an efficient alternative method to produce high-quality and healthy plants in Citrus species. The regenerated somatic embryos need protection from mechanical damages during manipulation and transport, as well as nutritive support for their evolution in plantlets after sowing. The encapsulation technology allows to obtain synthetic seeds by covering somatic embryos with a gel of calcium alginate enriched by nutrients. This chapter describes the procedure for producing synthetic seeds containing somatic embryos from different Citrus genotypes.

C itrus monstruosa Discrimination among Several C itrus Species by Multivariate Analysis of Volatiles: A Metabolomic Approach

The origin and taxonomy of Citrus monstruosa (Rutaceae) are currently unknown and thus a nontargeted metabolomic analysis on the flavedo volatiles was performed. Headspace solid-phase micro extraction coupled with gas chromatography analysis was applied to eight Citrus spp. including Citrus monstruosa, and the chemical composition of the volatile organic compounds (VOC) was analyzed to give a chemical comparison between different Citrus species. Forty-four metabolites were detected across the species: several monoterpenes were found in all Citrus spp. and among them limonene comes first in all Citrus spp. ranging from 96.7 to 66.7%. Conversely, some molecules were found to be specific for only a few of the samples. The classical univariate evaluation of the VOC data is unlikely to give objective data for the cultivar classification; a multivariate approach, principal component analysis, is an easy to use, powerful tool. Therefore, a chemometric comparison between chromatographic data of all Citrus spp. was performed with the aim of understanding the role of VOC in the discrimination of the eight studied cultivars. Practical Application A chemometrics' method was applied on the volatiles of eight Citrus spp. including Citrus monstruosa. Results were used to discriminate and classify C. monstruosa from several other Citrus spp. This method may also be used to discriminate other Citrus spp. as well as being applied to the volatiles-based classification of other botanicals.

Genome-Wide Characterization and Expression Analysis of Major Intrinsic Proteins during Abiotic and Biotic Stresses in Sweet Orange (Citrus sinensis L. Osb.).

The family of aquaporins (AQPs), or major intrinsic proteins (MIPs), includes integral membrane proteins that function as transmembrane channels for water and other small molecules of physiological significance. MIPs are classified into five subfamilies in higher plants, including plasma membrane (PIPs), tonoplast (TIPs), NOD26-like (NIPs), small basic (SIPs) and unclassified X (XIPs) intrinsic proteins. This study reports a genome-wide survey of MIP encoding genes in sweet orange (Citrus sinensis L. Osb.), the most widely cultivated Citrus spp. A total of 34 different genes encoding C. sinensis MIPs (CsMIPs) were identified and assigned into five subfamilies (CsPIPs, CsTIPs, CsNIPs, CsSIPs and CsXIPs) based on sequence analysis and also on their phylogenetic relationships with clearly classified MIPs of Arabidopsis thaliana. Analysis of key amino acid residues allowed the assessment of the substrate specificity of each CsMIP. Gene structure analysis revealed that the CsMIPs possess an exon-intron organization that is highly conserved within each subfamily. CsMIP loci were precisely mapped on every sweet orange chromosome, indicating a wide distribution of the gene family in the sweet orange genome. Investigation of their expression patterns in different tissues and upon drought and salt stress treatments, as well as with ‘Candidatus Liberibacter asiaticus’ infection, revealed a tissue-specific and coordinated regulation of the different CsMIP isoforms, consistent with the organization of the stress-responsive cis-acting regulatory elements observed in their promoter regions. A special role in regulating the flow of water and nutrients is proposed for CsTIPs and CsXIPs during drought stress, and for most CsMIPs during salt stress and the development of HLB disease. These results provide a valuable reference for further exploration of the CsMIPs functions and applications to the genetic improvement of both abiotic and biotic stress tolerance in citrus.

Ultrastructural changes in the epidermis of petals of the sweet orange infected by Colletotrichum acutatum.

Postbloom fruit drop (PFD) is an important disease caused by the fungus Colletotrichum acutatum. PFD is characterised by the formation of necrotic lesions on the petals and stigmas of flowers as well as premature abscission of the fruit in Citrus spp. We compare the ultrastructure of the epidermis of uninoculated Citrus sinensis petals with that of petals inoculated with the fungus to understand the changes that occur upon C. acutatum infection. Healthy petals have a cuticle with parallel striations covering the uniseriate epidermis. This pattern consists of vacuolated parietal cells whose cytoplasm contains mitochondria, plastids with an undeveloped endomembrane system and a slightly dense stroma, a poorly developed rough endoplasmic reticulum, polysomes, few lipid droplets, and a nucleus positioned near the inner periclinal wall. In damaged regions, the cytoplasm of some cells is densely packed with well-developed endoplasmic reticulum, a large number of hyperactive dictyosomes, numerous mitochondria, and many lipid droplets. The plastids have an electron-dense stroma, starch grains, and a large amount of electron-dense lipid droplets, which can be released into vacuoles or the endoplasmic reticulum. Multivesicular bodies and myelin bodies are frequently observed in the vacuole, cytoplasm, and periplasmic space. Vesicles migrate through the cell wall and are involved in the deposition of cuticular material. In the later stages of infection, there is deposition of new cuticle layers in plaques. The outer periclinal walls can be thick. These observations indicate that epidermal cells respond to the pathogen, resulting in cuticular and parietal changes, which may limit further infection.

Chemical composition of Citrus spp. and oral antimicrobial effect of Citrus spp. peels essential oils against Streptococcus mutans

Introduction: The essential oils of orange peels had a considerable potential to be used as an antimicrobial agent. The aim of this present study is to analized chemical composition of Citrus spp. And the oral antimicrobial effect of Citrus spp. peels essential oils against Streptococcus mutans. Methods: Five orange peels species were used in this study consist of Lime (Citrus aurantifolia), Tangerine (Citrus nobilis), Sweet Orange (Citrus sinensis), Lemon (Citrus limon), and Kaffir Lime (Citrus hystrix). The isolated essential oils were analyzed using gas chromatography-mass spectroscopy (GC-MS). The Streptococcus mutans ATCC 25175 was employed against the antimicrobial effect of samples. Results: The extraction yields of hydrodistilled-essential oils from Tangerine, Kaffir Lime, Sweet Orange, Lemon, and Lime provided the extraction yields of 4.20, 2.26, 1.97, 1.74 and 0.83% yields, respectively. Major component essential oils of Citrus spp. was D-Limonene. The highest antimicrobial activity against S. mutans was Lime peel essential oil, followed by Lemon, Kaffir Lime, and Sweet Orange or Tangerine. All samples showed antimicrobial activity against S. mutans with the variation of antimicrobial action depending on the constituent of D-Limonene, β-Pinene, and α-terpineol. Conclusion: Major component chemical composition of essential oils of Citrus spp. was D-Limonene and antimicrobial activity by Lime peel essential oil due to its proportional amount of D-limonene and β-pinene and the highest antimicrobial activity.

The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses.

Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant's metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant's metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant's resources after infection, but on the other hand, it is a tell-tale sign of the pathogen's presence that triggers the plant to defend itself against infection.

Characterisation of some monofloral Algerian honeys by pollen analysis

In order to contribute to the knowledge of monofloral honeys from northern Africa, a number of 116 honey samples were collected in three areas in the northern region of Algeria and analysed for their melissopalynological characteristics. Fifty-one of them proved to be monofloral and were mainly from four botanical sources: Eucalyptus spp., Hedysarum coronarium, Pimpinella anisum and Citrus spp. The honeys could be differentiated from honeys from neighbouring countries by the presence of specific associated pollen. Besides the main pollen species, the characteristic 12 pollen types in the four monofloral Algerian honeys in this study were: Acacia sp., Brassicaceae, Carduus sp., Centaurea sp., Convolvulus arvensis, Eucalyptus spp., Olea europaea, Papaver rhoeas, Pimpinella anisum, Trifolium spp., Rubus sp. and Vicia sp. Regional differences in the pollen composition were also observed. Characteristic associated pollen grains in the north-western region were Acacia sp., Brassicaceae, Carduus sp. and Centaurea sp., in the central north region Coriandrum sativum, Echium sp. and Trifolium spp. and in the north-eastern region Apiaceae.

Analysis of genetic variability among citrus (Citrus spp) genotypes using morphological traits

Fifty citrus (Citrus spp) genotypes comprising cultivars, strains and hybrids were characterized by using morphological characters in this study. Twenty quantitative characters from leaves, flowers and fruits were evaluated and morphological data from fifty accessions were submitted to one-way ANOVA, principal component and cluster analysis. The matrix of average dissimilarity between genotypes was estimated using Euclidean distance. Significant variation in quantitative characteristics among genotypes was observed. The average distance ranged from 0.09 - 3.77. The clustering pattern clearly differentiates the genotypes into separate clusters based on their dissimilarity values. The first 3 principal components explained 58.72% of variation and identified seeds/fruit, juice content, pH, TSS, TSS:TA and petal size as important traits that can be used to differentiate genotypes. Among all genotypes, small fruited mandarins were highly diverse while sweet orange and grapefruit genotypes presented the lowest diversity. The high diversity observed within the genotypes points to ample possibilities of obtaining desirable trait combinations in specific cultivars.

OBSERVATIONS OF GRAFT COMPATIBILITY BETWEEN CITRUS SPP. AND RELATED AURANTIOIDEAE TAXA

Although Citrus has long been known to be graft compatible with the genus Poncirus, compatibility between other Citrus and other genera of the Aurantioideae is less well characterized. Graft compatibility between Aurantioideae genera has historically been associated with the use of the related taxa as rootstocks for Citrus spp. However, the use of Citrus spp. as rootstocks for related taxa can be useful in maintaining germplasm accessions, in propagating specimen trees or specific commercial taxa, and biological indexing in a sanitation program. One of the largest collections of taxa related to Citrus is maintained by the University of California and the United States Department of Agriculture in Riverside, California. This paper reviews historical observations made in Riverside of graft compatibility between Aurantioideae genera and updates them with current observations. Specific combinations have been observed to be incompatible whereas others have shown either short- or long-term compatibility and survival.

Pummelo in Homestead Garden: Conservation through Family Farming

The pummelo (Citrus grandis Merr.), the largest fruit size in citrus species, is an underutilized fruit in India. Pummelo in Bihar is mostly grown as homesteads and this fruit is to be developed as potential table fruit because of thick rind, easy to handle and transport. Genetic diversity is an important factor in any crop improvement programme for obtaining high yielding cultivars. Variation among seedling progenies is a rule in pummelo since it is monoembryonic Citrus spp. This study was conducted through four cell analysis in the five project communities under the UNEP-GEF project at the Pusa Site, Bihar during 2012 with aim for estimation of genetic diversity for physico-chemical traits, selection of superior clones and to draw the interrelationships between observations for precise characterization of pummelo seedling. Superior plants were also identified based on the highest yield i.e. number of fruits/ plant (> 300). Statistical analysis for physico-chemical parameters revealed significant differences among the selected plants for the 12 horticultural traits indicating the higher variability. Principal Component Analysis (PCA) and cluster dendrogram performed on the basis of studied parameters showed continuous variation in the fruit physico-chemical traits and many groups were formed, indicating existence of large and continuous variation. The first four PCs contributed 68.30% of the variability for fruit quality and PC1 accounted for 30.44% (acidity percentage) followed by fruit length (PC2), fruit width (PC3) etc. The maximum coefficient of variation was found in in case of rind thickness, 100 seed weight and acidity percentage. A large number of variability of pummelo with seedling origin and monoembryonic helps in identification of 4 pummelo clones for pulp colour (2 each for dark red flesh and pink flesh) with excellent eating quality, 9 superior clones were identified for profuse bearing with red fleshed and early. The above variation in the selected pummelo seedlings can be exploited for development of superior varieties, marketing and maintenance of exiting superior clone and above all grower can be ensured livelihood security through homestead farming practices in the community.

FIRST REPORT OF CITRUS PSOROSIS VIRUS IN SYRIA

Citrus psorosis virus (CPsV) is one of the oldest known graft-transmissible viruses of citrus. It causes typical bark scaling lesions in the trunk and limb of sweet orange, mandarin, grapefruit and other citrus spp. During spring 2011, a total of 250 symptomatic and asymptomatic trees, including 100 from a mother block in Lattakia governorate and 150 from six commercial orchards located in Jableh, Tartous and Lattakia areas were sampled to assess the presence of CPsV. All collected samples were analyzed by DAS-ELISA according to Potere et al. (1999) using a commercial kit (Agritest, Italy). Results indicated the presence of CPsV in two Navel Orange trees located in Lattakia. The presence of CPsV was confirmed in these trees by reverse transcription polymerase chain reaction (RT-PCR) using primers consF (5'- ACAAAGAAATTCCCTGCAAGGG-3') and consR (5'-AAGTTTCTATCATTCTGAAACCC-3') that target part of the CPsV coat protein gene (Roy et al., 2005) with the amplification of the expected size (411 bp) DNA product. The RT-PCR product was cloned and sequenced. The sequence of CPsV isolate SYR-C7 (GenBank accession No. HG964696) showed 97% nucleotide identity with Italian CPsV isolates (GenBank accession Nos AM235964 and AY194917). Symptoms associated to CPsV were observed in Syria (Bove, 1995) but the causal agent had yet to be identified. To our knowledge, this is the first CPsV detection in Syria by serological and molecular assays.

Anti-mosquito plants as an alternative or incremental method for malaria vector control among rural communities of Bagamoyo District, Tanzania.

BackgroundPlants represent one of the most accessible resources available for mosquito control by communities in Tanzania. However, no documented statistics exist for their contribution in the management of mosquitoes and other insects except through verbal and some publications. This study aimed at assessing communities’ knowledge, attitudes and practices of using plants as an alternative method for mosquito control among selected communities in a malaria-prone area in Tanzania.MethodsQuestionnaires were administered to 202 respondents from four villages of Bagamoyo District, Pwani Region, in Tanzania followed by participatory rural appraisal with village health workers. Secondary data collection for plants mentioned by the communities was undertaken using different search engines such as googlescholar, PubMED and NAPRALERT.ResultsResults showed about 40.3% of respondents used plants to manage insects, including mosquitoes. A broad profile of plants are used, including “mwarobaini” (Azadirachta indica) (22.5%), “mtopetope” (Annona spp) (20.8%), “mchungwa/mlimau” (Citrus spp) (8.3%), “mvumbashi/uvumbati” (Ocimum spp) (7.4%), “mkorosho” (Anacadium occidentale) (7.1%), “mwembe” (5.4%) (Mangifera indica), “mpera” (4.1%) (Psidium spp) and “maganda ya nazi” (4.1%) (Cocos nucifera). Majority of respondents collected these plants from the wild (54.2%), farms (28.9%) and/or home gardens (6%). The roles played by these plants in fighting mosquitoes is reflected by the majority that deploy them with or without bed-nets (p > 0.55) or insecticidal sprays (p >0.22). Most respondents were aware that mosquitoes transmit malaria (90.6%) while few respondents associated elephantiasis/hydrocele (46.5%) and yellow fever (24.3%) with mosquitoes. Most of the ethnobotanical uses mentioned by the communities were consistent with scientific information gathered from the literature, except for Psidium guajava, which is reported for the first time in insect control.ConclusionThis survey has indicated some knowledge gap among community members in managing mosquito vectors using plant. The communities need a basic health education and sensitization for effective exploitation of this valuable tool for reducing mosquitoes and associated disease burdens. On the other hand, the government of Tanzania should strengthen advocacy of botanical pesticides development, registration and regulation for public health benefits because they are source of pest control tools people rely on them.

Biological and chemo-diverse characterization of Amazonian (Ecuador) Citrus petitgrains

S ix Ama z onian petitgrains samples from C. nobilis Lour. , C. aurantium L. , C. limon L. and mixture of Citrus spp. (Rutaceae), named CN, CA, CL1, CL2, C1 and C2, were chemically characterized by GC-MS and 13 C NMR and evaluated for antioxidant acitivity ( DPPH and b -carotene bleaching tests), for antimicrobial properties ( disk diffusion method) and for antifungal capacity ( agar vapour assay) . CN, C1, C2 samples evidenced the most interesting results: CN ( g -terpinene/linalool chemotype: 14.3%/41.6%, with a considerable amount of thymol: 9.0% ), and C1 (linalool, 18.3%; sabinene, 11.6%; thymol, 5.5%), showed relevant antioxidant activity with both DPPH (IC 50 =3.52 and 5.48 mg/ml, respectively) and b -carotene ( IC 50 =0.387and 0.491 mg/ml, respectively). A ntibacterial properties of CN and C1 against P. mirabilis (MIC=0.61 mg/ml for both) and B. subtilis (MIC=0.61 and 0.44 mg/ml, respectively) were most probably due to thymol . C2 (geranial: 34.7%, neral: 33.1%) evidenced a valuable bioactivity against Candida albicans (MIC=0.44 mg/ml). The 50% growth inhibition (IC 50 ) of the dermatophytes T. mentagrophytes and N. cajetani was reached with amounts of C1, C2 and CN less than 4 m l/plate . Bioactivity of Amazonian Citrus spp. CN, C1 and C2 essential oils suggests their potential use as food preservatives or additives in cosmeceuticals as preventive against dermatophytic fungal infections .