Dipping Technique Research Articles

Photocatalytic degradation of Perchloroethylene by a lab-scale continuous-flow annular photoreactor packed with glass beads carbon-doped TiO2 nanoparticles

In this study, the amount of photocatalytic degradation of perchloroethylene in the gas phase was investigated by a fixed bed continuous-flow tubular photoreactor. The photoreactor consists of a cylindrical glass tube, was filled with glass beads coated with nanoparticles of TiO2, TiO2 doped carbon (TiO2-C). These nanoparticles were synthesized by the sol-gel method and deposited on glass beads using the sol-gel dip technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), and diffuse reflectance spectroscopy (DRS) were used for the characterization of synthesized materials. The effect of different parameters such as relative humidity, residence time, PCE concentration on the photocatalytic degradation process was investigated by ultraviolet irradiation to achieve the highest possible degradation efficiency. The PCE degradation and byproduct species were monitored and identified with a gas chromatography-mass spectrometer device (GC-MS). Under the optimum experimental conditions, the photocatalytic activities of TiO2, TiO2-C were investigated and compared together. The results showed that photocatalytic activity of TiO2 for degradation of PCE was extremely increased when doped with carbon. For TiO2-C catalyst, under UV irradiation (3000 ppm initial PCE concentration, 30% humidity and 1 min residence time) approximately 96% of the initial PCE was degraded.

Investigation of the effect of Sn doping on Al/Sn: ZnS/p-Si diode parameters with C–V and G/ω-V characteristics

In this study, Sn (tin) doped ZnS (zinc sulphide) films have been deposited on the p-type Si (silicon) crystal substrates by the sol-gel dipping technique. The effect of Sn doping in ZnS on diode parameters has been studied via capacitance-voltage (C–V) and conductance-voltage (G/ω-V) measurements in the frequency range of 10 kHz - 1.5 MHz at room temperature. Fermi energy level (EF), carrier concentration (NA), the density of interface states (Nss), barrier heights (ΦB), and built-in potential (Vbi) of the diodes have been obtained by C–V characteristics. Series resistance (Rs) values of diodes have been determined for different frequencies via C–V and G/ω-V measurements.

Effect of chitosan coatings supplemented with chitosan-montmorillonite nanocomposites on postharvest quality of ‘Hom Thong’ banana fruit

The chitosan (CTS) solutions supplemented with chitosan-montmorillonite (CTS-MMT) nanocomposites at various concentrations were prepared for free-standing films by the casting technique. Incorporating 2% CTS-MMT nanocomposites into the free-standing CTS films could improve the water-resistance and oxygen barrier of the film. For the postharvest experiment, CTS and CTS supplemented with CTS-MMT nanocomposite solutions were applied as banana fruit coating by the dipping technique. The CTS supplemented with 2% CTS-MMT showed a significant retarding in peel color change, reduced electrolyte leakage, and MDA content, while CTS coating could maintain fruit firmness and reduce plasma membrane destruction for only the first few days. In addition, the CTS supplemented with 2% CTS-MMT coating could reduce ethylene production and respiration rate of the banana fruit. Overall results suggest that the CTS supplemented with 2% CTS-MMT nanocomposites is a novel coating material for maintaining the postharvest quality of ‘Hom Thong’ banana fruit.

Trend of mosquito (Diptera: Culicidae) monthly distribution in Sanandaj County of Iran

Abstract. Salavati B, Zahirnia AH, Nasirian H, Hamidian SA. 2021. Trend of mosquito (Diptera: Culicidae) monthly distribution in Sanandaj County of Iran. Biodiversitas 22: 4705-4715. Mosquitoes are the most significant arthropods of medical importance due to their burden of transmitting pathogens and parasites. The present study was designed to investigate the distribution of mosquitos (Diptera: Culicidae) in Sanandaj County in 2018. Sanandaj County was divided into four areas in rural and urban areas, including north, south, east, and west. Four rural and urban areas were randomly selected from four geographical directions. A sampling of larval and adult mosquitoes was performed using standard methods. The dipping technique was used to collect the mosquito larvae. A sampling of adult mosquitoes was performed during feeding on humans and animal baits and resting in the natural indoors, outdoors, and artificial areas. Light traps were also used to collect adult mosquitoes. The larval and adult specimens were identified using the morphology-based key. In total, nine mosquito species, including Anopheles maculipennis s.l., Anopheles superpictus s.l., Culiseta longiareolata, Culiseta subochrea, Culex hortensis, Culex mimeticus, Culex modestus, Culex pipiens, and Culex theileri were inhabited in Sanandaj County. The larval and adult mosquito species trend remains constant for at least 6 months of a year, from May to October. One-way ANOVA didn't reveal a significant difference between mosquito breeding places' habitats and water types, mosquito localities and life stages, monthly mosquito distribution, and adult mosquito resting places. The frequency trends of larval and adult mosquito species remain constant at least for 6 months of a year. It needs to be ready for timely mosquito control measures.

Improvement of expired insecticides and their effectiveness against the cotton leafworm, Spodoptera littoralis (Boisd.)

ObjectivesThis study aimed to recycle some expired insecticides and evaluate their effectiveness against the cotton leaf worm, Spodoptera littoralis (Boisd.) as a tactic to dispose of these obsolete insecticides. MethodsThe physical and chemical characteristics of chlorpyrifos (Chlorzane 48% EC), malathion (Nasr-lathion 57% EC) and cyhalothrin (Lambda-cyhalothrin 5% EC) insecticides were determined. The active ingredients of the tested compounds were estimated by gas–liquid chromatography (GLC) equipped with a flame photometric detector GC/FPD and the insecticidal efficacy against the 4th instar larvae of the cotton leafworm, S. littoralis (Boisd.) was evaluated by the leaf dipping technique. ResultsThe physical and chemical characteristics of the tested insecticides clarified that chlorpyrifos (Chlorzane 48% EC) succeeded in the stability of emulsion, while cyhalothrin (Lambda-cyhalothrin 5% EC) and malathion (Nasr-lathion 57% EC) failed the test, whether unexpired or expired. The emulsifiers, Tween 80 or Triton X-100 at a concentration of 20%, managed to improve the characterizations of the expired insecticides, cyhalothrin and malathion. Moreover, these emulsifiers investigated a promising increase in the efficiency of expired cyhalothrin against S. littoralis. ConclusionsThe emulsifiers, Tween 80 or Triton X-100 could be used to increase the efficiency of expired insecticides, especially cyhalothrin 5% EC, thus managing to apply and dispose of that outdated insecticide.

Functionalized silver nanoparticle-decorated paper sensor for rapid colorimetric detection of copper ions in water

Copper contamination to water bodies is an environmental concern of significant risk due to its harmful effect on aquatic life forms and human beings. Herein, a paper-based colorimetric sensor was fabricated by immobilizing polyethyleneimine-capped silver nanoparticles (PEI-AgNPs) on commercial filter paper. The sensitivity and selectivity of the paper-based sensor’s colorimetric response to copper ions in water were investigated. PEI-AgNPs with an average diameter of 12.66 ± 4.07 nm were successfully immobilized on the filter paper by the simple dipping technique, as evidenced by the scanning electron microscopy with energy-dispersive x-ray result. A color change from pale yellow to dark yellow green was noted after exposing the paper sensor in a water sample with copper ions. This colorimetric response was exclusively observed for copper ions only, suggesting the selectivity of the paper sensor towards copper ions. Moreover, ultraviolet–visible spectroscopy results revealed that the detection limit of the paper sensor was observed to about 1.0 ppm. Meanwhile, color analysis on the sensor’s digital images revealed the linear response of the sensor with decreasing copper ion concentration down to 1.0 ppm. The selectivity of the sensor was also observed by the color intensity profile of the sensor. This work presents promising results that can be utilized as a reference for developing affordable, fast, portable, and reliable sensing devices for on-site water quality monitoring and other applications.

Acorus calamus-zinc oxide nanoparticle coated cotton fabrics shows antimicrobial and cytotoxic activities against skin cancer cells

Microbial infections are a general public health problem worldwide, and their resistance to antibiotics has increased rapidly. The prevention of microbial growth on the surface of cotton fabric is essential to control skin-related infections. In this work, we evaluated A.calamus- zinc oxide nanoparticle (AC-ZnONPs) coated cotton fabrics for antibacterial and cytotoxic activities. The formulated AC-ZnONPs were characterized by UV-spectrophotometer, SEM, EDX, FT-IR, and TEM studies. The AC-ZnONPs amalgamation into the cotton fabrics was done by the dipping technique. The antimicrobial activity and cytotoxic activity were executed by standard approaches. The results of UV-spectrophotometer, TEM, and SEM, and EDX proved the formation and existence of AC-ZnONPs on the fabrics' surface. FT-IR results demonstrated the existence of numerous functional groups. AC-ZnONPs efficiently suppressed the growth of the pathogenic microbes with a maximum inhibition at 60 μg of AC-ZnONPs against E.coli and S.aureus. The AC-ZnONPs coated fabrics also prevented microbial growth with maximum inhibition against P.aeruginosa, K.oxytoca, and A.baumanii. In addition, AC-ZnONPs efficiently suppressed the viability of SK-MEL-3 cells. Altogether, our findings disclosed that the AC-ZnONPs coated fabrics displayed excellent antimicrobial activity against the pathogenic microbes and could be utilized in the medical fields in the future.

Anti-corrosive superhydrophobic coatings fabricated by a simple dipping method

ABSTRACT The two-step dipping technique was used to fabricate anti-corrosive fluorocarbon paint (FP)/SiO2 superhydrophobic coatings on the surfaces of aluminium alloy substrates. In order to characterise the surface microtopography, chemical element and groups, hydrophobicity, and corrosion performance of these prepared coatings, we employed a scanning electron microscope (SEM) and X-ray photoelectron spectrometer (XPS) as well as performing electrochemical experiments. Coating adhesion was reflected by the scotch-tape test. The coatings had a micron–nanometre hierarchical structure, and their surface morphologies were strongly dependent on the silica nanoparticle concentration. The superhydrophobicity of the coating was correlated with its microstructure and composition. The electrochemical experiments revealed that the obtained coating could enhance the corrosion performance of the underlying Al alloy substrates.

Effects of Different Bio-Rational Compounds on Mortality of Diamond Back Moth (Plutella xylostella L.) Larva under Laboratory Condition

A leaf dip technique of bioassay for mortality of DBM larvae was conducted in laboratory condition with room temperature of 25±2°C, relative humidity of 80±3% and 13:11 ratio of Light: dark period at Department of Entomology, Agriculture and Forestry University, Rampur, Chitwan with three replication and eight treatments; i.e. i) Lipel (Bacillus thuriengiensis var. kursataki) 2gm/l, ii) Racer (Beauveria bassiana 1.15% WP) 2gm/l, iii) Derisom (Fractions of Derris indica) 2ml/l, iv) Anosom (Extracts of Annona spp. 1%) 2ml/l, v) Neemix (Neem oil 60% w/w, Azadiractin content less than 300 ppm) 2ml/l, vi) Anthsuper (Chloropyrifos 16% A.I. + Alphacypermethrin 1%EC (w/w) 2ml/l, vii) cow urine (1:5 with water) and viii) control (water spray) in Completely Randomized Design (CRD). The larval mortality was taken after 3, 9, 21, 33, 57 and 93 hours after the treatment application. The larval mortality was found to be significantly higher in Anthsuper treated with 100% mortality of larvae within 33 hours after treatment application followed by cow urine, botanicals (Neemix, Derisom and Anosom) and microbials (Racer and Lipel) where the larval mortality over control was found to ranging from 10% to 47.57% during the experimental period. The larval mortality was 47.57% for Cow urine and Neemix followed by 38.14% for Anosom, 33.29% for Racer, 28.57% for Derisom and 19% for Lipel.it is concluded that chemical pesticide Anthsuper is superior for immediate control of the pest but considering the safety of environment and human health; for long-term control of the pest botanicals and microbials would be more efficient.

Synergistic Efficacy of Plant Essential Oils with Cypermethrin and Chlorpyrifos Against Spodoptera littoralis, Field Populations in Egypt

Background: The essential oils of the plant synergize the synthetic chemical pesticide activity against pests. Controlling pests mainly with synthetic chemical pesticides causes the resistance to build up in these pests like S. littoralis. Methods: This study was conducted to evaluate the synergistic effect of garlic and thymol oils with cypermethrin and chlorpyrifos on field populations of S. littoralis. Also, the impact of the mixtures on activities of three enzymes: Glutathione S-transferase (GST), general esterase (ά-β-EST) and mixed function oxidase (MFO) of S. littoralis using dipping technique. Results: Bioassay shows elevated LC50 for each of cypermethrin and chlorpyrifos alone. Whereas, the toxicity of cypermethrin and chlorpyrifos were synergized 2.81- to 9-fold; 2.74- to 8.35-fold by garlic oil respectively, but far less synergism occurred with thymol oil. The analysis showed the GST, ά-β-EST and MFO were notably inhibited by garlic and thymol oils synergism with cypermethrin and chlorpyrifos in S. littoralis. Conclusions: The results concluded that inhibition of the enzymes could be the result of the synergist of the essential oils when it mixed with synthetic insecticides to control S. littoralis in the field.

Tandem DSSC fabrication by controlled infiltration of organic dyes in mesoporous electrode using electric-field assisted spray technique

Tandem absorber architectures in DSSCs for extending the light absorption range, using two dyes (N719/Red dye and N749/Black dye) appropriately infiltered in the pores of a mesoporous TiO2 photoanode, have been prepared for the first time by electric-field assisted spray technique (E-Spray). In comparison to the conventionally used dip technique, which takes several hours the E-spray technique developed in this study significantly reduces the loading time to 10–15 min by rapid pore filling of dual dyes. The shorter wavelength (450–550 nm) absorber -N719 dye and longer wavelength (550–800 nm) absorber -N749 dye have been infiltrated sequentially and in right proportion by precise control over E-Spray parameters in order to capture a wider range of the incident solar spectrum. The tandem DSSCs (T-DSSCs) thus fabricated show substantial improvement in photo-current density (Jsc), resulting in ~11% enhancement in photoconversion efficiency (PCE), as compared to a single-dye device. The best performing T-DSSC (N719:N749-75:25) yields the Jsc, Voc and FF of ~16 mA/cm2, ~0.75 V and ~0.69, respectively, resulting in PCE of 7.5%, which is ~40% higher than the PCE of 5.33% for the conventionally fabricated dip-coated DSSC. This study opens up door for tandem device fabrication using E-spray technique which is suitable for large area and roll-to-roll manufracturing aiming for high PCE solar cells.

Efficiency of Three Bacterial Strains Against Tetranychus urticae Koch (Acari: Tetranychidae) Under Laboratory Conditions

This study was conducted to evaluate the efficiency of three bacterial strains Pseudomonas aeruginosa, Bacillus subtilis and Lysinibacillus spaericus against adult females of Tetranychus urticae Koch using spraying and dipping techniques with concentrations (101, 103, 105, 107 cfu. ml-1). The mortality percentages were calculated and numbers of each stages resulting from the live treated females were recorded. The symptoms that appear on treated female's mites as a result of death under laboratory conditions were recorded and photographed. The results revealed that, P. aeruginosa caused the highest mortality percentage of adult females T. urticae 100% after 72h at concentration 107 cfu. ml-1 by spraying application. Whereas the mortality percentage which recorded by the dipping technique was 54.58±1.71. B. subtilis also, was recorded increased the average mortality percentage of female T. urticae as it reached 73.33±2.67 in spraying technique compared 41.25±2.08 in dipping technique. While in L. spaericus recorded 62.08±3.41 mortality (%) in spraying technique but at dipping technique the mortality was 27.50±1.61. A sharp decrease was shown in number of stages resulting from lived treated females of T. urticae with P. aeruginosa by four concentrations 101, 103, 105 and 107 by using spraying technique and the life cycle was stopped at the larval stage only at concentration 101 and were not changed into the nymphal stage. While with dipping technique a slight increase in the average number of stages resulting from the adult living females treated with the previously aforementioned concentrations of bacteria P. aeruginosa. The present study cleared that application of bacteria strains on T. urticae adult females either by spraying or dipping techniques lead to some deformations such as, swelling of the body, then fluids exit followed by complete dryness of the body and forward protrusion of the podosoma region and finally death of the adult females

Synthesis and characterization of strontium-doped barium titanate thin film by dip and dry technique

Thin films of polycrystalline (Ba[Formula: see text][Formula: see text]TiO3 ([Formula: see text] = 0.2 and 0.3) with Perovskite structure were prepared by a dip and dry technique on a platinum-coated silicon substrate. The good quality thin films with uniform microstructure and thickness were successfully produced by dip-coating techniques annealed at 730[Formula: see text]C for 1 h. The resulting thin film shows a well-developed dense polycrystalline structure with more uniform grain size distribution. The BST thin films were characterized for their structural, Raman spectroscopy, morphological properties, and complex impedance properties. The dielectric constant-frequency curve showed the good dielectric constant and loss dielectric loss with low-frequency dispersion. The BST 0.3 thin film reveals that the dielectric constant and dielectric loss at a frequency of 1 kHz were 578 and 0.02, respectively. The obtained results on dielectric properties can be analyzed in terms of the Maxwell–Wagner model.

Toxicity and sublethal effects of chlorantraniliprole and indoxacarb on Spodoptera littoralis (Lepidoptera: Noctuidae)

Chlorantraniliprole and indoxacarb insecticides exhibit good efficiency for control lepidopteran pests. The current study is a comprehensive analysis of the effect of lethal and sublethal concentrations of these insecticides on Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) by using the leaf dipping technique. The LC50 values ranged from 0.06 to 1.07 mg/L, and 0.005 to 0.81 mg/L for chlorantraniliprole and indoxacarb, respectively. Our results showed that the treatment of the 2nd instar larvae with LC50 concentrations of these insecticides significantly increased the length of larval and pupal duration as well as pupal weight in most cases. While, no significant differences have been found in the percentage of hatchability except for LC50 equivalent of indoxacarb. Female behavior regarding calling activity decreased by 50–60% following exposure to the LC50 concentration of both insecticides. Gas chromatography analysis results showed that both insecticides lowered pheromone titer except at chlorantraniliprole LC50 equivalent for (Z,E)-9,12-tetradecadien-l-ol acetate, and indoxacarb LC10 equivalent for (Z)-9-tetradecenyl acetate. Additionally, the activity of mixed-function oxidases and glutathione S-transferase were elevated relative to control. The carboxylesterase activity significantly increased when assayed with both chlorantraniliprole concentrations and indoxacarb LC10 equivalent. These results indicate that chlorantraniliprole and indoxacarb could be effective for S. littoralis control.

Alternative Method for Production of Pb Halide Perovskite with High Current Response for Photodetection Devices

To produce functional active layers for photodetector devices, thin films of organic–inorganic CH3NH3PbI3 perovskite semiconductor have been grown by a close-space sublimation procedure and a hybrid dipping technique. x-Ray diffraction analysis was used to evaluate the crystalline quality of the thin films, confirming the achievement of a tetragonal structure of perovskite type in space group I4/mcm. Morphological analysis by scanning electron microscopy revealed a homogeneous and compact granular surface distribution. Kubelka–Munk analysis of the optical response measured by ultraviolet–visible (UV–Vis) spectrophotometry yielded an energy bandgap of 1.57 eV for the thin films produced by the close-space sublimation technique and 1.59 eV for those obtained by dipping. Photoluminescence experiments corroborated these bandgap values. The I–V characteristics of both thin films obtained at different incident laser powers and a wavelength of 650 nm demonstrated their potential for use as active layers in photodetector devices.

Diversity of Mosquitoes (Diptera, Culicidae) and Physico-Chemical Characterization of Their Larval Habitats in Tizi-Ouzou area, Algeria

Many mosquito species are considered as vectors of several pathogens responsible of serious infectious diseases including Malaria, Dengue, Chikungunia and Rift Valley Fever. The characterization of the larval habitat of these arthropods is an important step for a nuisance/vector control program. In this study we aimed to identify mosquito larvae species in the Tizi-Ouzou area (north-central of Algeria) and to examine the physico-chemical parameters of their permanent breeding sites. Surveys are carried out during the dry and rainy seasons (2018/2019), the larval stages of the mosquitoes were sampled using the dipping technique and the physico-chemical parameters of the breeding sites were measured. The morpho-taxonomic examination of the Culicidae samples allowed the identification of 14 species belonging to five genera and two subfamilies. Interestingly, Culex pipiens was the most abundant species found in all entomological surveys. Moreover, Culex pipiens and Culiseta longiareolata species showed high ecological plasticity and were the best correlated species to the studied physico-chemical parameters. Temperature was positively correlated with the density of most inventoried species. Our data would be of great interest in the context of developing a nuisance control program and the prevention of vector-borne diseases.

Implementation of Pre-Milking Udder Preparation to Improve Milk Quality in Small Buffalo Dairy Farm

Pre milking udder preparations play an important role in increasing quality and safety of milk. The objective of this study is to evaluate the effect of implementation of pre milking teat dipping technique by using different chemical sanitizers (Iodophore and Quaternary ammonium compounds QACs). Materials and Methods: Pre-milking udder preparation was carried out in a private small-scale buffalo dairy farm. A total number of 30 dairy buffalo, equal in their milk production and free from clinical and subclinical mastitis, were chosen for this study. They were divided into 3 groups (10 animals each). The first group was used as control group, the second group was treated with Iodophore-based pre-milking udder preparation while, the third group was treated with Quaternary Ammonium Compound-based pre-milking udder preparation. Raw milk samples were collected from individual dairy animals (20 samples) and bulk tank milk (20 samples) after application of the sanitizers for two successive weeks. Each sample was evaluated for prevalence Aerobic mesophilic count, Coliforms, Staphylococci and Enterococci counts. Results: By the end of the second week of application of sanitizers, the count of aerobic mesophilic count, Coliforms, enterococci and staphylococci counts showed reduction% by 30.22, 36.9, 53.17 and 94.38% for Iodophore-treated group while the Quaternary Ammonium Compound treated group showed reduction% by 22.12, 10.70, 17.71 and 85.41%, respectively in comparing with control group. Conclusion: Our study indicated that Iodophore was better than QACs in reducing the microbial counts of tested milk samples as Iodophore efficacy has a long-term residual disinfection including bacterial re-growth and biofilm control.

A Laboratory Study of the Toxicity of Indoxacarb Mixtures against Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

This study, using the combination index (CI) isobologram equation, evaluated the efficacy of indoxacarb in binary mixtures with lufenuron, methoxyfenozide, chlorpyrifos, profenofos, and lambda-cyhalothrin against second instar larvae of Spodoptera littoralis (Boisd.). The efficacy of individual insecticides and their binary mixtures were evaluated using a leaf dipping technique. Percentage mortality was calculated after 72 h of treatment. The results indicated that indoxacarb was highly effective against second instar larvae of S. littoralis where the LC50 was 0.041 mg/l. Lambda-cyhalothrin was the least effective insecticide. Among the five binary mixtures tested, the indoxacarb/chlorpyrifos mixture was the most effective against second instar larvae where the calculated CI values for this mixture were 0.17, 0.12, and 0.21 at LC10, LC25, and LC50, respectively. Latent effects of binary mixtures on some biological parameters of S. littoralis were also evaluated where some of the tested mixtures showed a significant effect on the biological parameters measured.

Study of Abiotic and Biotic Parameters Affecting the Abundance of Mosquito Larvae (Diptera: Culicidae) in the Region of Fez (Morocco)

Mosquitoes cause significant human health issues. However, very few studies have attempted to examine the question of how abiotic and biotic factors affect the abundance of Culicidae in the larval habitat. The objective of this study was to analyze the influence of biotic and abiotic factors on the increase of the most common mosquito species in the Fez region (Central Morocco). Larvae mosquitoes were sampled by standard dipping technique in four different types of macrohabitats, between November 2015 and November 2016. Each mosquito specimen was morphologically identified by the Moroccan Culicidae key and the Brunhes key. The analysis was done using R analysis software. We collected a total of 772 mosquito larvae belonging to nine different species, five of which are considered of medical interest. Culex pipiens (Linnaeus, 1758), known as the major vector in the transmission of West Nile virus fever (WNV), was the most common species of all mosquito larvae collected. The results of Poisson regression analysis showed that factors such as the presence of green filamentous algae, vegetation cover, and debris were found to be positively significant in the distribution of the genus Culex. However, there was insufficient evidence to determine the parameters that are capable of estimating the abundance of Anopheles. The findings have also estimated that biotic and abiotic factors can lead to significant variation in the abundance of Culex perexiguus (Theobald, 1903), Culex theileri (Theobald, 1903), and Culex pipiens (Linnaeus, 1758). Identifying the priority parameters governing the proliferation of mosquitoes in the region of Fez can be one of the key elements for better vector control.

Verticillium wilt of Ailanthus altissima in Italy caused by V. dahliae: new outbreaks from Tuscany

Abstract: Verticillium spp., including V. nonalfalfae and V. dahliae, are known vascular wilt pathogens of the invasive Ailanthus altissima (tree-of-heaven) in the United States and in Europe. Herein we provide evidence of the presence of a previously unreported wilt disease of A. altissima in Tuscany (Central Italy). Several isolates were collected from two locations and identified as V. dahliae, based on microscopical features of conidiophores, conidia and microsclerotia. Genomic DNA was extracted from the mycelium, the ITS region was amplified and the sequence was deposited in GenBank as VdGL16 (accession no. MK474459). BLASTn analysis showed 100% similarity with V. dahliae. To confirm pathogenicity of VdGL16, inoculations of Ailanthus seedlings were performed with the root dipping technique whereas mature trees were stem-inoculated. All inoculated seedlings exhibited wilt symptoms after 20 days, while mature Ailanthus trees showed wilting and dieback after six months. The pathogen was easily re-isolated from seedlings and re-identified as V. dahliae, thus satisfying Koch’s postulates. Results from intraspecific resistance screening of nine seed sources from across Italy revealed that Ailanthus provenances from all the six sampled regions were susceptible to V. dahliae. Stem inoculated adult plants exhibited abundant production of epicormic sprouts along the stem within six months, and most of these sprouts wilted following initial dieback of the main stem; furthermore, sprouting from the crown was intense. Petioles and rachises tissues of leaves fallen from infected trees were a good source for re-isolation of the pathogen; we proved that such petioles and rachises can effectively transfer the fungus to healthy Ailanthus seedlings via root infections. Host-specificity of the V. dahliae isolate VdGL16 was also determined on 40 non-target species/varieties/cultivars. The isolate caused disease in herbaceous species belonging to five botanical families: Asteraceae, Lamiaceae, Leguminoseae, Linaceae and Solanaceae. Given the difficulties in countering Ailanthus invasion with mechanical and chemical methods, the biological control using Verticillium may provide an efficient, low cost and sustainable control of this invasive species.