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Determination of phosphine concentration for Cryptolestes ferrugineus (S.) control in wheat in Sonora, Mexico: Poster
Get PDFEfficacy studies on ECO2FUME® phosphine fumigant for complete control of Sitophilus zeamais and Tribolium castaneum in stored maize: Poster
Get PDFECO2FUME® fumigation of maize bag stacks under gas proof sheets was conducted to establish the optimal dosages (application rate) and exposure times (fumigation period) against mixed-age cultures of Sitophilus zeamais and Tribolium castaneum. The Complete Randomized Design (CRD) experimental design was employed, with 3 replications and 4 treatments. The experiments were divided into three groups: 1) treatment with a 25 g/m3 ECO2FUME® application rate (350 ppm phosphine) for 3, 4, and 5 days and a control treatment; 2) treatment with an ECO2FUME® application rate of 50 g/m3 (700 ppm phosphine) for 2, 3, and 4 days and a control treatment; and 3) treatment with a 70 g/m3 ECO2FUME® application rate (1,000 ppm phosphine) for 1, 2, and 3 days and a control treatment. The three target phosphine concentrations of 350 ppm, 700 ppm and 1,000 ppm were maintained during the whole fumigation period. Results of the studies showed that no insect was alive at all dosages and exposure times. The studies also indicated that fumigation with ECO2FUME® could reduce the fumigation period by increasing the phosphine concentration. The effective fumigation protocols on maize against mixed-age cultures of S. zeamais and T. castaneum were ECO2FUME® application rates of 25 g/m3 for 3 days, 50 g/m3 for 2 days and 70 g/m3 for 1 day. The target phosphine concentration must be maintained throughout the fumigation period to achieve 100% mortality of all stages of insects.ECO2FUME® fumigation of maize bag stacks under gas proof sheets was conducted to establish the optimal dosages (application rate) and exposure times (fumigation period) against mixed-age cultures of Sitophilus zeamais and Tribolium castaneum. The Complete Randomized Design (CRD) experimental design was employed, with 3 replications and 4 treatments. The experiments were divided into three groups: 1) treatment with a 25 g/m3 ECO2FUME® application rate (350 ppm phosphine) for 3, 4, and 5 days and a control treatment; 2) treatment with an ECO2FUME® application rate of 50 g/m3 (700 ppm phosphine) for 2, 3, and 4 days and a control treatment; and 3) treatment with a 70 g/m3 ECO2FUME® application rate (1,000 ppm phosphine) for 1, 2, and 3 days and a control treatment. The three target phosphine concentrations of 350 ppm, 700 ppm and 1,000 ppm were maintained during the whole fumigation period. Results of the studies showed that no insect was alive at all dosages and exposure times. The studies also indicated that fumigation with ECO2FUME® could reduce the fumigation period by increasing the phosphine concentration. The effective fumigation protocols on maize against mixed-age cultures of S. zeamais and T. castaneum were ECO2FUME® application rates of 25 g/m3 for 3 days, 50 g/m3 for 2 days and 70 g/m3 for 1 day. The target phosphine concentration must be maintained throughout the fumigation period to achieve 100% mortality of all stages of insects
Field studies with insecticide treated packaging for the control of stored product insects: Presentation
Get PDFRapid detection of phosphine resistance in the lesser grain borer, Rhyzopertha dominica (Coleoptera: Bostrychidae) from China using ARMS-PCR: Poster
Get PDFMThe lesser grain borer, Rhyzopertha dominica is one of the serious cosmopolitan stored grain pests worldwide. High phosphine resistant R. dominica has been reported in several countries. The evolution of strong phosphine resistance is a major challenge for continuous application of the fumigant. Rapid detection of phosphine resistance level is a prime key to implement an appropriate strategy for control the stored-product pests. Dihydrolipoamide dehydrogenase (DLD) is a key metabolic enzyme mediating the phosphine resistance in population of R. dominica, Tribolium castaneum and Caenorhabditis elegans. Analysis of the DLD sequences deposited in GenBank revealed that the P45/49S mutation was the most common one in many PH3-resistant stored-product pest insects. This information now enables direct detection of resistance using molecular diagnosis in field populations. We herein propose a method for rapid detection of phosphine resistance in R. dominica according to P49S point mutation of the DLD gene. Our data provides evidence that the ARMS-PCR method can be used for early warning of phosphine resistance in R. dominica in field conditions.MThe lesser grain borer, Rhyzopertha dominica is one of the serious cosmopolitan stored grain pests worldwide. High phosphine resistant R. dominica has been reported in several countries. The evolution of strong phosphine resistance is a major challenge for continuous application of the fumigant. Rapid detection of phosphine resistance level is a prime key to implement an appropriate strategy for control the stored-product pests. Dihydrolipoamide dehydrogenase (DLD) is a key metabolic enzyme mediating the phosphine resistance in population of R. dominica, Tribolium castaneum and Caenorhabditis elegans. Analysis of the DLD sequences deposited in GenBank revealed that the P45/49S mutation was the most common one in many PH3-resistant stored-product pest insects. This information now enables direct detection of resistance using molecular diagnosis in field populations. We herein propose a method for rapid detection of phosphine resistance in R. dominica according to P49S point mutation of the DLD gene. Our data provides evidence that the ARMS-PCR method can be used for early warning of phosphine resistance in R. dominica in field conditions
Does the lower concentration of anticoagulants affect the efficacy of rodenticide baits? Poster
Get PDFA commercial method of controlling bedbugs (Cimex lectularius) using CO2 in dwellings: Presentation
No full textAs a result of withdrawing residual insecticides such as organophosphates and carbamates throughout the world, infestation in Cimex lectularius has been dramatically increased in recent years. The ability of this pest to starve for three months and its flattened shape of body enables it to hide in tiny holes/cracks or folds, making it difficult to control. Therefore, as a complementary action, fumigating products like textile products and furniture within the dwellings became a practice in Israel. After the conventional treatment of stripping the room, vacuuming, steaming the mattresses and then spraying with a Pyrethroid – a novel method was developed; instead of steaming the mattress and dry cleaning all textile clothes and products, fumigating all movable furniture and textile products with CO2 inside the dwellings. Based on several scientific papers on the efficacy of CO2 on the bedbugs, this method has been successfully implemented in Israel. All textile products are inserted into a sealed, low permeability fumigation cube for three days of exposure time at room temperature to reach a calculated concentration of 100% CO2. Since textile products absorb some of the CO2, the concentrations quickly drops to about 80%. During the summer of 2017, numerous treatments have been carried out with a 100% success and repeated treatments were not required. This treatment has proved to be a promising method of controlling C. lectularius with no need for evacuation of the residents and saving money and efforts in dry cleaning cloths and textile products. It is highly effective against all life stages of the pest.As a result of withdrawing residual insecticides such as organophosphates and carbamates throughout the world, infestation in Cimex lectularius has been dramatically increased in recent years. The ability of this pest to starve for three months and its flattened shape of body enables it to hide in tiny holes/cracks or folds, making it difficult to control. Therefore, as a complementary action, fumigating products like textile products and furniture within the dwellings became a practice in Israel. After the conventional treatment of stripping the room, vacuuming, steaming the mattresses and then spraying with a Pyrethroid – a novel method was developed; instead of steaming the mattress and dry cleaning all textile clothes and products, fumigating all movable furniture and textile products with CO2 inside the dwellings. Based on several scientific papers on the efficacy of CO2 on the bedbugs, this method has been successfully implemented in Israel. All textile products are inserted into a sealed, low permeability fumigation cube for three days of exposure time at room temperature to reach a calculated concentration of 100% CO2. Since textile products absorb some of the CO2, the concentrations quickly drops to about 80%. During the summer of 2017, numerous treatments have been carried out with a 100% success and repeated treatments were not required. This treatment has proved to be a promising method of controlling C. lectularius with no need for evacuation of the residents and saving money and efforts in dry cleaning cloths and textile products. It is highly effective against all life stages of the pest
Development of sensitive polyclonal antibodies against dominant stored wheat grain fungus for its immunological detection: Presentation
No full textFungal infestation causes deterioration of stored food grains. Most fungal species produce secondary metabolites like aflatoxins which are highly toxic to animals and humans. Aspergillus flavus has been found to be the predominant contaminant in stored wheat grains collected from the godowns of Food Corporation of India, West Bengal. The present study focuses on the development of sensitive polyclonal antibodies (PAbs) for molecular immunological detection of dominant toxigenic fungus. Pure A. flavus isolate was cultured on coconut agar media and its spores were harvested and inactivated by 4% formaldehyde. The inactivated spores were injected into a rabbit along with Freund’s complete/incomplete adjuvant for the development of PAbs. Specificity of the raised antibodies in rabbit serum was examined by enzyme-linked immunosorbent assay (ELISA) using spore proteins as antigen obtained by bead beating method. Out of several proteins (ranging from 10 to 200 kDa present in spore, only two prominent proteins of around 76 kDa and 100 kDa were detected by western blot analysis using raised polyclonal antiserum. The PAbs were purified with protein A column followed by spore proteins conjugated CNBr activated sepharose column for its use in the detection of fungal antigens. This highly purified raised antibody can be used for the development of rapid, sensitive, and accurate techniques (such as dot blot/ELISA) for the detection of toxigenic fungi present in stored wheat grains.Fungal infestation causes deterioration of stored food grains. Most fungal species produce secondary metabolites like aflatoxins which are highly toxic to animals and humans. Aspergillus flavus has been found to be the predominant contaminant in stored wheat grains collected from the godowns of Food Corporation of India, West Bengal. The present study focuses on the development of sensitive polyclonal antibodies (PAbs) for molecular immunological detection of dominant toxigenic fungus. Pure A. flavus isolate was cultured on coconut agar media and its spores were harvested and inactivated by 4% formaldehyde. The inactivated spores were injected into a rabbit along with Freund’s complete/incomplete adjuvant for the development of PAbs. Specificity of the raised antibodies in rabbit serum was examined by enzyme-linked immunosorbent assay (ELISA) using spore proteins as antigen obtained by bead beating method. Out of several proteins (ranging from 10 to 200 kDa present in spore, only two prominent proteins of around 76 kDa and 100 kDa were detected by western blot analysis using raised polyclonal antiserum. The PAbs were purified with protein A column followed by spore proteins conjugated CNBr activated sepharose column for its use in the detection of fungal antigens. This highly purified raised antibody can be used for the development of rapid, sensitive, and accurate techniques (such as dot blot/ELISA) for the detection of toxigenic fungi present in stored wheat grains
Smallholder farmers’ perceptions of aflatoxins in maize in kamuli district, Uganda: Presentation
No full textMoulds infesting local and imported rice (Oryza spp.) in Cameroon: Poster
Get PDFLoss in quality and quantities of rice during storage is an important issue to focus on. Moulds contaminating rice were investigated and their injuries on rice during storage were evaluated. Local and imported rice samples sold in markets and mills were stored for 3 months under laboratory conditions. The contaminated grains were counted and analyzed to characterize storage moulds. All rice samples evaluated were contaminated by moulds, right from sampling date. The quantity of mouldy grains varied from 1.1% for the rice sample from UNVDA to 4.2% rice brand ‘Main dans la Main’. The highest mould infestation in terms of quality and quantity, was recorded on imported rice samples of world rice and ‘Main dans la Main’ 22.3 and 25.3% respectively; meanwhile ‘Tox 3145 parboiled’, Uncle Benz and Neima presented 7.5, 8.9 and8.9% respectively. In general, imported rice samples contained the highest fungal load with a proportion of 65.9% compared to 34.3% for local samples. Among the 67 isolated strains, the genus Aspergillus dominated, followed by Penicillium, Mucor and Circinella with 13.4, 8.9, and 4.4% respectively. Therefore in Cameroon, some locally produced, but mostly some imported rice contain moulds from different genera, which damage rice at different proportions. It is urgent to develop methods to inhibit the growth of potential storage moulds and preserve the quality of rice consumed.Loss in quality and quantities of rice during storage is an important issue to focus on. Moulds contaminating rice were investigated and their injuries on rice during storage were evaluated. Local and imported rice samples sold in markets and mills were stored for 3 months under laboratory conditions. The contaminated grains were counted and analyzed to characterize storage moulds. All rice samples evaluated were contaminated by moulds, right from sampling date. The quantity of mouldy grains varied from 1.1% for the rice sample from UNVDA to 4.2% rice brand ‘Main dans la Main’. The highest mould infestation in terms of quality and quantity, was recorded on imported rice samples of world rice and ‘Main dans la Main’ 22.3 and 25.3% respectively; meanwhile ‘Tox 3145 parboiled’, Uncle Benz and Neima presented 7.5, 8.9 and8.9% respectively. In general, imported rice samples contained the highest fungal load with a proportion of 65.9% compared to 34.3% for local samples. Among the 67 isolated strains, the genus Aspergillus dominated, followed by Penicillium, Mucor and Circinella with 13.4, 8.9, and 4.4% respectively. Therefore in Cameroon, some locally produced, but mostly some imported rice contain moulds from different genera, which damage rice at different proportions. It is urgent to develop methods to inhibit the growth of potential storage moulds and preserve the quality of rice consumed
Characterization of two novel antioxidant tetrahydroxyxanthones from Hypericum seeds and scanning electronmicroscopic investigations of their testa
Get PDFHypericum-Samen wurden kürzlich als natürliche Quelle für eine Reihe von Xanthon-Derivaten beschrieben. In Methanol-Extrakten von H. perforatum und H. tetrapterum konnten per HPLC(DAD)-MSn zwei Hauptkomponenten, die Tetrahydroxyxanthone THX-1 und -2, identifiziert werden, deren genaue Konfiguration bislang unbekannt war. Beide Substanzen wurden deshalb über chromatographische Auftrennung an Polyamid und Kieselgel aus dem Samenextrakt angereichert und mit Hilfe von 1D- und 2DNMR- Techniken eine Strukturanalyse vorgenommen. Durch Synthese von THX-1 und -2 und Vergleich ihrer chromatographischen sowie spektroskopischen/spektrometrischen Eigenschaften mit den natürlichen THX in H. perforatum wurde die exakte Konfiguration als 1,4,6,7-THX (THX-1) und 1,2,6,7-THX (THX-2) bestimmt. Die beiden neuartigen Verbindungen zeigten eine dreifach stärkere Radikalfängerwirkung im DPPH-Test als das wasserlösliche Vitamin E-Derivat Trolox® und sind somit starke Antioxidantien. Ferner konnte durch rasterelektronenmikroskopische Untersuchungen (SEM) die zweilagige Struktur der Hypericum-Samenschale (Testa) gezeigt werden, wobei die Xanthone wahrscheinlich in der sehr dickwandigen, lignifizierten Skerenchymschicht eingelagert sind.Hypericum seeds have recently been identified as a natural source of different xanthone derivatives. Two main constituents, the tetrahydroxyxanthones THX-1 and -2, were identified in methanolic extracts of H. perforatum and H. tetrapterum by means of HPLC(DAD)-MSn methods. However, the exact configuration of both THX was unknown so far. For this reason, the two compounds were enriched by chromatography on polyamide and silica, and the corresponding fraction was investigated by 1D- and 2D-NMR techniques. Based on a tentative structural assignment a total synthesis of THX-1 and -2 was performed. Comparing the chromatographic and spectroscopic/spectrometric features of synthetic THX-1 and -2 with their natural counterparts their exact configuration was determined as 1,4,6,7-THX (THX-1) and 1,2,6,7-THX (THX-2), respectively. The novel compounds exhibited a threefold higher radical scavenging activity in the DPPH assay than the vitamin E derivative Trolox®. Hence, they are strong antioxidants. Furthermore, scanning electron microscopy (SEM) provided insights into the two-layer structure of the testa (seed coat), with the thick lignified sclerenchyma layer presumably being the depository of the xanthones