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Activity of two deltamethrin formulations on different surfaces against rice weevil, Sitophilus oryzae (L.): Poster
No full textSeveral methods are used to control stored product insects. The spraying of empty structures with insecticides, prior to the introduction of produce, is an important method for preventing development of insects. It is known that insecticide activity varies according to the various sprayed surfaces. In this study, the activity of deltamethrin was examined on concrete and plastic surfaces. Deltamethrin is a synthetic pyrethroid, active by contact against a variety of insects; applied in Israel in two formulations: KESHET 2.5% EC and BUNGY 1.5% SC (ADAMA Makhteshim Ltd.). Adults of the rice weevil, Sitophilus oryzae (L.), served as target insect in all experiments. The research was carried out in plastic Petri dishes and in Petri dishes with layer of concrete. Deltamethrin (KESHET 2.5% EC) was applied in water solution in doses of 0.02, 0.1, 0.5 g/m². Without concrete, complete mortality of S. oryzae was obtained at a concentration of 0.02 g/m², whereas in concrete plates, no mortality was found in all 3 concentrations. In contrast, deltamethrin (BUNGY 1.5% SC) in doses of 0.1 g/m², caused 100% mortality with and without concrete layer. The same results were found in the commercial warehouse. No difference in efficiency was found between the spraying methods: airbrush (Sparmax DH-125) or dripping by pipette. The results show that the efficacy of warehouse spraying by deltamethrin depends on its formulation.Several methods are used to control stored product insects. The spraying of empty structures with insecticides, prior to the introduction of produce, is an important method for preventing development of insects. It is known that insecticide activity varies according to the various sprayed surfaces. In this study, the activity of deltamethrin was examined on concrete and plastic surfaces. Deltamethrin is a synthetic pyrethroid, active by contact against a variety of insects; applied in Israel in two formulations: KESHET 2.5% EC and BUNGY 1.5% SC (ADAMA Makhteshim Ltd.). Adults of the rice weevil, Sitophilus oryzae (L.), served as target insect in all experiments. The research was carried out in plastic Petri dishes and in Petri dishes with layer of concrete. Deltamethrin (KESHET 2.5% EC) was applied in water solution in doses of 0.02, 0.1, 0.5 g/m². Without concrete, complete mortality of S. oryzae was obtained at a concentration of 0.02 g/m², whereas in concrete plates, no mortality was found in all 3 concentrations. In contrast, deltamethrin (BUNGY 1.5% SC) in doses of 0.1 g/m², caused 100% mortality with and without concrete layer. The same results were found in the commercial warehouse. No difference in efficiency was found between the spraying methods: airbrush (Sparmax DH-125) or dripping by pipette. The results show that the efficacy of warehouse spraying by deltamethrin depends on its formulation
Comparative lethality of rice husk ash and a diatomaceous eartht adults of four storage beetles: Poster
Get PDFLethality of rice husk ash (RHA) and a diatomaceous earth (SilicoSec) (DE) to adults of Sitophilus zeamais, S. granarius, Lasioderma serricorne and Callosobruchus maculatus was investigated under controlled conditions of 25 ± 2° C and 60 ± 3% relative humidity. Each product was tested at 0.05 g to 0.5 g/20 g of grain respectively in glass Petri dishes against 20 adults of each beetle. Adult mortality was observed up to 10 days post treatment. RHA/DE mixtures (1:1, 3:1 and 1:3 ratios) were also tested at 2% of grain weight. Additionally, RHA and DE were tested at low dosages (0.01 g to 0.04 g/20 g) against adults of C. maculatus alone. The DE generally produced significantly higher mortality of all the adult storage beetles and at earlier observation times, than RHA at the lower dosages (< 0.2 g). Adult mortality produced by RHA and DE in S. zeamais and S. granarius increased with increase in dosage from 0.05 g to 0.5 g. The RHA/DE mixtures generally produced similar mortality of all the adult storage beetles irrespective of post-treatment exposure time. The S. zeamais and S. granarius were generally more tolerant to the DE and RHA treatments than L. serricorne and C. maculatus. Percentage mortality of C. maculatus adults when DE was applied at low dosages (0.01 g to 0.04 g) was generally higher than RHA applied at similar dosages, up to 3 days-post treatment. All treatments produced 100% mortality of C. maculatus adults 4 days-post treatment. The data further confirm the efficacy of DE and RHA as insecticidal dusts at the dosage rate of 0.5 g or more per kg of grain.Lethality of rice husk ash (RHA) and a diatomaceous earth (SilicoSec) (DE) to adults of Sitophilus zeamais, S. granarius, Lasioderma serricorne and Callosobruchus maculatus was investigated under controlled conditions of 25 ± 2° C and 60 ± 3% relative humidity. Each product was tested at 0.05 g to 0.5 g/20 g of grain respectively in glass Petri dishes against 20 adults of each beetle. Adult mortality was observed up to 10 days post treatment. RHA/DE mixtures (1:1, 3:1 and 1:3 ratios) were also tested at 2% of grain weight. Additionally, RHA and DE were tested at low dosages (0.01 g to 0.04 g/20 g) against adults of C. maculatus alone. The DE generally produced significantly higher mortality of all the adult storage beetles and at earlier observation times, than RHA at the lower dosages (< 0.2 g). Adult mortality produced by RHA and DE in S. zeamais and S. granarius increased with increase in dosage from 0.05 g to 0.5 g. The RHA/DE mixtures generally produced similar mortality of all the adult storage beetles irrespective of post-treatment exposure time. The S. zeamais and S. granarius were generally more tolerant to the DE and RHA treatments than L. serricorne and C. maculatus. Percentage mortality of C. maculatus adults when DE was applied at low dosages (0.01 g to 0.04 g) was generally higher than RHA applied at similar dosages, up to 3 days-post treatment. All treatments produced 100% mortality of C. maculatus adults 4 days-post treatment. The data further confirm the efficacy of DE and RHA as insecticidal dusts at the dosage rate of 0.5 g or more per kg of grain
Insecticidal contact toxicity of several essential oils against stored product pests: Poster
Get PDFResults of laboratory bioassays in Petri dishes on evaluation of contact toxicity of Illicium verum, Artemisia absinthium and Abies sibirica essential oils (EOs) against larvae of khapra beetle, Trogoderma granarium Ev., adults of grain weevil, Sitophilus granarius L., and rice weevil, Sitophilus oryzae L., and confused flour beetle, Tribolium confusum Duv., and larvae and adults of the lesser mealworm, Tenebrio molitor L., are presented. EOs commercial samples from retail pharmacy were tested at doses 0.01, 0.25, 0.50, 0.75 and 1.00 µl/cm2. A treated Petri dish surface treted with acetone was used as a control. The experiment was carried out in triplicate. Mortality of insects was assessed after 1, 3, 6 and 24 hours post exposure. After exposure insects were placed into untreated Petri dishes for 3 days. The main components of the A. absinthium EOs are thujil alcohol (19.65%), phellandrene (16.71%), borneol (12.1%) and thujone (11.55%) was found. The major component of I. verum EOs was anethole (98.64%). Isobornyl acetate (57.25%), a-pinene (13.55%) and limonene (10.62%) were found as the main components of A. sibirica EOs. S. oryzae and S. granarius were most sensitive to each EO. I. verum EOs was the most effective and caused 100% mortality of each insect at the dose 0.25 µl/cm2.Results of laboratory bioassays in Petri dishes on evaluation of contact toxicity of Illicium verum, Artemisia absinthium and Abies sibirica essential oils (EOs) against larvae of khapra beetle, Trogoderma granarium Ev., adults of grain weevil, Sitophilus granarius L., and rice weevil, Sitophilus oryzae L., and confused flour beetle, Tribolium confusum Duv., and larvae and adults of the lesser mealworm, Tenebrio molitor L., are presented. EOs commercial samples from retail pharmacy were tested at doses 0.01, 0.25, 0.50, 0.75 and 1.00 µl/cm2. A treated Petri dish surface treted with acetone was used as a control. The experiment was carried out in triplicate. Mortality of insects was assessed after 1, 3, 6 and 24 hours post exposure. After exposure insects were placed into untreated Petri dishes for 3 days. The main components of the A. absinthium EOs are thujil alcohol (19.65%), phellandrene (16.71%), borneol (12.1%) and thujone (11.55%) was found. The major component of I. verum EOs was anethole (98.64%). Isobornyl acetate (57.25%), a-pinene (13.55%) and limonene (10.62%) were found as the main components of A. sibirica EOs. S. oryzae and S. granarius were most sensitive to each EO. I. verum EOs was the most effective and caused 100% mortality of each insect at the dose 0.25 µl/cm2
Binary mixture efficacy of NeemAzal and Plectranthus glandulosus leaf powder against cowpea and maize weevils: Poster
Get PDFThe aim of this study was to determine the insecticidal efficacy of mixture of NeemAzal a commercial neem product and Plectranthus glandulosus leaf powder against Callosubruchus maculatus and Sitophilus zeamais. Mixed at various proportions (100 + 0, 75 + 25, 50 + 50, 25 + 75 and 0 +100%, these powders were tested on adult mortality, inhibition of offspring production and their persistence on C. maculatus and S. zeamais. All the mixed NeemAzal and P. glandulosus caused significant mortality to adult C. maculatus and S. zeamais. No significant difference was observed among the mixed powders that were subjected to the three mixture proportions regarding the mortality they caused to the weevils. The mixed 75% NeemAzal + 25% P .glandulosus of powder led to a higher mortality (100%) of both insect species, three (5 g/kg) days post exposure. The three days LC50 values decreased with ascending proportion of NeemAzal in the mixture from 3.21 g/kg (25% NeemAzal + 75% P. glandulosus) to 0.24 g/kg (75% NeemAzal + 25% P. glandulosus) in S. zeamais. In C. maculatus, the opposing effect was observed. The number of F1 progeny produced reduced significantly (P = 0.01) in both insect species with the mixture proportion of botanicals. The mixtures reduced better the adult progeny production than the botanicals applied alone. The 75% P. glandulosus + 25% NeemAzal persisted well on grains up to 180 days for all dose levels. Powder from NeemAzal and P. glandulosus leaves stand as good candidates to protect maize and cowpea against the infestation of S. zeamais and C. maculatus respectively during storage. Mixing these products could not be advantageous since the binary mixture gave similar result as when they were applied alone.The aim of this study was to determine the insecticidal efficacy of mixture of NeemAzal a commercial neem product and Plectranthus glandulosus leaf powder against Callosubruchus maculatus and Sitophilus zeamais. Mixed at various proportions (100 + 0, 75 + 25, 50 + 50, 25 + 75 and 0 +100%, these powders were tested on adult mortality, inhibition of offspring production and their persistence on C. maculatus and S. zeamais. All the mixed NeemAzal and P. glandulosus caused significant mortality to adult C. maculatus and S. zeamais. No significant difference was observed among the mixed powders that were subjected to the three mixture proportions regarding the mortality they caused to the weevils. The mixed 75% NeemAzal + 25% P .glandulosus of powder led to a higher mortality (100%) of both insect species, three (5 g/kg) days post exposure. The three days LC50 values decreased with ascending proportion of NeemAzal in the mixture from 3.21 g/kg (25% NeemAzal + 75% P. glandulosus) to 0.24 g/kg (75% NeemAzal + 25% P. glandulosus) in S. zeamais. In C. maculatus, the opposing effect was observed. The number of F1 progeny produced reduced significantly (P = 0.01) in both insect species with the mixture proportion of botanicals. The mixtures reduced better the adult progeny production than the botanicals applied alone. The 75% P. glandulosus + 25% NeemAzal persisted well on grains up to 180 days for all dose levels. Powder from NeemAzal and P. glandulosus leaves stand as good candidates to protect maize and cowpea against the infestation of S. zeamais and C. maculatus respectively during storage. Mixing these products could not be advantageous since the binary mixture gave similar result as when they were applied alone
Insecticidal efficacy of abamectin against red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae): influence of dose, exposure interval, relative humidity and temperature: Poster
No full textAssai (Euterpe oleracea Mart.) fruit: Green method development by Andiroba oil (Carapa guianencis L.) for Hemiptera control: Poster
Get PDFUtility of biotechnology based decision making tools in postharvest grain pest management: An Australian case study
Get PDFA major concern for the Australian grain industry in recent years is the constant threat of resistance to the key disinfestant phosphine in a range of stored grain pests. The need to maintain the usefulness of phosphine and to contain the development of resistance are critical to international market access for Australian grain. Strong levels of resistance have already been established in major pests including the lesser grain borer, Rhyzopertha dominica (F.), the red flour beetle, Tribolium castaneum (Herbst), and most recently in the rusty grain beetle Cryptolestes ferrugineus (Stephens). As a proactive integrated resistance management strategy, new fumigation protocols are being developed in the laboratory and verified in large-scale field trials in collaboration with industry partners. To aid this development, we have deployed advanced molecular diagnostic tools to accurately determine the strength and frequency of key phosphine resistant insect pests and their movement within a typical Australian grain value chain. For example, two major bulk storage facilities based at Brookstead and Millmerran in southeast Queensland, Australia, were selected as main nodes and several farms and feed mills located in and around these two sites at a scale of 25 to 100 km radius were selected and surveyed. We determined the type, pattern, frequency as well as the distribution of resistance alleles accurately for two major pests, R. dominica and T. castaneum. Overall, this information along with the phenotypic data, provide a basis for designing key intervention strategies in managing resistance problems in the study area.A major concern for the Australian grain industry in recent years is the constant threat of resistance to the key disinfestant phosphine in a range of stored grain pests. The need to maintain the usefulness of phosphine and to contain the development of resistance are critical to international market access for Australian grain. Strong levels of resistance have already been established in major pests including the lesser grain borer, Rhyzopertha dominica (F.), the red flour beetle, Tribolium castaneum (Herbst), and most recently in the rusty grain beetle Cryptolestes ferrugineus (Stephens). As a proactive integrated resistance management strategy, new fumigation protocols are being developed in the laboratory and verified in large-scale field trials in collaboration with industry partners. To aid this development, we have deployed advanced molecular diagnostic tools to accurately determine the strength and frequency of key phosphine resistant insect pests and their movement within a typical Australian grain value chain. For example, two major bulk storage facilities based at Brookstead and Millmerran in southeast Queensland, Australia, were selected as main nodes and several farms and feed mills located in and around these two sites at a scale of 25 to 100 km radius were selected and surveyed. We determined the type, pattern, frequency as well as the distribution of resistance alleles accurately for two major pests, R. dominica and T. castaneum. Overall, this information along with the phenotypic data, provide a basis for designing key intervention strategies in managing resistance problems in the study area
Australia’s On-Farm Grain Storage Extension Project – a national initiative improving stored grain pest management and maintaining phosphine fumigation efficacy on-farm for the Australian grains industry.: Presentation
No full textPhosphine’s continued use in Australia to control grain insect pests in on-farm and central storage systems is threatened through increased resistance in both frequency and strength in target insect pests. Effective fumigation combined with best practice integrated pest management is essential to the sustainability of grain biosecurity, food safety, quality assurance and market access for Australian post-harvest grain systems. The National Stored Grain Extension Program (NSGEP) is an industry funded initiative developed to facilitate best practice in grain storage management within Australia’s grains industry. The NGSEP uses a multi approach engagement strategy and a variety of adult learning principles and training techniques aimed at increasing awareness and knowledge to build capacity and support to enable farmers and industry to manage their grain storage systems and meet best practice and market requirements. These include: training workshops, field days, practical demonstrations, industry forums, multi-media and website development and building networks with grower groups, government agencies and agribusiness. Various evaluation methods have shown that awareness and adoption of best practice in on-farm grain storage management has increased. Key outcomes include increased knowledge in insect identification and skills development and practice change in the management of grain hygiene, aeration, phosphine application, silo testing and planning of storage systems. The NSGEP contributes to the positive on-going changes observed in Australia’s on-farm grain storage systems, primarily through the specialized extension network of information, support and training provided that is highly regarded and in demand. It plays an instrumental role in building capacity and maintaining phosphine fumigation efficacy in the Australian grains industry.Phosphine’s continued use in Australia to control grain insect pests in on-farm and central storage systems is threatened through increased resistance in both frequency and strength in target insect pests. Effective fumigation combined with best practice integrated pest management is essential to the sustainability of grain biosecurity, food safety, quality assurance and market access for Australian post-harvest grain systems. The National Stored Grain Extension Program (NSGEP) is an industry funded initiative developed to facilitate best practice in grain storage management within Australia’s grains industry. The NGSEP uses a multi approach engagement strategy and a variety of adult learning principles and training techniques aimed at increasing awareness and knowledge to build capacity and support to enable farmers and industry to manage their grain storage systems and meet best practice and market requirements. These include: training workshops, field days, practical demonstrations, industry forums, multi-media and website development and building networks with grower groups, government agencies and agribusiness. Various evaluation methods have shown that awareness and adoption of best practice in on-farm grain storage management has increased. Key outcomes include increased knowledge in insect identification and skills development and practice change in the management of grain hygiene, aeration, phosphine application, silo testing and planning of storage systems. The NSGEP contributes to the positive on-going changes observed in Australia’s on-farm grain storage systems, primarily through the specialized extension network of information, support and training provided that is highly regarded and in demand. It plays an instrumental role in building capacity and maintaining phosphine fumigation efficacy in the Australian grains industry
From narcosis to recovery: development of a rapid diagnostic test for phosphine resistance: Presentation
No full textHydrogen phosphide (PH3) is the most commonly used gas for insect control in durable stored products. One of the quick diagnostic tests that are currently in use is the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK), which has been developed by Detia Degesch GmbH (Laudenbach, Germany). DDPTTK provides a rapid evaluation tool for phosphine resistance, where insects are exposed in syringes that contain a high concentration of gas (e.g. 3000 ppm), while this gas is produced on site by adding tablets into a canister. We used DDPTTK to evaluate resistance of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) to phosphine. For this purpose, we followed a specific succession of observations on the exposed adults of this species, in an effort to set the scene for designing a rapid diagnostic tool for phosphine resistance, based upon quick bioassays. Two T. castaneum strains were used, one susceptible and one resistant to phosphine. Twenty adults of each of the populations (separate sets of adults each time) were placed in syringe of 100 ml under 1000 or 3000 ppm of phosphine. The insects inside the syringe were monitored at 15-min intervals, for a total period of 90 min, and classified as active, under narcosis and immobilized. After this period, all insects were removed from the syringe and placed in plastic petri dishes with a small quantity of wheat flour. The insects were classified again at the three categories above, after 2 h, 1 d, 2 d, 3 d and 7 d. Regarding the exposure period, at 1000 ppm, all adults of the susceptible strain were immobilized after 60 min of exposure, and remained at this condition until the end of the observation period. At the same concentration, the majority of adults of the resistant strain remained active until the end of the observation period. At 3000 ppm, for the susceptible strain, all adults became immobilized after 90 min observation. For the same concentration, the percentage of the adults of the resistant strain that were active was notably reduced in comparison with 1000 ppm. For the post-exposure period, at 1000 or 3000 ppm, for the susceptible strain, the number of adults that were immobilized reached 95 % after 7 d. At the same phosphine concentration, almost all of the adults of the resistant strain were active even at the 2 h post-exposure period, and practically remain at this condition until the end of the observation period. Our findings indicate that time-to-narcosis / immobilization is inversely proportional to time-to-recovery of the same individuals, and this characteristic can be also considered as an indicator for resistance.Hydrogen phosphide (PH3) is the most commonly used gas for insect control in durable stored products. One of the quick diagnostic tests that are currently in use is the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK), which has been developed by Detia Degesch GmbH (Laudenbach, Germany). DDPTTK provides a rapid evaluation tool for phosphine resistance, where insects are exposed in syringes that contain a high concentration of gas (e.g. 3000 ppm), while this gas is produced on site by adding tablets into a canister. We used DDPTTK to evaluate resistance of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) to phosphine. For this purpose, we followed a specific succession of observations on the exposed adults of this species, in an effort to set the scene for designing a rapid diagnostic tool for phosphine resistance, based upon quick bioassays. Two T. castaneum strains were used, one susceptible and one resistant to phosphine. Twenty adults of each of the populations (separate sets of adults each time) were placed in syringe of 100 ml under 1000 or 3000 ppm of phosphine. The insects inside the syringe were monitored at 15-min intervals, for a total period of 90 min, and classified as active, under narcosis and immobilized. After this period, all insects were removed from the syringe and placed in plastic petri dishes with a small quantity of wheat flour. The insects were classified again at the three categories above, after 2 h, 1 d, 2 d, 3 d and 7 d. Regarding the exposure period, at 1000 ppm, all adults of the susceptible strain were immobilized after 60 min of exposure, and remained at this condition until the end of the observation period. At the same concentration, the majority of adults of the resistant strain remained active until the end of the observation period. At 3000 ppm, for the susceptible strain, all adults became immobilized after 90 min observation. For the same concentration, the percentage of the adults of the resistant strain that were active was notably reduced in comparison with 1000 ppm. For the post-exposure period, at 1000 or 3000 ppm, for the susceptible strain, the number of adults that were immobilized reached 95 % after 7 d. At the same phosphine concentration, almost all of the adults of the resistant strain were active even at the 2 h post-exposure period, and practically remain at this condition until the end of the observation period. Our findings indicate that time-to-narcosis / immobilization is inversely proportional to time-to-recovery of the same individuals, and this characteristic can be also considered as an indicator for resistance
Evaluation of aflatoxin contamination of stored maize in the Brong-Ahafo region of Ghana: Poster
Get PDFThis study assessed the aflatoxin contamination and the presence of fungi in three maize varieties (Obatanpa, Abontem and Aburohemaa) stored using different storage methods namely storage in hermetic bags, woven polypropylene sacks and local crib in the Nkoranza-South district of the Brong-Ahafo region of Ghana. A factorial design arrangement was laid out in a randomized complete block design (RCBD). The isolation and identification of fungal pathogens associated with maize samples before and after storage were carried out on potato dextrose agar (PDA). Total flatoxin levels in the three maize varieties was determined by the use of enzyme-linked immunosorbent assay (ELISA) at 450 nm wavelength. Six fungi species were identified in the maize namely: Aspergillus flavus, Penicillium sp, Fusarium sp., Lasiodiplodia theobromae, Colletotrichum gleosporioides and Rhizopus. Before storage, Abontem variety recorded significantly higher (p < 0.05) total aflatoxin levels (113.56 ppb) compared to Obatanpa (2.91 ppb) and Aburohemaa (2.96 ppb). Maize samples stored in the polypropylene sack established significantly higher (p < 0.05) total aflatoxin levels of 82.9 ppb compared to hermetic bags (48.9 ppb) and local crib (48.9 ppb) after storage for six months. Aflatoxin levels under the interactive effect of variety and storage method was significant (p < 0.05). Overall storage of maize in hermetic bags significantly reduced aflatoxin levels hence the need to encourage maize farmers and traders to adopt hermetic bag storage technology.This study assessed the aflatoxin contamination and the presence of fungi in three maize varieties (Obatanpa, Abontem and Aburohemaa) stored using different storage methods namely storage in hermetic bags, woven polypropylene sacks and local crib in the Nkoranza-South district of the Brong-Ahafo region of Ghana. A factorial design arrangement was laid out in a randomized complete block design (RCBD). The isolation and identification of fungal pathogens associated with maize samples before and after storage were carried out on potato dextrose agar (PDA). Total flatoxin levels in the three maize varieties was determined by the use of enzyme-linked immunosorbent assay (ELISA) at 450 nm wavelength. Six fungi species were identified in the maize namely: Aspergillus flavus, Penicillium sp, Fusarium sp., Lasiodiplodia theobromae, Colletotrichum gleosporioides and Rhizopus. Before storage, Abontem variety recorded significantly higher (p < 0.05) total aflatoxin levels (113.56 ppb) compared to Obatanpa (2.91 ppb) and Aburohemaa (2.96 ppb). Maize samples stored in the polypropylene sack established significantly higher (p < 0.05) total aflatoxin levels of 82.9 ppb compared to hermetic bags (48.9 ppb) and local crib (48.9 ppb) after storage for six months. Aflatoxin levels under the interactive effect of variety and storage method was significant (p < 0.05). Overall storage of maize in hermetic bags significantly reduced aflatoxin levels hence the need to encourage maize farmers and traders to adopt hermetic bag storage technology