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Daphne Mahon - One of the best experts on this subject based on the ideXlab platform.
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evaluation of microwave irradiation for analysis of carbonyl sulfide carbon disulfide cyanogen ethyl formate methyl bromide Sulfuryl Fluoride propylene oxide and phosphine in hay
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Daphne MahonAbstract:Fumigant residues in hay were “extracted” by microwave irradiation. Hay, in gastight glass flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for carbonyl sulfide (COS), carbon disulfide (CS2), cyanogen (C2N2), ethyl formate (EF), methyl bromide (CH3Br), Sulfuryl Fluoride (SF), propylene oxide (PPO), and phosphine (PH3). Recoveries of fortified samples were >91% for COS, CS2, CH3Br, SF, PPO, and PH3 and >76% for C2N2 and EF. Completeness of extraction was assessed from the amount of fumigant retained by the microwaved hay. This amount was determined from further microwave irradiation and was always small (<5% of the amount obtained from the initial procedure). Limits of quantification were <0.1 mg/kg for COS, CS2, C2N2, EF, and PH3 and <0.5 mg/kg for CH3Br, SF, and PPO. These low limits were essentially due to the absence of interference from solvents and no necessity to i...
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evaluation of microwave irradiation for analysis of carbonyl sulfide carbon disulfide cyanogen ethyl formate methyl bromide Sulfuryl Fluoride propylene oxide and phosphine in hay
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Yonglin Ren, Daphne MahonAbstract:Fumigant residues in hay were "extracted" by microwave irradiation. Hay, in gastight glass flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for carbonyl sulfide (COS), carbon disulfide (CS(2)), cyanogen (C(2)N(2)), ethyl formate (EF), methyl bromide (CH(3)Br), Sulfuryl Fluoride (SF), propylene oxide (PPO), and phosphine (PH(3)). Recoveries of fortified samples were >91% for COS, CS(2), CH(3)Br, SF, PPO, and PH(3) and >76% for C(2)N(2) and EF. Completeness of extraction was assessed from the amount of fumigant retained by the microwaved hay. This amount was determined from further microwave irradiation and was always small (<5% of the amount obtained from the initial procedure). Limits of quantification were <0.1 mg/kg for COS, CS(2), C(2)N(2), EF, and PH(3) and <0.5 mg/kg for CH(3)Br, SF, and PPO. These low limits were essentially due to the absence of interference from solvents and no necessity to inject large-volume gas samples. The microwave method is rapid and solvent-free. However, care is required in selecting the appropriate power setting. The safety implications of heating sealed flasks in microwave ovens should be noted.
Glenn M. Sammis - One of the best experts on this subject based on the ideXlab platform.
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halide accelerated acyl Fluoride formation using Sulfuryl Fluoride
Organic Letters, 2020Co-Authors: Paul J. Foth, Jason E. Hein, Thomas C Malig, Trevor G Bolduc, Glenn M. SammisAbstract:Herein, we report a new one-pot sequential method for SO2F2-mediated nucleophilic acyl substitution reactions starting from carboxylic acids. A mechanistic study revealed that SO2F2-mediated acid a...
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one pot substitution of aliphatic alcohols mediated by Sulfuryl Fluoride
Chemistry: A European Journal, 2020Co-Authors: Maxim Epifanov, Jack Hodgson, Rudy Dubois, Glenn M. SammisAbstract:The Mitsunobu reaction is a powerful transformation for the one-pot activation and substitution of aliphatic alcohols. Significant efforts have focused on modifying the classic conditions to overcome problems associated with purification from phosphine-based byproducts. Herein, we report a phosphine free method for alcohol activation and substitution that is mediated by Sulfuryl Fluoride. This new method is effective for a wide range of primary alcohols using phthalimide, di-tert-butyl-iminodicarboxylate, and aromatic thiol nucleophiles in 74 % average yield. Activated carbon nucleophiles and a deactivated phenol were also effective for this reaction in good yields. Secondary alcohols were also successful substrates using aryl thiols, affording the corresponding sulfides in 56 % average yield with enantiomeric ratios up to 99:1. This new protocol has a distinct synthetic advantage over many existing phosphine-based methods as the byproducts are readily separable. This feature was exploited in several examples that did not require chromatography for purification. Furthermore, the mild reaction conditions enabled further in situ derivatization for the one-pot conversion of alcohols to amines or sulfones. This method also provides a boarder nucleophile scope compared to existing phosphine-free methods.
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one pot fluoroSulfurylation of grignard reagents using Sulfuryl Fluoride
Chemical Communications, 2019Co-Authors: Cayo Lee, Nicholas D Ball, Glenn M. SammisAbstract:Herein, we report a new method for the one-pot syntheses of sulfonyl Fluorides. Addition of an alkyl, aryl, or heteroaryl Grignard to a solution of Sulfuryl Fluoride at ambient temperature affords the desired sulfonyl Fluorides in 18–78% yield. Furthermore, this method is applicable for in situ sequential reactions, whereby the Grignard reagent can be converted to the corresponding diarylsulfone, sulfonate ester, or sulfonamide in a one-pot process.
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new Sulfuryl Fluoride derived alkylating reagents for the 1 1 dihydrofluoroalkylation of thiols
Chemical Science, 2019Co-Authors: Paul J. Foth, Sahil S. Kanani, Trevor G Bolduc, Glenn M. SammisAbstract:Herein, we report a new method for the one-pot synthesis of 1,1-dihydrofluoroalkyl sulfides by bubbling Sulfuryl Fluoride (SO2F2) through a solution of the corresponding alcohol and thiol. The reaction proceeds through a new class of bis(1,1-dihydrofluoroalkyl) sulfate reagents, to afford the desired 1,1-dihydrofluoroalkyl sulfides in 55–90% isolated yields. The bis(1,1-dihydrofluoroalkyl) sulfates are highly chemoselective for thiol alkylation, and are unreactive with competing, unprotected nucleophiles, including amines, alcohols, and carboxylic acids.
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One-Pot 1,1-Dihydrofluoroalkylation of Amines Using Sulfuryl Fluoride
2018Co-Authors: Maxim Epifanov, Paul J. Foth, Charlotte Barrillon, Sahil S. Kanani, Carolyn S Higman, Jason E. Hein, Glenn M. SammisAbstract:Sulfuryl Fluoride, SO2F2, has been known and used as a fumigant for over 50 years but it has only recently gained widespread interest as a reagent for organic synthesis. Herein we report a novel application of Sulfuryl Fluoride gas in a new 1,1-dihydrofluoroalkylation reaction, which simply involves bubbling SO2F2 through a solution of amine, 1,1-dihydrofluoroalcohol, and diisopropylethylamine. The reaction is successful for a wide range of primary and secondary amines, as well as several 1,1-dihydrofluoroalcohols, to afford the 1,1-dihydrofluoroalkylated amines in 42% to 80% isolated yields. The reaction also displays excellent functional group tolerance. The ease of the one-pot activation and alkylation, combined with the wide substrate scope make this new procedure an attractive alternative to existing 1,1-dihydrofluoroalkylation methodologies
Manoj K. Nayak - One of the best experts on this subject based on the ideXlab platform.
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Co-fumigation with phosphine and Sulfuryl Fluoride: Potential for managing strongly phosphine-resistant rusty grain beetle, Cryptolestes ferrugineus (Stephens):
Julius-Kühn-Archiv, 2018Co-Authors: Jagadeesan Rajeswaran, Manoj K. Nayak, Virgine T Singarayan, Paul R. EbertAbstract:Populations of rusty grain beetle, Cryptolestes ferrugineus, have developed a very high level of resistance (1300×) to the fumigant phosphine (PH3) in Australia. Resistant insects triggered control failures, threatening the country’s annual grain market worth AU$8 billion. Although PH3 protocols were amended to manage this new resistance, fumigation requires lengthy exposure periods which has practical difficulties. While there is no suitable replacement for PH3, the current study explores potential approaches to enhance the efficacy of this fumigant. One possibility is co-fumigation of PH3 with another complementary fumigant, Sulfuryl Fluoride (SO2F2 or SF), with the dual goals: enhanced efficacy and minimise use of both fumigants. A cohort of mixed age eggs and adults of PH3-resistant C. ferrugineus was fumigated with PH3 and SF individually, as well as in combination inside desiccators at 25°C and 60%RH for 168 h. Two doses below the maximal registered rates for SF (8.9 mg L- 1, equivalent to 1500 g hm-3) and PH3 (1.0 mg L-1) were tested. Co-fumigation was performed simultaneously for 168 h. Our results revealed that, the mixture of 1.1 mg L-1 or 2.2 mg L-1 of SF and 0.5 mg L-1 of PH3 over 168 h achieved complete control against resistant C. ferrugineus eggs and adults, whereas each of the tested doses failed individually. Our study confirms that SF and PH3 enhance the efficacy of each other when used in combination, which holds great potential for managing resistant C. ferrugineus.
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Integrated approach to manage strong resistance to phosphine (PH3) in rusty grain beetle, Cryptolestes ferrugineus
2017Co-Authors: Rajeswaran Jagadeesan, Gregory J. Daglish, Hervoika Pavic, Paul R. Ebert, Manoj K. NayakAbstract:Populations of rusty grain beetle, Cryptolestes ferrugineus, a cosmopolitan grain insect pest, have recently developed a very high-level of resistance (1300×) to fumigant phosphine in Australia, threatening the country’s international grain market worth of 8 billion per year. Due to the failure of the registered rates of phosphine, industry urgently needed alternative strategies to manage this new resistance. To address this, an integrated resistance management strategy (IRM) was developed with three core components: 1. regular monitoring and characterization of resistance, 2. developing effective phosphine protocols, and 3. exploring alternative fumigants and treatments. Resistance was monitored across Australia in pest samples collected from farms and centrals storages using a modified FAO method as well as quick knockdown tests. Our results indicated that high-level resistance in C. ferrugineus is prevalent in eastern Australia, particularly in Queensland and New South Wales, particularly in the bulk handing sector. Time to population extinction was assessed in field-derived reference resistant strains using higher dosages (c) and exposure times (t) and the effective c x t regimes were validated in the field for the use by the grain industry. A phosphine concentration of 720 ppm (1 mg L-1) over 18 days was found to be effective in controlling all life stages of phosphine-resistant C. ferrugineus at 25°C. In a parallel research, the suitability of Sulfuryl Fluoride (ProfumeTM), as an alternative fumigant to phosphine was assessed through laboratory and field efficacy trials. Our results showed that phosphine-resistant insects are highly susceptible to Sulfuryl Fluoride and a CT of 750 g hm-3 (5.2 mg L-1) over 6 days at 25˚C would be sufficient against all phosphine-resistant pests including C. ferrugineus. While Sulfuryl Fluoride has promising potential as a “phosphine resistance breaker” the team is currently exploring ways of co-treating phosphine and Sulfuryl Fluoride, in order to reduce the overall selection pressure against these two fumigants in insects.
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susceptibility to Sulfuryl Fluoride and lack of cross resistance to phosphine in developmental stages of the red flour beetle tribolium castaneum coleoptera tenebrionidae
Pest Management Science, 2015Co-Authors: Rajeswaran Jagadeesan, Manoj K. Nayak, Hervoika Pavic, Kerri Chandra, Patrick J CollinsAbstract:BACKGROUND Our aim was to ascertain the potential of Sulfuryl Fluoride (SF) as an alternative fumigant to manage phosphine-resistant pests. We tested the susceptibility of all life stages of red flour beetle, Tribolium castaneum (Herbst), to SF and assessed the presence of cross-resistance to this fumigant in phosphine-resistant strains of this species. RESULTS Analysis of dose–response data indicated that the egg was the stage most tolerant to SF under a 48 h exposure period. At LC50, eggs were 29 times more tolerant than other immature stages and adults, and required a relatively high concentration of 48.2 mg L−1 for complete mortality. No significant differences in tolerance to SF were observed among the three larval instars, pupae and adults, and all of these stages were controlled at a low concentration of 1.32 mg L−1. Phosphine-resistant strains did not show cross-resistance to SF. CONCLUSION Our research concluded that the current maximum registered rate of SF, 1500 gh m−3, is adequate to control all the post-embryonic life stages of T. castaneum over a 48 h fumigation period, but it will fail to achieve complete mortality of eggs, indicating the risk of some survival of eggs under this short exposure period. As there is no cross-resistance to SF in phosphine-resistant insects, it will play a key role in managing phosphine resistance in stored-grain insect pests. © 2014 Commonwealth of Australia. Pest Management Science © 2014 Society of Chemical Industry
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sorption and desorption of Sulfuryl Fluoride by wheat flour and semolina
Journal of Stored Products Research, 2015Co-Authors: Mudhir I Hwaidi, Hervoika Pavic, Patrick J Collins, Mike Sissons, Manoj K. NayakAbstract:Abstract Sulfuryl Fluoride (SF) has been developed as a fumigant for control of insect pests in stored grain. However, there is very limited information on the sorption behaviour of this fumigant, which can be critical to its bioactivity, application and potential for residues. We undertook a comprehensive laboratory study of the sorption and desorption of SF by wheat (bread and durum), flour and semolina at 15, 25 and 35 °C, moisture contents 12% and 15%, and concentration × time combinations at CT = 1500 mgh/L (4.167 mg/L × 360 h, 8.928 mg/L × 168 h and 31.25 mg/L × 48 h). At each dosage, sorption rate increased as commodity temperature and moisture content increased. The highest rates of sorption occurred at 35 °C and 15% m.c., and lowest rates at 15 °C and 12% m.c., and the rate was independent of initial concentration. Sorption followed first order reaction kinetics described by the exponential decay equation, Ct = C0·e−k*t, where k is the sorption rate constant. The most important factors determining the rate of sorption were commodity particle size (exposed surfaces) and temperature. Little sorption of fumigant occurred within the first 24 h whereas longer fumigation times resulted in significant sorption. Unbound SF was rapidly lost from the commodity upon aeration with no further desorption detected under any of the test conditions. SF possesses a number of characteristics that recommend it as a commodity fumigant. It is sorbed slowly by commodities relative to methyl bromide and carbonyl sulphide although it is sorbed about 4–5 times faster than phosphine. It desorbs rapidly upon aeration, and the lack of continued desorption has practical workplace health and safety benefits. On the other hand, sorbed SF appears irreversibly bound to the commodity matrix indicating the need to be alert to the possibility of excessive residues, particularly in longer term fumigations.
Rajeswaran Jagadeesan - One of the best experts on this subject based on the ideXlab platform.
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Integrated approach to manage strong resistance to phosphine (PH3) in rusty grain beetle, Cryptolestes ferrugineus
2017Co-Authors: Rajeswaran Jagadeesan, Gregory J. Daglish, Hervoika Pavic, Paul R. Ebert, Manoj K. NayakAbstract:Populations of rusty grain beetle, Cryptolestes ferrugineus, a cosmopolitan grain insect pest, have recently developed a very high-level of resistance (1300×) to fumigant phosphine in Australia, threatening the country’s international grain market worth of 8 billion per year. Due to the failure of the registered rates of phosphine, industry urgently needed alternative strategies to manage this new resistance. To address this, an integrated resistance management strategy (IRM) was developed with three core components: 1. regular monitoring and characterization of resistance, 2. developing effective phosphine protocols, and 3. exploring alternative fumigants and treatments. Resistance was monitored across Australia in pest samples collected from farms and centrals storages using a modified FAO method as well as quick knockdown tests. Our results indicated that high-level resistance in C. ferrugineus is prevalent in eastern Australia, particularly in Queensland and New South Wales, particularly in the bulk handing sector. Time to population extinction was assessed in field-derived reference resistant strains using higher dosages (c) and exposure times (t) and the effective c x t regimes were validated in the field for the use by the grain industry. A phosphine concentration of 720 ppm (1 mg L-1) over 18 days was found to be effective in controlling all life stages of phosphine-resistant C. ferrugineus at 25°C. In a parallel research, the suitability of Sulfuryl Fluoride (ProfumeTM), as an alternative fumigant to phosphine was assessed through laboratory and field efficacy trials. Our results showed that phosphine-resistant insects are highly susceptible to Sulfuryl Fluoride and a CT of 750 g hm-3 (5.2 mg L-1) over 6 days at 25˚C would be sufficient against all phosphine-resistant pests including C. ferrugineus. While Sulfuryl Fluoride has promising potential as a “phosphine resistance breaker” the team is currently exploring ways of co-treating phosphine and Sulfuryl Fluoride, in order to reduce the overall selection pressure against these two fumigants in insects.
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susceptibility to Sulfuryl Fluoride and lack of cross resistance to phosphine in developmental stages of the red flour beetle tribolium castaneum coleoptera tenebrionidae
Pest Management Science, 2015Co-Authors: Rajeswaran Jagadeesan, Manoj K. Nayak, Hervoika Pavic, Kerri Chandra, Patrick J CollinsAbstract:BACKGROUND Our aim was to ascertain the potential of Sulfuryl Fluoride (SF) as an alternative fumigant to manage phosphine-resistant pests. We tested the susceptibility of all life stages of red flour beetle, Tribolium castaneum (Herbst), to SF and assessed the presence of cross-resistance to this fumigant in phosphine-resistant strains of this species. RESULTS Analysis of dose–response data indicated that the egg was the stage most tolerant to SF under a 48 h exposure period. At LC50, eggs were 29 times more tolerant than other immature stages and adults, and required a relatively high concentration of 48.2 mg L−1 for complete mortality. No significant differences in tolerance to SF were observed among the three larval instars, pupae and adults, and all of these stages were controlled at a low concentration of 1.32 mg L−1. Phosphine-resistant strains did not show cross-resistance to SF. CONCLUSION Our research concluded that the current maximum registered rate of SF, 1500 gh m−3, is adequate to control all the post-embryonic life stages of T. castaneum over a 48 h fumigation period, but it will fail to achieve complete mortality of eggs, indicating the risk of some survival of eggs under this short exposure period. As there is no cross-resistance to SF in phosphine-resistant insects, it will play a key role in managing phosphine resistance in stored-grain insect pests. © 2014 Commonwealth of Australia. Pest Management Science © 2014 Society of Chemical Industry
Jagadeesan Rajeswaran - One of the best experts on this subject based on the ideXlab platform.
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A co-fumigation strategy utilizing reduced rates of phosphine (PH3) and Sulfuryl Fluoride (SF) to control strongly resistant rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae)
'Wiley', 2021Co-Authors: Jagadeesan Rajeswaran, Singarayan, Virgine T, Nayak, Manoj K.Abstract:BACKGROUND Managing resistance to phosphine (PH3) in rusty grain beetle, Cryptolestes ferrugineus, is challenging, as strongly resistant insects of this species require very high concentrations over lengthy exposure periods (>10 days). Recently, approaches that enhance the efficacy of PH3 have gained momentum to control this pest, especially co-fumigations. In this study, efficacy of co-fumigating PH3 with another commercially available fumigant, Sulfuryl Fluoride (SF), has been evaluated against adults and eggs of two PH3-resistant strains of C. ferrugineus. Concentrations of the mixture, representing lower than current application rates of both fumigants, were tested towards its field use. RESULTS Co-fumigation of PH3 with SF was achieved in two patterns: over a continuous exposure period of 168 h simultaneously and sequentially over two periods of 78 h, in which insects were exposed to SF first followed by PH3 with 12 h aeration in-between. Results of simultaneous fumigations identified two effective co-fumigation rates, SF 185 + PH3 168 g hm−3 and SF 370 + PH3 84 g hm−3 that yielded complete control of adults and eggs. These two rates also were equally effective when they were applied sequentially and produced consistent results. Irrespective of application methods, concentrations of both PH3 and SF failed individually in achieving complete mortality of either adults or eggs or both. CONCLUSION Our results confirmed that a co-fumigation strategy involving half the current standard rate of PH3 (84 g hm−3) with one-fourth of the current maximal registered rate of SF (370 g hm−3) can provide effective control of strongly PH3-resistant C. ferrugineus
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Co-fumigation with phosphine and Sulfuryl Fluoride: Potential for managing strongly phosphine-resistant rusty grain beetle, Cryptolestes ferrugineus (Stephens):
Julius-Kühn-Archiv, 2018Co-Authors: Jagadeesan Rajeswaran, Manoj K. Nayak, Virgine T Singarayan, Paul R. EbertAbstract:Populations of rusty grain beetle, Cryptolestes ferrugineus, have developed a very high level of resistance (1300×) to the fumigant phosphine (PH3) in Australia. Resistant insects triggered control failures, threatening the country’s annual grain market worth AU$8 billion. Although PH3 protocols were amended to manage this new resistance, fumigation requires lengthy exposure periods which has practical difficulties. While there is no suitable replacement for PH3, the current study explores potential approaches to enhance the efficacy of this fumigant. One possibility is co-fumigation of PH3 with another complementary fumigant, Sulfuryl Fluoride (SO2F2 or SF), with the dual goals: enhanced efficacy and minimise use of both fumigants. A cohort of mixed age eggs and adults of PH3-resistant C. ferrugineus was fumigated with PH3 and SF individually, as well as in combination inside desiccators at 25°C and 60%RH for 168 h. Two doses below the maximal registered rates for SF (8.9 mg L- 1, equivalent to 1500 g hm-3) and PH3 (1.0 mg L-1) were tested. Co-fumigation was performed simultaneously for 168 h. Our results revealed that, the mixture of 1.1 mg L-1 or 2.2 mg L-1 of SF and 0.5 mg L-1 of PH3 over 168 h achieved complete control against resistant C. ferrugineus eggs and adults, whereas each of the tested doses failed individually. Our study confirms that SF and PH3 enhance the efficacy of each other when used in combination, which holds great potential for managing resistant C. ferrugineus.
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Co-fumigation with phosphine and Sulfuryl Fluoride: Potential for managing strongly phosphine-resistant rusty grain beetle, Cryptolestes ferrugineus (Stephens): Presentation
Julius-Kühn-Archiv, 2018Co-Authors: Jagadeesan Rajeswaran, Nayak, Manoj K., Singarayan Virgine, Ebert, Paul R.Abstract:Populations of rusty grain beetle, Cryptolestes ferrugineus, have developed a very high level of resistance (1300×) to the fumigant phosphine (PH3) in Australia. Resistant insects triggered control failures, threatening the country’s annual grain market worth AU$8 billion. Although PH3 protocols were amended to manage this new resistance, fumigation requires lengthy exposure periods which has practical difficulties. While there is no suitable replacement for PH3, the current study explores potential approaches to enhance the efficacy of this fumigant. One possibility is co-fumigation of PH3 with another complementary fumigant, Sulfuryl Fluoride (SO2F2 or SF), with the dual goals: enhanced efficacy and minimise use of both fumigants. A cohort of mixed age eggs and adults of PH3-resistant C. ferrugineus was fumigated with PH3 and SF individually, as well as in combination inside desiccators at 25°C and 60%RH for 168 h. Two doses below the maximal registered rates for SF (8.9 mg L- 1, equivalent to 1500 g hm-3) and PH3 (1.0 mg L-1) were tested. Co-fumigation was performed simultaneously for 168 h. Our results revealed that, the mixture of 1.1 mg L-1 or 2.2 mg L-1 of SF and 0.5 mg L-1 of PH3 over 168 h achieved complete control against resistant C. ferrugineus eggs and adults, whereas each of the tested doses failed individually. Our study confirms that SF and PH3 enhance the efficacy of each other when used in combination, which holds great potential for managing resistant C. ferrugineus.Populations of rusty grain beetle, Cryptolestes ferrugineus, have developed a very high level of resistance (1300×) to the fumigant phosphine (PH3) in Australia. Resistant insects triggered control failures, threatening the country’s annual grain market worth AU$8 billion. Although PH3 protocols were amended to manage this new resistance, fumigation requires lengthy exposure periods which has practical difficulties. While there is no suitable replacement for PH3, the current study explores potential approaches to enhance the efficacy of this fumigant. One possibility is co-fumigation of PH3 with another complementary fumigant, Sulfuryl Fluoride (SO2F2 or SF), with the dual goals: enhanced efficacy and minimise use of both fumigants. A cohort of mixed age eggs and adults of PH3-resistant C. ferrugineus was fumigated with PH3 and SF individually, as well as in combination inside desiccators at 25°C and 60%RH for 168 h. Two doses below the maximal registered rates for SF (8.9 mg L- 1, equivalent to 1500 g hm-3) and PH3 (1.0 mg L-1) were tested. Co-fumigation was performed simultaneously for 168 h. Our results revealed that, the mixture of 1.1 mg L-1 or 2.2 mg L-1 of SF and 0.5 mg L-1 of PH3 over 168 h achieved complete control against resistant C. ferrugineus eggs and adults, whereas each of the tested doses failed individually. Our study confirms that SF and PH3 enhance the efficacy of each other when used in combination, which holds great potential for managing resistant C. ferrugineus
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Potential of co-fumigation with phosphine (PH3) and Sulfuryl Fluoride (SO2F2) for the management of strongly phosphine-resistant insect pests of stored grain
'Oxford University Press (OUP)', 2018Co-Authors: Jagadeesan Rajeswaran, Ebert, Paul R., Singarayan, Virgine T, Chandra Kerri, Nayak, Manoj K.Abstract:Resistance to phosphine (PH3) in key insect pests of stored grain is increasing, with a requirement for maintaining a dose as high as 1 mg l-1 for 14 d for effective fumigation, which is difficult to achieve under most commercial storage conditions. There is no suitable replacement for PH3, as most of the available alternatives suffer from specific weaknesses, creating an urgent need to increase the efficacy of this fumigant. One such possibility is co-fumigation of PH3 with another fumigant, Sulfuryl Fluoride (SO2F2-SF), with the goal of decreasing the time required for a successful fumigation. In this study, adult of two PH3-resistant strains in each of four key grain insect pests, Rhyzopertha dominica, (F.) (Coleoptera: Bostrichidae) Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), Sitophilus oryzae (L.) (Coleoptera: Curculionidae), and Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) were fumigated with PH3 and SF individually as well as in combinations at 25°C over 48 h. Mortality responses in each species were subjected to probit analysis to determine the LC50 and LC99.9 of PH3, SF, and PH3 + SF. Co-fumigation of PH3 with SF resulted in a 50% reduction of the PH3 concentration required to achieve 99.9% mortality in two pest species. For example, the PH3 + SF mixture, reduced the amount of PH3 required from 14.2-14.5 to 5.6-6.36 mg l-1 and from 2.71-5.03 to 0.93-1.2 mg l-1, respectively, for C. ferrugineus and S. oryzae. The overall mortality response to the PH3 + SF mixture followed an "additive model" suggesting that mutual enhancement in toxicity can be achieved with this mixture specifically to control PH3-resistant insects
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Co-fumigation with phosphine (PH3) and Sulfuryl Fluoride (SO2F2) for the management of strongly phosphine-resistant insect pests of stored grain
'Entomological Society of America', 2016Co-Authors: Jagadeesan Rajeswaran, Nayak Manoj, Pavic Hervoika, Singarayan Virginetenshia, Ebert, Paul R.Abstract:Introduction: Phosphine (PH3), an effective fumigant used to protect stored grains from insect pests. As resistance to PH3 is widespread, effective fumigation requires lengthy exposure periods (>7 days) which has practical difficulties. There is an urgent need to develop alternative approaches that can increase the efficacy of PH3. One possibility is co-fumigation with PH3 and another fumigant such as Sulfuryl-Fluoride (SO2F2), which has properties complementary to PH3. Here we present the results of PH3+SO2F2co-fumigation of key stored grain insect pests. Methodology: Adult beetles were fumigated with PH3 and SO2F2individually as well as in combination inside air-tight desiccators at 25°C and 65% RH for 48 hours. Mortality after a recovery period of 14 days was recorded and the data was subjected to probit analysis. Experiments were replicated twice. Results: Comparison of estimated effective doses (LC99.9) of PH3, SO2F2 and PH3+SO2F2 for each of the four PH3-resistant grain insect species, Tribolium castaneum, Cryptolestes ferrugineus, Sitophilus oryzae and Rhyzopertha dominca indicated that co-fumigation with SO2F2 at half of its effective dose (0.22-0.82 mg L-1) reduced the amount of PH3 required to one third (0.33 to 5.8 mg L-1). There was no interaction between resistance to PH3 and sensitivity to SO2F2.The analysis on observed and expected mortality response curves of PH3+SO2F2in all the four species confirmed that the interaction was additive. Conclusion: SO2F2 enhances the toxicity of PH3 in an “additive” manner in PH3-resistant insect species, thus treating PH3 jointly with SO2F2 holds great potentials for pest and resistance management
