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1.
Five species of stored-product insects, [Tribolium castaneum (Herbst), T. confusum (DuVal), Rhyzopertha dominica (F.), Sitophilus oryzae (L.) and S. granarius (L.)], exposed to phosphine in nitrogen and various oxygen-deficient atmospheres, showed reduced susceptibility to three concentrations of phosphine (0.02, 0.04 and 0.2 mg litre?1). The last two species also showed reduced susceptibility to phosphine at 2.0 mg litre?1. Generally mortality increased progressively as the level of oxygen was raised. There was a close relationship between the ability of insects to withstand anoxia and survival from phosphine treatment.  相似文献   

2.
Duplicate field trials were carried out on bulk wheat in commercial silos in Queensland and New South Wales. Laboratory bioassays on samples of treated grain at intervals over 9 months, using malathion-resistant strains of insects, established that treatments were generally effective. Fenitrothion (12 mg kg?1)+ (1R)-phenothrin (2 mg kg?1) was more effective than pirimiphos-methyl (6 mg kg?1) + carbaryl (10 mg kg?1) against Sitophilus oryzae (L.) and Ephestia cautella (Walker); the order of effectiveness was reversed for S. granarius (L.). Against Rhyzopertha dominica (F.), Tribolium castaneum (Herbst), T. confusum Jackquelin du Val and Oryzaephilus surinamensis (L.), both treatments effectively prevented the production of progeny. The order of persistence was pirimiphos-methyl> (1R)-phenothrin>carbaryl or fenitrothion. During processing from wheat to white bread, residues were reduced by 98% for carbaryl, >44% for (1R)-phenothrin, 98% for fenitrothion and 85% for pirimiphosmethyl.  相似文献   

3.
BACKROUND: Fipronil is an insecticidal pyrazole that is commonly used as an insecticide in field crops, urban pesticide and veterinary medicine, but there are no reports of its evaluation against stored‐product insects. Three series of laboratory bioassays were conducted to assess fipronil as a potential grain protectant against adults of Sitophilus oryzae (L.), Tribolium confusum Jacquelin du Val, Rhyzopertha dominica (F.) and Prostephanus truncatus (Horn). Factors such as dose (0.01, 0.1, 1 and 10 mg fipronil kg?1 grain), exposure interval (24 h, 48 h, 7 days and 14 days), temperature (20, 25 and 30 °C), relative humidity (RH; 55 and 65%) and commodity (wheat, maize, barley and paddy rice) were evaluated with regard to their impact on the insecticidal activity of fipronil. Progeny production was assessed after 64 days of exposure. RESULTS: At doses of < 1 mg fipronil kg?1 grain, efficacy of fipronil was enhanced by an increase in temperature from 20 to 25 °C against S. oryzae or R. dominica for exposures of > 48 h and against T. confusum or P. truncatus for exposures of > 24 h. A further increase in temperature from 25 to 30 °C, although it enhanced efficacy at doses of < 1 mg fipronil kg?1 grain against S. oryzae at all exposure intervals and against T. confusum after 7 days of exposure, it was negatively associated with efficacy against R. dominica or P. truncatus for exposures of > 24 h. By contrast, increase in RH did not have a significant impact on efficacy of fipronil. Although the performance of fipronil among the tested commodities was species dependent, this substance appeared to be less effective in paddy rice than in barley, maize and wheat. Regardless of the treated commodity, progeny production of all the tested species was almost suppressed with doses higher than 0.1 mg fipronil kg?1 grain. CONCLUSIONS: Fipronil appeared to be a very effective alternative to the existing substances in stored‐grain protection at doses equal to or higher than 1 mg fipronil kg?1 grain, and thus these doses require further evaluation in terms of safety for the consumer and residues on stored products. Copyright © 2010 Society of Chemical Industry  相似文献   

4.
Field trials with various pesticide combinations were carried out on bulk wheat in commercial silos in Queensland, South Australia and Western Australia. Laboratory bioassays on samples of treated grain at intervals over 8 months using malathion-susceptible and malathion-resistant strains established the following orders of efficacy: against Sitophilus oryzae (L.), chlorpyrifos-methyl 10 mg kg?1 + bioresmethrin 1 mg kg?1 = methacrifos 15 mg kg?1 in aerated storage > pirimiphos-methyl 4 or 6 mg kg?1 + bioresmethrin 1 mg kg?1 = bioresmethrin 4 mg kg?1 + piperonyl butoxide 16 mg kg?1; against Rhyzopertha dominica (F.), bioresmethrin 4 mg kg?1 + piperonyl butoxide 16 mg kg?1 > methacrifos 15 mg kg?1 > chlorpyrifos-methyl 10 mg kg?1 + bioresmethrin 1 mg kg?1 = pirimiphos-methyl 4 or 6 mg kg?1 + bioresmethrin 1 mg kg?1. All treatments completely prevented production of progeny in Sitophilus granarius (L.), Tribolium castaneum (Herbst), T. confusum Jackquelin du Val and Oryzaephilus surinamensis (L.). The biological efficacy of methacrifos was greater and the rate of degradation lower in aerated than in non-aerated storage. Residue levels of all compounds were determined chemically and were below proposed international residue levels to be considered by the Codex Alimentarius Commission.  相似文献   

5.
BACKGROUND: The ethyl formate/carbon dioxide (CO2) formulation Vapormate? is a rapid‐acting fumigant being developed for the control of stored‐grain insects. The effects have been investigated of concentration, exposure times of 1, 3, 24 and 72 h and two grain temperatures, 15 and 25 °C, on its efficacy against mixed‐stage cultures of Sitophilus oryzae (L.) Tribolium castaneum (Herbst) and strongly phosphine‐resistant Rhyzopertha dominica (F.) strain QRD569. RESULTS: High mortalities (≥92%) of mixed‐stage cultures of all three species were obtained when grain was fumigated with the formulation (193 g m?3 ethyl formate) for 1 h. Complete control of R. dominica QRD569 and T. castaneum was achieved with 63 and 76 g m?3 ethyl formate respectively, with exposure for 24 h, whereas mean mortality of S. oryzae was 86% under the same conditions. Mortalities of S. oryzae juvenile stages were significantly lower than adults under the conditions tested, which was due to pronounced tolerance of mid‐stage pupae to the fumigant. Reducing grain temperature from 25 to 15 °C had no effect on insect mortality. CONCLUSION: Ethyl formate/CO2 formulation is highly effective against stored‐grain insects over a range of concentrations and exposure times. Efficacious fumigations were conducted in as little as 1 h, and a strongly phosphine‐resistant R. dominica strain was readily controlled with the fumigant. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd  相似文献   

6.
Organophosphorothioates and synergised synthetic pyrethroids were used in duplicate field trials carried out on bulk wheat in commercial silos in Queensland and New South Wales. Laboratory bioassays using malathion-resistant strains of insects were carried out on samples of treated grain at intervals over 9 months. These established that all treatments were generally effective. Deltamethrin (2 mg kg?1)+ piperonyl butoxide (8 mg kg?1), fenitrothion (12 mg kg?1)+ fenvalerate (1 mg kg?1)+ piperonyl butoxide (8 mg kg?1), fenitrothion (12 mg kg?1)+ phenothrin (2 mg kg?1)+ piperonyl butoxide (8 mg kg?1) and pirimiphos-methyl (4 mg kg?1)+ permethrin (1 mg kg?1)+ piperonyl butoxide (8 mg kg?1) controlled common field strains of Sitophilus oryzae (L.) and Rhyzopertha dominica (F.). Against a highly resistant strain of S. oryzae, deltamethrin (2 mg kg?1)+ piperonyl butoxide (8 mg kg?1) was superior to the remaining treatments. All treatment combinations completely prevented progeny production in Tribolium castaneum (Herbst), T. confusum Jacquelin du Val and in Ephestia cautella (Walker). Residues of deltamethrin, fenvalerate, permethrin and phenothrin were determined and shown to be highly persistent on stored wheat. During milling, residues accumulated in the bran fractions and were reduced in white flour. They were not significantly reduced during baking.  相似文献   

7.
BACKGROUND: Methyl bromide is being phased out for use on stored commodities, as it is listed as an ozone‐depleting substance, and phosphine is the fumigant widely used on grains. However, phosphine resistance occurs worldwide, and phosphine fumigation requires a long exposure period and temperatures of > 15 °C. There is an urgent requirement for the development of a fumigant that kills insects quickly and for phosphine resistance management. This paper reports on a new fumigant formulation of 95% ethyl formate plus 5% methyl isothiocyanate as an alternative fumigant for stored grains. RESULTS: The formulation is stable for at least 4 months of storage at 45 °C. A laboratory bioassay with the formulation showed that it controlled all stages of Sitophilus oryzae (L.), Sitophilus granarius (L.), Tribolium castaneum (Herbst), Rhyzopertha dominica (F.), Trogoderma variabile Ballion and Callosobruchus maculatus (Fabricius) in infested wheat, barley, oats and peas at 80 mg L?1 for 5 days, and in canola at both 40 mg L?1 for 5 days and 80 mg L?1 for 2 days at 25 ± 2 °C. After an 8–14 day holding period, residues of ethyl formate and methyl isothiocyanate in wheat, barley, peas and canola were below the experimental permit levels of 1.0 and 0.1 mg kg?1. However, fumigated oats needed an 18 day holding period. CONCLUSIONS: The findings suggest that the ethyl formate plus methyl isothiocyanate formulation has potential as a fumigant for the control of stored‐grain insect pests in various commodities. Copyright © 2011 Society of Chemical Industry  相似文献   

8.
The fumigant toxicity of various volatile constituents of essential oils extracted from sixteen Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae), was determined. The most potent toxicity was found in the essential oil from Mentha arvensis L var piperascens (LC50 = 45.5 µl litre?1 air). GC–MS analysis of essential oil from M arvensis showed it to be rich in menthol (63.2%), menthone (13.1%) and limonene (1.5%), followed in abundance by β‐pinene (0.7%), α‐pinene (0.6%) and linalool (0.2%). Treatment of S oryzae with each of these terpenes showed menthone to be most active (LC50 = 12.7 µl litre?1 air) followed by linalool (LC50 = 39.2 µl litre?1 air) and α‐pinene (LC50 = 54.9 µl litre?1 air). Studies on inhibition of acetylcholinesterase activity of S oryzae showed menthone to have a nine‐fold lower inhibitory effect than menthol, despite menthone being 8.1‐fold more toxic than menthol to the rice weevil. Different modes of toxicity of these monoterpenes towards S oryzae are discussed. © 2001 Society of Chemical Industry  相似文献   

9.
In laboratory experiments, whole wheat was treated with pirimiphos-methyl or carbaryl or combinations of these two insecticides; the treated grain was then adjusted to a 12% moisture content and stored at 25°C for bioassay at various intervals over a period of 39 weeks. Pirimiphos-methyl at 5.1 mg kg?1 effectively controlled Sitophilus granarius (L.) and Tribolium confusum Jacquelin du Val but was ineffective against Rhyzopertha dominica (F.) CRD 118, a strain showing malathion resistance. Conversely, carbaryl at 6.5 mg kg?1 (but not at 3.1 mg kg?1) was effective against R. dominica, but ineffective against the other two species. A combination of pirimiphosmethyl + carbaryl, at 1.8 + 5.1 mg kg?1, controlled S. granarius and R dominica but not T. confusum, whilst a 4.2 + 3.4 mg kg?1 combination was relatively more effective against T. confusum but less so against R. dominica. In a separate experiment, whole wheat was treated with carbaryl at 2.5, 5.0 and 7.5 mg kg?1 (nominal rates). Samples were stored and, at various times after the treatments, were bioassayed with R. dominica CRD 2, at 20, 25, 30 and 35°C. The results were comparable with those for the CRD 118 strain, but efficacy was reduced at higher temperatures. The combination of pirimiphos-methyl at 4–5 mg kg?1 and carbaryl at 5–6 mg kg?1 is suggested as a potentially useful grain protectant where R. dominica is a problem and long term storage is required. These results are discussed in relation to the protection of stored grain in Australia.  相似文献   

10.
Duplicate experiments were carried out on bulk sorghum stored in South Queensland and in Central Queensland. Bioassays of treated grain, conducted during 6 months' storage, established that fenitrothion (12 mg kg?1)+ bioresmethrin (1 mg kg?1), and pirimiphos-methyl (4 mg kg?1)+ carbaryl (8 mg kg?1), controlled typical malathionresistant strains of Sitophilus oryzae (L.), Rhyzopertha dominica (F.), Tribolium castaneum (Herbst), and Ephestia cautella (Walker). Chlorpyrifos-methyl (10 mg kg?1)+ pyrethrins (1.5 mg kg?1)+ piperonyl butoxide (12 mg kg?1), and fenitrothion (12 mg kg?1)+ (1R)-phenothrin (1 mg kg?1), also controlled the strains of S. oryzae, T. castaneum and E. cautella, but were only partly effective against R. dominica. Methacrifos (15 mg kg?1) controlled all the tested species except E. cautella. Chemical assays established that the residues and rates of breakdown of these grain protectants on sorghum conformed to the general pattern for other cereal grains; residues from the above treatments were below the individual Maximum Residue Limits recommended by the Codex Alimentarius Commission.  相似文献   

11.
BACKGROUND: Vapormate? is a cylinderised non‐flammable mixture of ethyl formate (16.7% by weight) and carbon dioxide (CO2) that has been developed as a rapid fumigant of stored grain. Four field trials were undertaken on wheat in 50 t farm silos to demonstrate the feasibility of dynamic application. To assess treatment efficacy, each trial tested mixed stages of Rhyzopertha dominica F. (>11 000), Tribolium castaneum (Herbst.) (>1500) and Sitophilus oryzae (L.) (>13 000) in mesh cages positioned through the centre of the grain bulk and on the grain surface. Ethyl formate and CO2 concentrations were measured in the silo during fumigation and in ambient air outside the 6 m fumigation zone. Application rates of 420, 660 and 940 g m?3 of ethyl formate/CO2 formulation and exposure times of 24, 3 and 72 h, respectively, were examined using wheat of 10.4–11.7% moisture content and grain temperatures between 2 and 32 °C. RESULTS: All life stages of R. dominica and T. castaneum were fully controlled under all conditions tested, and mortality of all life stages of S. oryzae was greater than 98%. CONCLUSION: Dynamic application of vaporised ethyl formate and CO2 to 50 t silos proved safe to operators and rapidly effective against stored‐grain insects on cold to warm grain. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd  相似文献   

12.
The commercially available trap WB Probe II Trap have been used in laboratory to monitor insects activity in grains at 24±1°C and 70±5% r.h.. The major coleopteran pests of cereals in Italy,Oryzaephilus surinamensis (L.),Rhyzopertha dominica (F.),Sitophilus oryzae (L.) andTribolium castaneum (Herbst), were added to the grain at about 0.9 insect per kg. Two tests were prepared: in the testA insect activity was observed in spring wheatTriticum aestivum, L.; in the testB were compared in oat grainAvena sativa L., spring wheatTriticum aestivum L. and maize grainZea mays L. Significant differences in the numbers of insects collected by the traps were observed, both when compared across traps and cereal types. In all cereals considered traps trapped moreS. oryzae thanT. castaneum andO. surinamenis; the species less trapped wereR. dominica.  相似文献   

13.
The present study examined the morphological and physiological effects of amorphous diatomaceous earth against the stored product pestsS. granarius, T. molitor andT. confusum. Diatomaceous earth, namely Fossil Shield? and Dryacide? increased the mortality rate of this insects. After contact with Fossil Shield? the individuals ofS. granarius had significant lost of weight and reduced their water content respectively. This showed that silica dusts break the water barrier of the cuticle. However, it increases the transpiration rate of water across the cuticle and the insect died past several times through dehydration. As well, an addition of food affected the effectiveness of dusts against insects. A lot of stored product beetles will be able to produce metabolic water of feed substrates. This ability protects and weaves contrary to the loss of water. Diatomaceous earth’s can be effective primarily through the sorptive properties of the hygroscopic particles. One day after dust treatment a significant weight loss ofT. molitor pupae was recorded. The exposure to the silica dust Fossil Shield? caused partly an incomplete metamorphosis and death of the individuals. Pupae dipped in Fossil Shield? or abrasive aluminium dust and rolled for further five minutes, reduced not significant higher their weight as unrolled exuvial stages. The morphological analyses of treated insects under the Scanning Electron Microscope showed, that the dust covered the hole integument. Partly, the silica particles sunk into the cuticle. After application of Fossil Shield? at the cuticle of adults,T. molitor, did not show any wax layer. Also it could not be found once blocked by stigma of the mealworm. The dust particles accumulated around the respiration openings and they partly overgrew.   相似文献   

14.
The present study examined the morphological and physiological effects of amorphous diatomaceous earth against the stored product pestsS. granarius, T. molitor andT. confusum. Diatomaceous earth, namely Fossil Shield? and Dryacide? increased the mortality rate of this insects. After contact with Fossil Shield? the individuals ofS. granarius had significant lost of weight and reduced their water content respectively. This showed that silica dusts break the water barrier of the cuticle. However, it increases the transpiration rate of water across the cuticle and the insect died past several times through dehydration. As well, an addition of food affected the effectiveness of dusts against insects. A lot of stored product beetles will be able to produce metabolic water of feed substrates. This ability protects and weaves contrary to the loss of water. Diatomaceous earth’s can be effective primarily through the sorptive properties of the hygroscopic particles. One day after dust treatment a significant weight loss ofT. molitor pupae was recorded. The exposure to the silica dust Fossil Shield? caused partly an incomplete metamorphosis and death of the individuals. Pupae dipped in Fossil Shield? or abrasive aluminium dust and rolled for further five minutes, reduced not significant higher their weight as unrolled exuvial stages. The morphological analyses of treated insects under the Scanning Electron Microscope showed, that the dust covered the hole integument. Partly, the silica particles sunk into the cuticle. After application of Fossil Shield? at the cuticle of adults,T. molitor, did not show any wax layer. Also it could not be found once blocked by stigma of the mealworm. The dust particles accumulated around the respiration openings and they partly overgrew.  相似文献   

15.
Wettable powder formulations of the organophosphorus insecticides, fenitrothion and pirimiphos-methyl, and the pyrethroids, permethrin and deltamethrin, have been compared for persistence and activity on woven polypropylene fabric; the residues produced in maize kept under the test sheets have also been measured. The test insects were Sitophilus oryzue (L.) and Tribolium custuneum (Herbst). Permethrin at 41 and 83 mg m?2 was completely effective for the full 12 weeks of the experiment. Deltamethrin at 6.2 and 12.5 mg m?2 was almost equally effective but after 4 weeks the deposit was slower acting against S. oryzae. The organophosphorus compounds were effective only up to 2 weeks at 250 mg m?2 and up to 4 weeks at 500 mg m?2. No residues could be detected under the pyrethroids but the organophosphorus insecticides gave residues of 2–4 mg kg?1 on a thin layer of grain. This residue was biologically effective against the test insects.  相似文献   

16.
The toxicity of allyl alcohol as a fumigant was assessed for adults ofTribolium castaneum (Herbst.),Rhyzopertha dominica (F.) andSitophilus oryzae (L.). Fumigations were carried out in 3.4–1 glass containers at concentrations of 1–15 mg/l for 3 h. The most sensitive species wasS. oryzae and the most tolerant wasT. castaneum. A dose of 15 mg/l for 3 h was lethal to all three species tested. The feasibility of proposing allyl alcohol as a candidate fumigant is discussed. Publication of the Agricultural Research Organization.  相似文献   

17.
S,S-Di-isobutyl N ethylethylenebis(thiocarbamate) (R-31026) had a strong morphogenetic effect, acting by contact on the newly formed pupae of Tribolium confusum and Tribolium castaneum and thereby disrupting adult development. At a dietary concentration of 20 mg kg?1, 95% of pupae of T. confusum produced pupa-adult intermediates; T. castaneum pupae were affected to a smaller extent. Topical application with 0.002 μg per 0–24-h-old pupa of T. confusum resulted in the formation of 88% malformed intermediates. The larvae brought into contact with R-31026 were not affected and pupated normally, hence the compound differs in its activity from that of a typical juvenile hormone compound. On the other hand, the pupal morphogenetic activity of R-31026 resembles that of the typical juvenoid compound 3-[5-(4-ethylphenoxy)-3-methylpent-3-enyl]-2,2-dimethyloxirane (R-20458). The progeny of the emerging adults from pupae treated with either R-20458 or R-31026 were strongly affected. The effective dosages were far below those required for pupal morphogenetic activity. Biochemical studies showed an increase in the soluble protein fraction during the pupal stage after treatment with either R-31026 or R-20458 indicating disturbances in protein build-up. The bis(thiocarbamate) R-31026 has more favourable practical properties than R-20458 for controlling agricultural insects, because it does not prolong the larval feeding stage.  相似文献   

18.
The polyamine analogue, keto-putrescine, was shown to provide substantial control of infections by six economically important plant pathogens, with EC50 values ranging between 57 and 82 mg litre?1. However, keto-putrescine was relatively less effective in vitro against Phytophthora infestans, Pyricularia oryzae and Pyrenophora avenae, with EC50 values ranging from 145 to 340 mg litre?1. In contrast, the polyamine analogue N-acetylputrescine had to effect on in-vitro growth of P. avenae or P. oryzae or infection of barley seedlings with powdery mildew. When P. avenae was grown in the presence of keto-putrescine, there were small, insignificant reductions in ornithine decarboxylase activity, with more substantial, significant reductions in S-adenosylmethionine decarboxylase activity. These changes were accompanied by a 43% reduction in spermidine concentration and increased concentrations of spermine and cadaverine.  相似文献   

19.
A modified leaf disc buoyancy procedure for the detection of photosynthesis-inhibiting residues in water is described. The modifications proposed, mainly the presence of sodium hydrogen carbonate in the infiltration solution, increased the sensitivity of the method and reduced the time required. The substituted urea and 1,3,5-triazine herbicides diuron, linuron, monuron, atrazine, ametryn and atraton were detected below 0.7 mg litre?1 using cucumber (Cucumis sativus L., cv. ‘Dalia’) leaf discs. A concentration as low as 0.09 mg diuron litre?1 could be detected. Although bean (Phaseolus vulgaris L., cv. ‘Bulgarian’) leaf tissue was less sensitive in this bioassay than cucumber, 0.3 mg diuron litre?1 could still be detected. The test, being very rapid (less than 30 min per determination) and relatively sensitive, could be used for the detection of photosynthesis inhibitors in recycled water used for irrigation.  相似文献   

20.
Ephestia elutella larvae in diapause were exposed at 25°C to methyl bromide at 12 mg litre?1 for 3.5 or 7.5 h and then immediately exposed to a lower concentration. The minimum effective concentration (that at which Haber's rule, concentration × time = k, a constant for mortality, still applied) was about 3 mg litre?1 in tests with no previous exposure toa high concentration, but it was about 2.5 mg litre?1 for individuals surviving a 3.5 h exposure to 12 mg litre?1, and was about 1.6 mg litre?1 for those surviving a 7.5 h exposure to 12 mg litre?1. These exposures to 12 mg litre?1, respectively, killed 2–20% and 50–75% of larvae exposed, and hence the smaller the proportion of survivors of exposure to a high concentration, the lower the minimum effective concentration needed against them. Thus the low concentration persisting at the end of a practical fumigation should contribute significantly to the success of the treatment and be much more effective than any similar low concentration present soon after the introduction of gas.  相似文献   

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