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1.
Dosages (>10 ml mg−1 against Callosobruchus maculatus F. or Sitophilus zeamais Motsch; >20 ml kg−1 against Dermestes maculatus Deg.) of citruspeel oils reduced oviposition or larval emergence through parental adult mortality, but had no residual activity on the eggs or larvae produced by survivors. Oil-treated grains (7 ml kg−1 against C. maculatus) or dried fish (28 ml kg−1 against D. maculatus) which caused 100% mortality 1 h after application lost all activity within 24 h, thus confirming the non-residual nature of the effects. The activity of limepeel oil against test insects was found to be dependent on the time interval between the application of oil and start of bioassays. The non-volatile residues of limepeel oil were not toxic to insects on glass and dried-fish surfaces. Topical toxicity trials against D. maculatus adults also illustrated the relative unimportance of contact toxicity of citrus oils, as appreciable mortality (at application rates of up to 2 μl per insect) was obtained only when treated insects were confined in air-tight glass chambers. The volatility of toxic constituents in the oils was further illustrated by mortality of untreated C. maculatus adults confined in air-tight chambers with topically treated D. maculatus. A more efficient way to use citruspeel essential oils to control insects would be as a fumigant in relatively enclosed or air-tight systems.  相似文献   

2.
BACKGROUND: In a screening programme for new agrochemicals from Chinese medicinal herbs, Chenopodium ambrosioides L. was found to possess strong fumigant activity against the maize weevil Sitophilus zeamais (Motsch.). Essential oil of C. ambrosioides was obtained by hydrodistillation, and the constituents were determined by GC‐MS analysis. The active compounds were isolated and identified by bioassay‐directed fractionation. RESULTS: Five active compounds [(Z)‐ascaridole, 2‐carene, ρ‐cymene, isoascaridole and α‐terpinene] were isolated and identified from the essential oil from Chinese C. ambrosioides. The LC50 values (fumigation) of the crude essential oils and the active compound (Z)‐ascaridole against S. zeamais adults were 3.08 and 0.84 mg L?1 air respectively. The LD50 values (contact toxicity) of the crude essential oil and (Z)‐ascaridole against S. zeamais adults were 2.12 and 0.86 µg g?1 body weight respectively. CONCLUSION: The findings suggested that the essential oil of Chenopodium ambrosioides and its main active constituent, (Z)‐ascaridole, may be explored as a natural potential fumigant. Copyright © 2011 Society of Chemical Industry  相似文献   

3.
The toxicity of the naturally derived insecticide spinosad was tested against the gypsy moth, Lymantria dispar. Bioassays using red oak leaf disks, treated with spinosad in a Potter spray tower, yielded an LC50 value of 0.0015 µg AI cm−2 (3‐day exposure; 13‐day evaluation; 2nd instar larvae). Applied to foliage to run‐off in the laboratory (potted red oak seedlings) and the field (4 m‐tall birch trees), spinosad effectively controlled 2nd instar larvae at concentrations ranging from 3 to 50 mg litre−1. Toxicity in the laboratory, and efficacy and persistence in the field, were comparable to those achieved with the insecticide permethrin. Laboratory studies supported field observations that control was achieved in part by knockdown due to paralysis. In addition, laboratory results demonstrated that crawling contact activity may play an important role in field efficacy; 50% of treated larvae were paralyzed 16 h after a 2‐min crawling exposure to glass coated with a 4 mg litre−1 spinosad solution. © 2000 Society of Chemical Industry  相似文献   

4.
Laboratory studies were conducted to determine the effect of the naturally derived compound spinosad on Ceratitis capitata Wied. (Diptera, Tephritidae). The organophosphate fenthion was used as a standard. Direct dose-dependent mortality and reduced fecundity were observed in oral treatment of adults with spinosad. The LC90 values 14 h and seven days after treatment were 19·50 and 0·49 mg litre−1 respectively. Fenthion was less active (the LC50 eight days after treatment was 1·17 mg litre−1) and did not affect the fecundity of the fly. Adults were also very susceptible to spinosad and fenthion via residual contact. For spinosad, 100% mortality was recorded 48 h after treatment for a dose of 10 mg litre−1. Spinosad was more effective than fenthion in suppressing larval development when neonate larvae were reared on treated diet supplemented with a range of concentrations from 0·02 to 0·83 mg kg−1 diet. Last-instar larvae were much less susceptible to spinosad or fenthion when exposed via dipping or when they pupated in treated medium and both products had similar performance. A lack of ovicidal activity was observed in direct egg-treatments with spinosad but significant reductions from 1 mg litre−1 onwards were recorded for fenthion.  相似文献   

5.
The insecticidal activities of four surfactants (Cide‐kick, Silwet L‐77, M‐Pede and APSA‐80), a dishwashing detergent (New Day), a mineral oil (Sunspray oil), a cotton seed oil and a vegetable oil, alone or in combination, were tested against nymphs of Bemisia argentifolii Bellows & Perring on collards and tomato. Silwet L‐77 was more effective (>95% mortality) than Cide‐Kick or APSA‐80 at rates from 0.25–1.00 g AI litre−1 but caused severe phytotoxicity to tender tomato leaves at all but the lowest rate. New Day dish detergent at 2.0 ml litre−1 caused mortality (95%) comparable to M‐Pede insecticide soap at 10‐fold greater concentration. A New Day ingredient, cocamide DEA, was considerably more active than the other ingredients or the commercial mixture. Additional surfactants added to Sunspray oil increased efficacy in some treatments, but not others. Toxic responses of 2nd‐ and 3rd‐ instar whiteflies to vegetable oil and cotton seed oil at 5.0 and 10.0 ml litre−1 plus 0.4 g AI litre−1 APSA‐80 ranged from 22.1 to 79.9% and 66.3–88.7% mortality, respectively. Whitefly mortality was greater on tomato than on collard in six of seven instances when differences between host plants were significant. Our results indicate that the these surfactants and oils have good potential for controlling B argentifolii. © 2000 Society of Chemical Industry  相似文献   

6.
Several factors which may influence the germination of wheat fumigated with hydrogen cyanide or carbonyl sulphide were investigated. Dosages of hydrogen cyanide ranged from 10 mg litre−1 for 24-h exposure up to 150 mg litre−1 for 96-h exposure. Dosages of carbonyl sulphide ranged from 25 mg litre−1 for 24-h exposure up to 500 mg litre−1 for 72-h exposure. The experiments were conducted on wheat of 11·4, 13·8 and 15·7% moisture content. The higher levels of these fumigants exceed those needed for control of insects in wheat. Germination was not diminished and may have been slightly enhanced with hydrogen cyanide, but was diminished by high levels of carbonyl sulphide in the drier wheat. The plumule length was reduced following all dosages of hydrogen cyanide, but only after high dosages of carbonyl sulphide, especially on the driest wheat. It is concluded that hydrogen cyanide and carbonyl sulphide could be used to control insects in wheat without affecting seed viability, provided that concentrations are carefully controlled.  相似文献   

7.
The chitin synthesis inhibitor diflubenzuron, applied as a wettable powder spray to woven polypropylene at 100–500 mg m?2, was effective against Dermestes maculatus De Geer for at least 12 weeks. D. maculatus was unable to develop on ox hide dipped in a suspension of diflubenzuron (125 mg litre?1), or on fishmeal dusted at 1–10 mg of active ingredient kg?1. Diflubenzuron prevented the development of infestations of Callosobruchus maculatus (L.) on peas and of Acanthoscelides obtectus (Say) on beans dusted at 1–5 mg kg?1. The compound was also very effective against early instar larvae of Trogoderma granarium Everts on wheat. The persistence and activity of diflubenzuron at low dosage rates against D. maculatus appear to justify larger scale trials.  相似文献   

8.
The effects of DPX-MP062 [methyl 7-chloro-2,3,4a,5-tetrahydro-2-[methoxycarbonyl(4-trifluoromethoxyphenyl)carbamoyl] indeno[1,2-e][1,3,4] oxadiazine-4a-carboxylate] a broad-spectrum insecticide with a novel mode of action, on the Egyptian cotton leafworm, Spodoptera littoralis, were studied in laboratory experiments. Egg hatch was affected by high concentrations (125 mg AI litre-1) of DPX-MP062. Larvae that hatched from treated eggs were significantly affected at concentrations of 12·5 mg AI litre-1 and greater. Larvae were fed castor bean leaves treated with DPX-MP062; 1st-instar larvae were the most susceptible development stage. Pupation and adult formation were determined in assays with 5th-instar larvae. There was strong suppression of adult formation; 65 and 91% at 0·5 and 0·75 mg AI litre-1, respectively. Highly affected larvae died before pupation; slightly affected ones reached pupation 2–4 days later, were smaller than larvae in the untreated control, and were sometimes unable to develop into normal adults. Comparatively high concentrations (50 and 100 mg AI litre-1) of the test compound were necessary to affect adults by ingestion, but no effects from contact application could be determined at a concentration of 100 mg AI litre-1. © 1998 Society of Chemical Industry  相似文献   

9.
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   

10.
Eleven sesquiterpene lactone derivatives of parthenin ( 1 ), obtained from wild feverfew, Parthenium hysterophorus, were prepared by chemical and photochemical transformations. The compounds tested were a pyrazoline adduct ( 2 ) of parthenin, its cyclopropyl ( 3 ) and propenyl ( 4 ) derivatives, anhydroparthenin ( 5 ), a dihydro‐deoxygenated product ( 6 ), a formate ( 7 ) and its corresponding alcohol ( 8 ) and acetate ( 9 ), a rearranged product ( 10 ), lactone ( 11 ) and hemiacetal ( 12 ). All these derivatives, along with parthenin, were tried for their antifeedant action against sixth‐instar larvae of Spodoptera litura, for insecticidal activity against the adults of store grain pest Callosobruchus maculatus, for phytotoxic activity against Cassia tora, and for nematicidal activity against the juvenile stage‐II (J2) of the root knot nematode Meloidogyne incognita. Antifeedent bioassay revealed that parthenin is moderately antifeedant. Among the derivatives, the saturated lactone ( 11 ) was found to be about 2.25 times more active than parthenin. The pyrazoline adduct ( 2 ) was found to be the most effective as an insecticide, with LC50 values after 24, 48 and 72 h of 96, 43 and 32 mg litre−1, respectively, which are comparable with neem extract. Compound 4 was found to be the most effective inhibitor of germination and seedling growth of C tora, with ID50 values for germination, plumule length and radicle length of 136, 326 and 172 compared with 364, 738 and 427 mg litre−1, respectively, for parthenin. Compound 10 was found to be the most effective in terms of nematicidal activity. The LC50 values for this compound were 273 and 104 mg litre−1, respectively, after 48 and 72 h compared with 862 and 512 mg litre−1 observed for parthenin after 48 and 72 h. © 2001 Society of Chemical Industry  相似文献   

11.
The essential oils from rosemary (Rosmarinus officinalis L.) and laurel (Laurus nobilis L.) obtained from Mersin Province in Turkey, were tested for their fumigant toxicity against all life stages of confused flour beetle (Tribolium confusum du Val.). GC-MS analysis showed that 1,8-cineole was found to be the major component of both rosemary and laurel essential oils. Vapors of rosemary and laurel essential oils were toxic to all life stages ofT. confusum. Only 65% mortality of the eggs was achieved when exposed to a dose of 172.6 mgl −1 air of rosemary essential oil at the longest exposure period (144 h); at the same dose, the pupae were the most resistant stage, with LT90 (lethal time) value of 120.2 h. The adults were the most resistant stage to laurel essential oil, with LT90 value of 77.2 h. On the basis of LT90 values, tolerance of the life stages ofT. confusum to rosemary and laurel essential oils was, in descending order: pupa < larva < adult, and larva < adult < egg < pupa, respectively. Based on the concentration × time (Ct) products (g hl −1), rosemary essential oil was more toxic than laurel to the adults and larvae ofT. confusum. However, laurel essential oil was more toxic than rosemary to the eggs and pupae. Since these essential oils need such high Ct products to obtain complete mortality ofT. confusum compared with the most commonly used commercial fumigants, it would be impossible to use them on their own as a commercial fumigant against stored-product insects.  相似文献   

12.
The effect of the monooxygenase inhibitor, 1-aminobenzotriazole (ABT) on isoproturon phytotoxicity and metabolism was studied in resistant (R) and susceptible (S) biotypes of Phalaris minor and in wheat (Triticum aestivum). Addition of ABT (2·5, 5 and 10 mg litre-1) to isoproturon (0·25, 0·5, 1, 2 and 4 mg litre-1) in the nutrient solution significantly enhanced the phytotoxicity of isoproturon against the R biotype. Isoproturon at 0·25 mg litre-1 reduced the dry weight (DW) of the S biotype by 77%, whereas the R biotype required 4·0 mg litre-1 for similar reduction. Addition of 10 mg litre-1 of ABT to the 0·25 mg litre-1 isoproturon caused 71 and 82% reduction in DW of R and S biotypes, respectively. Wheat was more sensitive to the mixture of isoproturon and ABT than the R biotype of P. minor. Reduced concentrations of ABT in the mixture from 10 to 2·5 mg litre-1 increased the DW of the R biotype more than that of the S biotype. The R biotype metabolised [14C]isoproturon at a faster rate than the S biotype. ABT (5 mg litre-1) inhibited the degradation of [14C]isoproturon in both biotypes of P. minor and in wheat. In the presence of ABT, about half of the applied [14C]isoproturon remained as parent herbicide in all the three species after two days. The metabolites were similar in the R and S biotypes and wheat as determined by co-chromatography with reference standards and mass spectroscopy (MS). ABT inhibited the appearance of the hydroxy and monomethyl metabolites and their conjugates in all the test plants. These results suggest that the activity of the enzymes responsible for the degradation of isoproturon is greater in the R than in the S biotype of P. minor, resulting in its rapid detoxification. Incorporation of the monooxygenase inhibitor ABT into the nutrient solution greatly inhibited the degradation of [14C]isoproturon in the R biotype and increased its phytotoxicity. Both hydroxylation and N-dealkylation reactions were found to be sensitive to ABT; inhibition of hydroxylation was greater than that of demethylation. Since ABT could not completely suppress isoproturon degradation, it is possible that more than one monooxygenase is involved. © 1998 SCI  相似文献   

13.
The larvicidal component from sawdust of Thujopsis dolabrata var. hondai (Family Cupressaceae) against the pine needle gall midge (Thecodiplosis japonensis) was isolated by chromatographic techniques and characterized by spectral analysis as carvacrol. In a laboratory study using the impregnated filter paper method, carvacrol was more toxic to T. japonensis larvae than β-thujaplicine, cedrol, α-terpinol, thujone or thymol. In field studies with soil injections of carvacrol, this compound exhibited potent larvicidal activity, suggesting that this activity might be attributable to fumigant action. In a test with trunk implantation, a mixture of carvacrol and phosphamidon (0·15+0·15 ml cm-1 diameter at breast height) revealed much more potent larvicidal activity than phosphamidon alone (0·3 ml cm-1 DBH) in spite of little or no larvicidal activity of carvacrol alone (0·3 ml cm-1 DBH), indicating a possible synergistic effect. As a naturally occurring insecticide, carvacrol could be useful as a new preventive agent against damage caused by T. japonensis. © 1997 SCI.  相似文献   

14.
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   

15.
BACKGROUND: The contact + fumigant toxicity of 92 plant essential oils and control efficacy of 18 experimental spray formulations containing nine selected essential oils (0.5 and 0.1% sprays) and six commercial insecticides to females from B‐ and Q‐biotypes of Bemisia tabaci were evaluated using vapour‐phase mortality and spray bioassays. RESULTS: Garlic and oregano (LC50, 0.15 mL cm?3) were the most toxic oils against B‐ and Q‐biotype females. Strong fumigant toxicity to both biotype females was also obtained from catnip, cinnamon bark, clove bud, clove leaf, davana, savory and vetiver Haiti oils (LC50, 0.17–0.48 mL cm?3). The 0.5% sprays of these oils (except for thyme red oil) resulted in 90–100% mortality against both biotype females. Only garlic applied as 0.1% spray provided 100% mortality. Spinosad 100 g L?1 suspension concentrate (SC) treatment resulted in 92 and 95% mortality against both biotype females, whereas acetamiprid 80 g L?1 wettable powder (WP), imidacloprid 80 g L?1 SC, thiamethoxam 100 g L?1 water‐dispersible granule (WDG) and pyridaben 200 g L?1 WP treatments resulted in 89–100% mortality against B‐biotype females only. CONCLUSION: In the light of global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment, the essential oils described, particularly garlic, cinnamon bark and vetiver Haiti, merit further study as potential insecticides for the control of B. tabaci populations as fumigants with contact action. Copyright © 2011 Society of Chemical Industry  相似文献   

16.
Lightbrown apple moth (LBAM), Epiphyas postvittana Walker was used as a test insect to evaluate a post-harvest oil, C15 Ampol CPD, and a spray oil, C23 Ampol DC-Tron NR, both applied as dips. CPD was much more efficacious than C23 DC-Tron NR against exposed third-instar larvae. Higher oil concentrations were required to penetrate and kill larvae sheltering under the calyx of oranges. LBAM eggs were more susceptible to CPD oil than larval stages. LBAM larvae dipped in sub-lethal doses of oil continued to develop, but the fecundity of both males and females was reduced. DC-Tron had a significant effect on egglaying. CPD and C23 DC-Tron NR affected the fertility of eggs laid. CPD oil sprayed at 50 ml litre−1 on adult LBAM moths reduced their fertility. Factors contributing to the higher efficacy of CPD and its potential use as a post-harvest treatment are discussed. © 1999 Society of Chemical Industry  相似文献   

17.
Essential oils extracted fromEucalyptus blakelyi (1,8-cineole, 77.5%),Melaleuca fulgens (1,8-cineole, 56.9%) and 1,8-cineole were shown to have fumigant toxicity against different development stages ofSitophilus oryzae. The eggs ofS. oryzae were the most tolerant, followed by pupae, larvae and adults in that order.M. fulgens oil,E. blakelyi oil and 1,8-cineole at 100 μl per liter of air gave, respectively, LT50 values of 16.2, 17.4 and 9.1 h for adults, 31.1, 19.3 and 17.5 h for larvae, 55.6, 75.2 and 39.7 h for pupae, and required >7 days for eggs. Only 1,8-cineole (200 μl −1 air) gave a significant egg kill by 7 days and the LT95 was 134.5 h. 1,8-Cineole could be a useful new fumigant. http://www.phytoparasitica.org posting Oct. 3, 2004.  相似文献   

18.
Fourteen compounds (paclobutrazol, triadimenol, BAS111..W, propiconazole, tetcyclacis, prochloraz, metyrapone, piperonyl butoxide, 1-aminobenzotriazole, fenpropimorph, propham, prohexadione, mepiquat chloride and chlormequat chloride), most of them established inhibitors of cytochrome P450-dependent mixed function oxygenases and used as pesticides, especially plant growth regulators or fungicides, were applied to the non-target organisms Chlorella fusca and Chlorella sorokiniana, two species of photoautotrophic unicellular green algae. The inhibitory properties of these compounds were evaluated by comparing concentration/response relationships for the integral parameters of cell volume growth and cell division with those for the P450-dependent O-dealkylase activity measured in vivo using 7-ethoxycoumarin and 7-ethoxyresorufin as xenobiotic model substrates for phase-I biotransformation. The results obtained indicate a strong algicidal activity for some of these compounds, with differential sensitivity of the order: cell division>O-dealkylation>cell volume increase. EC50 values for cell division of C. fusca ranged from 0·1 to 9·3 μmol litre−1 for prochloraz and paclobutrazol, respectively. Furthermore, in most cases, concentrations around 10 μmol litre−1 limited significantly the capacity for cytochrome P450 O-dealkylase activity.  相似文献   

19.
Several ethyl 2,3-dihydro-3-oxoisothiazolo[5,4-b]pyridine-2-alkanoate derivatives were synthesized as herbicides. Only 5-methyl derivatives inhibited both hypocotyl and root growth in the lettuce (Lactuca sativa L.) seedling test at 100 mg litre-1. Only ethyl propionate and valerate derivatives showed significant inhibition at 0·1 mg litre-1, whereas ethyl acetate or butyrate derivatives were inactive. Contrary to unoxidized derivatives, the inhibitory effect of 1-oxide and 1,1-dioxide derivatives was strongly dependent on concentration; ethyl 2,3-dihydro-5-methyl-3-oxoisothiazolo[5,4-b]pyridine-2-propionate 1,1-dioxide inhibited 100% of germination at 100 mg litre-1 and 45% of lettuce seedling growth at 0·1 mg litre-1. Quantitative structure–inhibition of growth relationship analysis carried out by adaptive least-squares (ALS) method gave a good correlation with small and hydrophobic 5-substituents as well as with odd carbon-chain ethyl alkanoates in position 2. Active compounds did not show auxin-like activity from 0·1 to 100 mg litre-1. © 1997 SCI.  相似文献   

20.
The performance of low concentrations of methyl bromide against diapausing larvae of Ephestia elutella at 15 and 25°C was assessed in extended exposure periods. At concentrations of 1.9 mg litre?1 and below, test batches required higher concentration-time (ct) products for 100% kill at 25°C than at 15°C. The minimum concentration at which the concentration: time relationship still applied was between 1.3 and 1.9 mg litre?1 at 15°C, whereas at 25°C it was between 2.7 and 4.0 mg litre?1. For many individuals within each population sample, however, lower concentrations at moderate dosage levels remained lethal. At 25°C, a ct product of about 90 mg litre?1 h gave between 53 and 77% kill at 6.1, 4.0, 2.7 and 1.9 mg litre?1. The trends observed suggest that the most tolerant members of the population have an enhanced ability to detoxify methyl bromide at the higher temperature. The implications of the results for the build-up of resistance and for practical control measures are discussed.  相似文献   

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