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1.
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   

2.
BACKGROUND: Many plant essential oils show a broad spectrum of activity against pests. This study investigated the effects of two essential oils on Tetranychus urticae, one of the most serious pests in the world. RESULTS: The chemical composition of the two oils was characterised by GC‐MS. The most abundant component in the Santolina africana (Jord. & Fourr) oil was terpinen‐4‐ol (54.96%), while thymol (61%) was prevalent in the Hertia cheirifolia (L.) oil. Mortality and fecundity were measured upon treatment with oil concentrations ranging from 0.07 to 6.75 mg L?1 with a Potter spray tower. Mite mortality increased with oil concentration, with LC50 values of 2.35 mg L?1 for S. africana and 3.43 mg L?1 for H. cheirifolia respectively. For both oils, a reduction in fecundity was observed at concentrations of 0.07, 0.09 and 0.29 mg L?1. Artificial blends of constituents of oils were also prepared and tested with individual constituents missing from the mixture. The results showed that the presence of all constituents was necessary to equal the toxicity of the two natural oils. CONCLUSION: S. africana and H. cheirifolia oils can provide valuable acaricide activity with significantly lower LC50 values. Thus, these oils cause important mortality and reduce the number of eggs laid by females. Copyright © 2012 Society of Chemical Industry  相似文献   

3.
BACKGROUND: The composition and bioactivity of essential oils from Tagetes terniflora Kunth, Cymbopogon citratus Stapf. and Elyonurus muticus (Spreng) Kuntz were evaluated against stored‐grain pests. RESULTS: Fumigant and contact toxicities were observed with T. terniflora on adults of both pests. In contact toxicity, this oil was less toxic to Tribolium castaneum (Herbst). Essential oils from C. citratus and E. muticus showed contact toxicity on S. oryzae. All essential oils produced: (a) repellency on larvae and adults of T. castaneum and adults of Sitophilus oryzae (L.); (b) post‐ingestive toxicity on T. castaneum larvae and S. oryzae adults and alteration of nutritional index on T. castaneum and S. oryzae adults. Cymbopogon citratus reduced the relative growth rate and the efficiency of conversion of ingested food in T. castaneum larvae. Tagetes terniflora produced a feeding stimulant effect in T. castaneum adults. In addition, they had a feeding deterrent action against S. oryzae adults. The composition of essential oils from C. citratus and E. muticus varied only in one component. CONCLUSION: These results showed that the essential oils from T. terniflora, C. citratus and E. muticus should be studied further for their use in integrated pest management programmes for T. castaneum and S. oryzae control. Copyright © 2011 Society of Chemical Industry  相似文献   

4.
BACKGROUND: The pea aphid, Acyrthosiphon pisum (Harris), is a cosmopolitan pest that attacks a wide range of legume crops and vectors important plant virus diseases. In this project, essential oils from the leaf (L) and bark (B) of Laurelia sempervirens (Ruiz & Pavón) Tul. (L) and Drimys winteri JR Forster & G Forster (D) were extracted, and their deterrent and insecticidal activities were tested under laboratory conditions. RESULTS: By use of GC‐MS, safrole was found as the main constituent in LL and LB oils, while the main constituents were more diverse in DL and DB oils. In the deterrent bioassays with A. pisum under choice conditions, the four oils were active, with LL being the most active, followed by LB, DB and DL. The respective deterrence indices were 1.0, 0.89, 0.87 and 0.46 when aphids were exposed for 24 h to 4 µL mL?1. Although there was no aphid mortality when oils were sprayed on faba bean leaves before aphid infestation, there was 58 and 42% mortality when settled aphids were directly sprayed with 4.0 µL mL?1 of LL and LB respectively; DB and DL oils caused ≤18% mortality. In a third series, the essential oils of LL and LB caused 100% mortality when applied at a dose of 64 µL L?1 air by fumigation to faba bean plants infested with A. pisum; at the same dose, DB and DL oils caused 68 and 63% mortality respectively. When fumigation was limited to 2 h, the respective LC50 values for LL and LB oils were 10.6–14.3 µL L?1 air and 9.8–13.2 µL L?1 air. CONCLUSION: Because of their high deterrent and insecticidal activities, the essential oils from leaf and bark of L. sempervirens may be explored as potential natural aphicides. Copyright © 2010 Society of Chemical Industry  相似文献   

5.
BACKGROUND: The activity of several garlic oil ingredients against Culex pipiens L. larvae was studied. In addition to diallyl sulfide (DS) and diallyl disulfide (DDS), the garlic oils used included one essential oil (EO) and two semi‐synthetic garlic essential oils (SSGEO1 and SSGEO2), which resulted from the enrichment of EO with DS and DDS standards respectively. The oils were compared with respect to their toxicity. RESULTS: The chemical composition of the tested oils was evaluated by means of gas chromatography–mass spectrometry. Experimental data from the tested samples revealed high toxicity. In detail, DDS (6.09 mg L?1) was the most active, followed by SSGEO2 (7.05 mg L?1) and EO (8.01 mg L?1), while SSGEO1 and DS were relatively inactive. CONCLUSION: The addition of DDS to EO did not change the toxic effect of the essential oil, whereas the presence of DS in excess produced an enriched essential oil with low toxicity. Furthermore, the antagonistic effect of DS and DDS against the other components of EO was shown by the application of two equations obtained from the literature. Their larvicidal performances were correlated, for the first time, with their detailed chemical composition. Data analysis strongly indicated the toxicity of the other EO sulfur ingredients. Copyright © 2008 Society of Chemical Industry  相似文献   

6.
Abstract

Aleuroclava jasmini (Hemiptera: Aleyrodidae) is a major insect pest of paper mulberry (Broussonetia papyrifera) in Iran, negatively affecting its production. Considering the importance of oils in the integrated management programs of such pests, the present study examined the possibility of whitefly control on paper mulberry plant to assess mortality rate (MR), synergistic rate (SR), resistance rate (RR), and lethal concentration for 50% of the population (LC50) of oils and common insecticide in populations from four areas of Tehran, Iran (one susceptible and three non-susceptible). The best chemical treatments against A. jasmini adults and nymphs in paper mulberry plants were neem oil (1?ml L?1) mixed with deltamethrin (0.5?ml L?1) or with buprofezin (1?ml L?1). The neem, akylarylpolyglyglycol ether and volk oils mixed with deltamethrin or buprofezin also had synergistic effects on adults and nymphs of A. jasmini, respectively, in Azadi, Shahrake Gharb, and Vanak areas (non-susceptible populations), but with higher concentrations (> LC50) and lower SR than in Garm Dareh area (susceptible population). We observed that A. jasmini adults showed the greatest resistance to deltamethrin in Vanak area and nymphs of this pest to buprofezin in Shahrake Gharb area.  相似文献   

7.
BACKGROUND: Sex pheromones of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) are ideal tools to monitor pest flight activity but are not used as means of control. The aim of the present study was to test the suitability of an attract‐and‐kill strategy consisting of pure pheromones and the contact insecticide cyfluthrin as the active ingredient, formulated with plant oils and ultraviolet absorbers, and applied in droplet sizes of 100 µL. RESULTS: Cyfluthrin at a concentration of 5 g L?1 resulted in the highest and fastest killing of males after 48 h, with a 100% mortality after 3–4 days. In contrast, control males survived for 13 days. In olfactometer experiments, the pheromone concentration of 0.5 g L?1 was significantly most attractive against eight virgin females. At controlled conditions (20 °C), no reduction in efficacy of the attract‐and‐kill formulation was observed for a minimum period of 36 days, whereas under natural environmental conditions the efficacy reduced gradually after day 6 of exposure. The longer the droplet was exposed, the longer was the time to reach 100% mortality of males. CONCLUSIONS: Compared with attract‐and‐kill studies for other pest species, the results are promising as a means of achieving highly effective control of potato tuber moths under field conditions. Copyright © 2010 Society of Chemical Industry  相似文献   

8.
BACKGROUND: Straight‐chain, saturated fatty acids (particularly C8, C9 and C10) have some known behavioral effects on insects such as mosquitoes, and were tested in combination for potential repellency/antifeedant activity in bioassays against three significant muscoid flies of medical/veterinary importance: houseflies, horn flies and stable flies. RESULTS: Mixtures of C8, C9 and C10 (1:1:1; 15% total actives in formulation) were highly repellent to houseflies and horn flies at or below 1 mg formulation cm?2. Repellency time varied from < 1 day for houseflies to usually at least 3 days for horn flies. Individual longer‐chain‐length fatty acids were tested, and C11 repelled houseflies for up to 5–8 days, while C12 lasted 2 days. Minimum statistically significant repellency levels of the C8, C9 and C10 mixture (3 h after application) against horn flies were 0.06–0.12 mg cm?2. A liquid formulation of the 15% C8, C9 and C10 mixture in a silicone oil carrier (at 2.8 mg AI cm?2) was highly repellent against hungry stable flies in a blood‐feeding membrane bioassay for at least 8 h. CONCLUSION: The low toxicity and reasonable activity and persistence of these carboxylic acids make them good candidates for development as protective materials against pest flies in livestock settings. Copyright © 2009 Society of Chemical Industry  相似文献   

9.
The aim of this study was to test the botanical family of Asteraceae as a source of natural herbicides. Twenty Asteraceae species were collected during flowering time and evaluated in terms of the yield and quality of essential oils (germination inhibition and growth of weeds). Half the species showed a sufficient yield of essential oil (from about 0.1% to 1.43%) when testing these phytochemicals in vitro as germination inhibitors of two typical weeds, Amaranthus retroflexus and Setaria viridis. Despite the higher tolerance of S. viridis, the concentration of 100 μg L?1 of essential oils of the two Artemisia species and Xanthium strumarium could totally inhibit germination. In addition, at 10 μg L ?1, the same essential oils showed full inhibition of A. retroflexus seeds. A comparison of their effectiveness at suboptimal doses led to a further selection of the most promising sources of essential oils. After their chemical characterisation, the essential oils were tested as post‐emergence herbicides on seedlings of the above‐cited weeds. After spraying the weeds at different concentrations (10, 100 and 1000 mg L?1) during two different phenological stages of weed seedlings (cotyledons and the third true leaf), the essential oils of Artemisia annua and X. strumarium showed the best performance. The essential oils of X. strumarium were then tested again on both weeds to monitor the dynamics of plant injury. A reduction in plant fresh weight (about 20%–30% after 10 days) and chlorophyll content (destroyed, after the same amount of time) was found, thus confirming the total and rapid effectiveness of these essential oils. In summary, A. annua and X. strumarium have elicited considerable agronomic interest and appear to be suitable as a source of essential oils to act as natural herbicides.  相似文献   

10.
The allelopathic potential of Mikania micrantha H.B.K. to affect the seed germination and seedling growth of Coix lacryma‐jobi L. was investigated. Water‐soluble allelopathic substances were found in the water extracts of M. micrantha. The effect of the water extracts on the seed germination and seedling growth of C. lacryma‐jobi was concentration‐dependent. The water extracts from the different plant parts (leaf, stem, and root) of M. micrantha differed in their effect on the germination and seedling growth of C. lacryma‐jobi, with the effect of the leaf extract being the least inhibitory. The malondialdehyde (MDA) content in the C. lacryma‐jobi seedlings increased by 64%, 45%, and 52% of the control with increasing concentrations of the extracts of the root, stem, and leaf (80, 400, and 400 g L?1, respectively). The extract from the M. micrantha roots significantly increased the catalase (CAT) activity of the C. lacryma‐jobi seedlings (48% and 54% of the control at the concentrations of 20 g L?1 and 80 g L?1, respectively). The extracts from the leaves and stems at low concentrations increased the CAT activity, but at high concentrations, the extracts decreased the CAT activity. The extracts from the roots, stems, and leaves at concentrations of 80, 400, and 400 g L?1 also significantly decreased the peroxidase (POD) activity of the C. lacryma‐jobi seedlings to 27%, 52%, and 34% of the control, respectively. These results indicate that the water extracts of M. micrantha could inhibit the seed germination and seedling growth of C. lacryma‐jobi through the regulation of anti‐oxidase activity, such as POD and CAT in the cells. The growth inhibition of the C. lacryma‐jobi seedlings is probably related to injury after oxidization of the cell membranes with the increase of MDA content.  相似文献   

11.
BACKGROUND: Plant essential oils have been recognised as an important natural source of insecticide. This study analysed the chemical constituents and bioactivity of essential oils that were isolated via hydrodistillation from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) against eggs, second instar and adults of Nezara viridula (L.). RESULTS: The major component of oregano was p‐cymene, and, for thyme, thymol. The ovicidal activity was tested by topical application; the essential oil from thyme was more effective. The fumigant activity was evaluated in an enclosed chamber; the LC50 values for oregano were 26.8 and 285.6 µg mL?1 for nymphs and adults respectively; for thyme they were 8.9 µg mL?1 for nymphs and 219.2 µg mL?1 for adults. To evaluate contact activity, a glass vial bioassay was used; the LC50 values for oregano were 1.7 and 169.2 µg cm?2 for nymphs and adults respectively; for thyme they were 3.5 and 48.8 µg cm?2 respectively. The LT50 analyses for contact and fumigant bioassays indicated that thyme was more toxic for nymphs and adults than oregano. Both oils produced repellency on nymphs and adults. CONCLUSION: These results showed that the essential oils from O. vulgare and T. vulgaris could be applicable to the management of N. viridula. Copyright © 2011 Society of Chemical Industry  相似文献   

12.
BACKGROUND: The current study investigates, for the first time, the mosquito larvicidal activities of leaf and twig essential oils from Clausena excavata Burm. f. and their individual constituents against Aedes aegypti L. and Aedes albopictus Skuse larvae. The yields of essential oils obtained from hydrodistillation were compared, and their constituents were determined by GC‐MS analyses. RESULTS: The LC50 values of leaf and twig essential oils against fourth‐instar larvae of Ae. aegypti and Ae. albopictus were 37.1–40.1 µg mL?1 and 41.1–41.2 µg mL?1 respectively. This study demonstrated that C. excavata leaf and twig essential oils possess mosquito larvicidal activity, inhibiting the growth of mosquito larvae for both species at a low concentration. In addition, results of larvicidal assays showed that the effective constituents in leaf and twig essential oils were limonene, γ‐terpinene, terpinolene, β‐myrcene, 3‐carene and p‐cymene. The LC50 values of these constituents against both mosquito larvae were below 50 µg mL?1. Among these effective constituents, limonene had the best mosquito larvicidal activity, with LC50 of 19.4 µg mL?1 and 15.0 µg mL?1 against Ae. aegypti and Ae. albopictus larvae respectively. CONCLUSION: The findings suggested that the essential oils from Clausena excavata leaf and twig and their effective constituents may be explored as a potential natural larvicide. Copyright © 2008 Society of Chemical Industry  相似文献   

13.
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   

14.
BACKGROUND: The use of Trichogramma species is a potential key strategy in integrated pest management. However, its effectiveness depends on the use of chemicals that do not interfere with parasitism and parasite population growth. Here, a study was made of the effects of synthetic insecticides on Trichogramma pretiosum and Trichogramma exiguum in different hosts (Ephestia kuehniella, Plutella xylostella and Spodoptera frugiperda) and the influence of International Organisation for Biological Control (IOBC/WPRS) methodology in selectivity studies using different Trichogramma species. The insecticides used were commercial formulations (triflumuron at a concentration of 0.2 mL L?1 water, etofenprox at a concentration of 0.47 mL L?1 water and endosulfan at a concentration of 7.5 mL L?1 water); the control treatment consisted of distilled water. Eggs attached to cardboard cards were offered to parasitoids inside glass cages. Parasitised eggs, parasitism and adult emergence rates and parasitism reduction were evaluated. RESULTS: Endosulfan and etofenprox, classified as class‐4 toxic products, were extremely toxic to the parasitoids. Triflumuron, classified as a non‐toxic product, was selective to the parasitoids in eggs of all hosts. CONCLUSIONS: The methodology recommended by IOBC/WPRS influenced results regarding the use of different species of parasitoids, and the use of a single parasitoid species in their experiment is questionable. Copyright © 2011 Society of Chemical Industry  相似文献   

15.
BACKGROUND: Natural limonoids are one group of compounds being studied for their insecticidal properties. To discover new limonoids with better activities, analogs were prepared via acylation and hydrolysis, and bioassayed. RESULTS: Analogs were identified using one‐ and two‐dimensional (COSY, HMQC and HMBC) 1H and 13C NMR, IR and MS. 3‐O‐Isovalerylswietenolide (13) and 3‐O‐isobutyrylswietenolide (14) showed excellent antifeedant activity, with DC50 values of 0.19 and 0.009 mg L?1 respectively, compared with the natural limonoid swietenolide (80.6 mg L?1) against fourth‐instar Spodoptera frugiperda (JE Smith) larvae. CONCLUSION: This work shows that limonoid analogs prepared through semi‐synthesis can be used as lead compounds for the development of new insecticides. Copyright © 2010 Society of Chemical Industry  相似文献   

16.
In vitro assay procedures for measuring the activity of cysteine biosynthesis from serine (CBS), which is a coupled reaction catalyzed by serine acetyltransferase and cysteine synthase, were developed using crude extracts from sorghum shoots. Cysteine biosynthesis from serine activity was dependent on acetyl‐CoA concentrations (up to 1.5 mmol L?1), serine (at least up to 20 mmol L?1) and sulfide (up to 0.25 mmol L?1), respectively, and was proportional to the protein concentration in the reaction mixture below 0.4 mg mL?1. The reaction rate was 6.6 nmol min?1 per mg of protein during the first 5 min, but increased to 45.6 nmol min?1 per mg of protein between 30 and 45 min after reaction initiation. Sorghum had the highest CBS total activity (222.4 nmol min?1 per g of fresh weight), and large crabgrass had the lowest CBS total activity (4.7 nmol min?1 per g of fresh weight) when CBS activity in shoots was extracted from sorghum, corn, johnsongrass, barnyardgrass, goosegrass, green foxtail and large crabgrass. Similar results were obtained for CBS specific activity (nmol min?1 per mg of protein). There was no correlation between total CBS activity and susceptibility to metolachlor; however, when corn was excluded, a correlation of R2 = 0.690 was found. Flurazole seed treatment (1.25 g per kg of seed) conferred metolachlor resistance by sorghum, and enhanced total CBS activity and non‐protein thiol content by 27 and 61%, respectively. The increase in thiol content presumably contributed to metolachlor tolerance in sorghum. From these results, the difference in CBS activity partially contributes to the selectivity to metolachlor among certain grass species, and to the safening action of flurazole by increasing thiol content.  相似文献   

17.
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   

18.
Eighteen of 21 naturally occurring compounds and plant extracts tested in an in-vitro feeding system deterred northern fowl mites, Ornithonyssus sylviarum (Canestrini and Fanzago), from feeding. At 1.0% (w/v) concentrations in chicken blood, five compounds killed all mites exposed to them. Citronellal and bay extract prevented mite feeding completely at 0.1% concentrations. None of the compounds or extracts had repellent activity when mites were surrounded by a ring of the test material (0–42 mgcm?2) impregnated in filter paper.  相似文献   

19.
Tepraloxydim [(EZ)‐(RS)‐2‐{1‐[(2E)‐3‐chloroallyloxyimino]propyl}‐3‐hydroxy‐5‐perhydropyran‐4‐ylcyclohex‐2‐en‐1‐one] showed high activity against annual bluegrass (Poa annua L.), which is relatively tolerant to sethoxydim [(±)‐2‐(1‐ethoxyiminobutyl)‐5‐[2‐(ethylthio)propyl]‐3‐hydroxycyclohex‐2‐en‐1‐one]. Absorption and translocation rates of tepraloxydim and sethoxydim were higher in P. annua than in Setaria faberi, but the absorption and translocation patterns of tepraloxydim in the two plants were similar to those of sethoxydim. Metabolic rates of tepraloxydim and sethoxydim in P. annua and S. faberi were found to be similar. The concentration for 50% inhibition (I50) of acetyl‐coenzyme A carboxylase (ACCase) with tepraloxydim was approximately 3 × 10?6 mol L?1 for P. annua and 7 × 10?7 mol L?1 for S. faberi. For sethoxydim, the I50 was found to be 2 × 10?6 mol L?1 with the enzyme of S. faberi, while sethoxydim showed a slight effect on ACCase from P. annua activity, even at 10?4 mol L?1. The strong inhibition of ACCase with tepraloxydim is considered to be the major factor contributing to the high herbicidal activity against P. annua. Measuring the whole plant growth response, the ratio of the tepraloxydim I50 dose of P. annua to that of S. faberi (P/S) was found to be 2.4, while the P/S ratio of sethoxydim and a tepraloxydim analog with a propyl chain at R2 were 56.3 and 73.3, respectively. The herbicidal activity against P. annua was remarkably influenced by the length of the R2 alkyl chain, while the effect on S. faberi was not affected. Acetyl‐coenzyme A carboxylase from P. annua also exhibited a higher resistance to the tepraloxydim analog with a propyl chain than to tepraloxydim. These results suggest that a binding site structure of cyclohexane‐1,3‐diones in the ACCase differs between P. annua and S. faberi.  相似文献   

20.
Imazapyr owes its importance in Morocco to its success in controlling the perennial weed Solanumelaeagnifolium Cav., which infests the Tadla area. Persistence and mobility of imazapyr has been studied in two Moroccan soils from the Rabat area, with differing organic matter content (red and organic soils), under laboratory conditions at 75% of their field capacities and 25–28 °C. Residue analysis was performed on the basis of a bioassay test using lentil (Lens culinaris Medic.) as indicator species. The residual activity of imazapyr accounted for 69%, 25%, 50% and 62%, 46%, 66% of the initial activity for the red and organic soils at 1, 5 and 10 mg L?1 respectively. The half-lives varied between 25 and 58 days for the red soil and 55 and 58 days for the organic soil. In the organic soil, imazapyr was highly mobile under the irrigation regime applied. Most of the activity was found in the first 3 × 75 mL of the effluents. A following biotest with the leached soil showed low remaining residual activity.  相似文献   

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