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1.
Gymnema sylvestre is an important medicinal plant which bears bioactive compound namely gymnemic acids. The present work deals with optimization of cell suspension culture system of G. sylvestre for the production of biomass and gymnemic acid and we investigated effects of macro elements (NH4NO3, KNO3, CaCl2, MgSO4 and KH2PO4 - 0.0, 0.5, 1.0, 1.5 and 2.0× strength) and nitrogen source [NH4+/NO3− ratio of: 0.00/18.80, 7.19/18.80, 14.38/18.80, 21.57/18.80, 28.75/18.80, 14.38/0.00, 14.38/9.40, 14.38/18.80, 14.38/28.20 and 14.38/37.60 (mM)] of Murashige and Skoog medium on accumulation of biomass and gymnemic acid content. The highest accumulation of biomass (165.00 g l−1 FW and 15.42 g l−1 DW) was recorded in the medium with 0.5× concentration of NH4NO3 and the highest production of gymnemic acid content was recorded in the medium with 2.0× KH2PO4 (11.32 mg g−1 DW). The NH4+/NO3− ratio also influenced cell growth and gymnemic acid production; both parameters were greater when the NO3− concentration was higher than that of NH4+. Maximum biomass growth (159.72 g l−1 of FW and 14.95 g l−1 of DW) was achieved at an NH4+/NO3− ratio of 7.19/18.80, and gymnemic acid production was also greatest at the same concentration of NH4+/NO3− ratio (11.35 mg g−1 DW).  相似文献   

2.
A highly efficient regeneration protocol for oilseed crop Crambe abyssinica has been developed using hypocotyls as explants in this study. Crambe is a potential engineering oilseed crop for industrial purposes as it contains 55-60% erucic acid in its oil and, more importantly, it does not outcross with any food oil seed crops. However, the low regeneration frequency with the currently available protocols is still a limiting factor for genetic modification of Crambe. In this study, we investigated the effects of N-source, C-source, AgNO3, cultural conditions as well as the concentration and combination of plant growth regulators (PGR) on the regeneration frequency of C. abyssinica. The results showed that all these factors, especially the N-source and PGR concentrations and combinations, played an important role in shoot regeneration. Among all the factors tested, the combination of using hypocotyls from C. abyssinica cv. galactica, the Lepiovre basal medium supplemented with 16 g l−1 glucose, 0.5 g l−1 AgNO3, 2.2 mg l−1 thidiazuron (TDZ), 0.5 mg l−1 α-naphthaleneacetic acid (NAA), 2.5 g l−1 Gelrite, seeds germinated in dark for 3 days and explants cultured in light, gave the best regeneration frequency (over 95%). The results also suggest that reducing the content of NH4+ or keeping a suitable NO3−/NH4+ ratio in the regeneration medium would be crucial to Crambe shoot regeneration.  相似文献   

3.
The study deals with evaluation of antifungal and antiaflatoxigenic Caesulia axillaris Roxb. essential oil (EO) against herbal raw materials deteriorating fungi and its free radical scavenging activity. During mycoflora analysis these herbal raw materials were found to be severely contaminated by different fungi and aflatoxins. A total of nine different fungal species were isolated from three herbal raw materials. Aspergillus flavus LHPtc was recorded as the highest aflatoxin B1 producing strain. EOs of some plants were tested for their fungitoxicity against the toxigenic strain A. flavus LHPtc, and C. axillaris EO was found as potent fungitoxicant. C. axillaris EO was chemically characterized through GC-MS analysis which depicted the presence of 18 compounds, dl-limonene and Euasarone being the major components. The EO exhibited broad spectrum of fungitoxicity against fungi causing postharvest deterioration of herbal raw materials. At 1.0 μl ml−1 the oil showed complete inhibition of fungal growth and aflatoxin B1 production was inhibited at 0.8 μl ml−1. Free radical scavenging activity of the oil was also recorded by 2,2-diphenyl-1-picrylhydrazyl assay, and its IC50 value was found 18 μl ml−1. The safety limit of the EO was determined in terms of LD50 on mice, which was 9166.6 μl kg−1, suggesting its non mammalian toxicity. The EO of C. axillaris may be recommended as a plant based preservative in enhancement of shelf life of herbal raw materials by preventing their lipid peroxidation as well as biodeterioration due to fungal and aflatoxin contamination.  相似文献   

4.
Soil solarisation together with the application of animal manure has been described as an alternative process for control of Phytophthora capsici root rot in pepper crops. A mixture of fresh sheep manure and dry chicken litter (SCM) and a semi-composted mixture of horse manure and chicken litter (HCM) were applied at 5.1 kg m−2 (dry weight) under plastic sheets to reduce Phytophthora inoculum survival rate and disease incidence. Non-solarised (C) and solarised (S) soils were used as control treatments. Mean NH3 concentration increased in SCM during biodisinfestation process (14.8 mg NH3 m−3) compared with HCM (9.1 mg NH3 m−3), accounted for the higher organic N content and potential N mineralisation. The higher NH3 concentration in SCM could have contributed to reduce the inoculum survival rate (30.6% and 75.0% in SCM and HCM plots, respectively). Inoculum survival rate was not reduced in S (94.4%) as temperature was below 33 °C throughout the experimental period. After biodisinfestation treatment, N2O and CO2 emissions tended to be higher in SCM, despite high spatial variability. Cumulative N2O emissions were 1.31 and 0.42 g N2O-N m−2 in SCM and HCM after 43 days. The larger N application and organic N mineralisation rate on fresh manure amended soils might have contributed to higher N2O emissions during and after soil biodisinfestation by denitrification and nitrification, respectively. Cumulative CO2 emission averaged 211.0 and 159.9 g CO2-C m−2 in SCM and HCM, respectively. The soluble organic C, more abundant in fresh manure, might have favoured soil respiration in SCM. Disease incidence decreased in SCM and HCM plots (disease incidence, 2%-8%) in relation to solarised soils (42%) after 4 months. Microbial suppressiveness might have contributed to minimise Phytophthora disease incidence in SCM and HCM plots. Pepper fruit yield increased with manure amendment in SCM and HCM, which averaged 4.6 and 4.3 kg m−2, respectively. Further research will be necessary to guarantee an effective Phytophthora biodisinfestation by fitting manure N and organic matter applications, improving crop yield and reducing greenhouse gas pollution.  相似文献   

5.
Six actinomycetes isolates, namely Streptomyces toxytricini vh6, Streptomyces flavotricini vh8, S. toxytricini vh22, Streptomyces avidinii vh32, Streptomyces tricolor vh85 and vh41, an isolate of an unknown species of Actinomycetales, were tested for their efficacy in protecting tomato (Solanum lycopersicum) against Rhizoctonia solani under green house conditions. Actinomycetes treated plants showed better growth in terms of high chlorophyll content, higher phenylalanine ammonia lyase (PAL) activity and high total phenolic content. Qualitative and quantitative estimation of phenolic compounds from tomato leaves showed significant accumulation of six phenolic acids, gallic (29.02 μg g−1 fresh leaf wt), ferulic (11.44 μg g−1 fresh wt), cinnamic (56.84 μg g−1 fresh wt), gentisic (24.19 μg g−1 fresh wt), chlorogenic acid (1.72 μg g−1 fresh wt) and salicylic (0.39 μg g−1 fresh wt) acid, in actinomycetes treated plants. Biochemical profiling, when correlated with plant mortality in actinomycetes treated and untreated plants, indicated that isolates vh6 and vh8 offered 44.55% and 40.14% disease reductions, respectively compared to the control. These results established that these organisms have the potential to act as biocontrol agents.  相似文献   

6.
2014、2015年夏季,试验采用单因素随机区组设计,以先玉335为材料,设置两种肥料增效剂、7种施肥方式,研究大喇叭口期和抽雄期植物学性状、施肥后0、14、28、42 d时0~30 cm和31~60 cm土壤中NH_4~+-N和NO_3~--N含量以及收获时玉米穗部性状和产量差异。结果表明,分期施肥比全部氮肥作底肥更能促进夏玉米茎粗、叶面积、气生根数量、穗长、穗行数和行粒数等增加。与对照和不施用肥料增效剂相比,0~30 cm和31~60 cm土层中施用两种肥料增效剂的NH_4~+-N含量较高,NO_3~--N含量较低,控制了NH_4~+/NO_3~-比例。两种肥料增效剂相比,Entrench效果明显优于NMAX。  相似文献   

7.
We test the hypothesis that reduction in grain N concentration under elevated CO2 concentration (e[CO2]) is associated with N types (NH4+ and NO3−) and their ratios. Wheat (Triticum aestivum L. cv. H45) was grown in a glasshouse under two CO2 concentrations (389 μmol mol−1 and 700 μmol mol−1), supplied with equal amount of N with different ratios of NH4+ and NO3−: (i) 100% NO3−–N; (ii) 50% NO3−–N and 50% NH4+–N; and (iii) 25% NO3−–N and 75% NH4+–N. Plant growth, N uptake and partitioning were measured during plant development. Plant biomass and grain yield was increased at e[CO2] when N was supplied as an equal proportion of NO3− and NH4+. Despite the yield increment, grain N concentration was not affected by e[CO2], in 50% NO3−–N treatment. In contrast, grain N concentration decreased in 100% NO3−–N and 25% NO3−–N treatments. In 50% NO3−–N treatment, N uptake during post-anthesis stage (from 69 to 141 days after planting) was significantly stimulated under e[CO2] compared to 100% NO3−–N and 25% NO3−–N treatments. We concluded that supplement of N in an equal proportion of NO3− and NH4+ which increases post-anthesis N uptake, avoid the reduction of grain N concentration under e[CO2].  相似文献   

8.
The present investigation was conducted at Vittal, Karnataka, India during 2004-2007 to study the feasibility of intercropping of medicinal and aromatic plants (MAPs) in arecanut plantation. The results revealed that MAPs can be successfully grown as intercrops in arecanut plantation with increased productivity and net income per unit area. Kernel equivalent yield of MAPs varied between 272 kg ha−1 in case of Piper longum to 1218 kg ha−1 in Cymbopogon flexuosus. Pooled data indicated that Asparagus racemosus produced fresh root yield of 10,666 kg ha−1 of arecanut plantation and contributed to maximum kernel equivalent yield of 1524 kg ha−1 among all medicinal and aromatic plants. Intercropping of MAPs in arecanut was found economical. The net return per rupee investment was highest in C. flexuosus (4.25) followed by Bacopa monnieri (3.64), Ocimum basilicum (3.46) and Artemisia pallens (3.12). The total system productivity of arecanut + MAPs intercropping system varied from 2990 to 4144 kg ha−1. Arecanut + O. basilicum intercropping system registered significantly higher production efficiency 8.2 kg ha−1 day−1 than other systems. Intercropping of MAPs had more positive effect on soil pH in arecanut based cropping system. The soil pH was 5.6 in 2004 and it was 0.3-0.9 units higher in 2007. Soil organic carbon (SOC) content varied significantly due to intercropping of MAPs at the end of experiment. The SOC content increased in Aloe vera, A. pallens, P. longum and B. monnieri, while it depleted in grasses and rhizomatic MAPs. Based on demand and marketing opportunities for MAPs, farmers are advised to grow aromatic plants in large areas on a community basis to meet huge industrial demand and variety of medicinal crops in small areas to meet the requirement of traditional systems of medicine.  相似文献   

9.
Potassium phosphite for control of downy mildew of soybean   总被引：1，自引：0，他引：1  
Downy mildew of soybean, caused by Peronospora manshurica, is widely spread throughout Brazil. The objective of this study was to evaluate the use of potassium phosphite to control this disease. Field experiments were conducted during the growing season of 2006/2007 and 2007/2008 in the state of Parana in southern Brazil. The experimental design consisted of completely randomized blocks in a factorial arrangement (4 × 2) with four replications. Four rates of potassium phosphite (0, 375, 750 and 1500 g P2O5 + K2O ha−1) were applied at two growth stages, V6 (fifth trifoliolate leaf) and R2 (full flowering), followed by one or two applications of pyraclostrobin and epoxiconazole (66.5 + 25 g a.i. ha−1) at R3 (pod development) or R2 and R5.1 (10% of pod filling), mainly for the control of Asian soybean rust (Phakopsora pachyrhizi) and powdery mildew (Microsphaera diffusa). Field experiments were conducted to quantify the severity of downy mildew on leaves, nutrient content in leaf tissue (N, P and K), leaf area index (LAI), yield and seed weight. The maximum severity of downy mildew was observed at a growth stage of R5.3 (50% of pods were ripe), with 14% and 46% of the leaf area affected in 2006/2007 and 2007/2008, respectively. Also it was detected some effect of phosphite on Asian rust control but it was mostly in the trial of 2007/08 when the epidemic was very low (9.7-21.8% of severity). There was a linear reduction in the severity of downy mildew and a significant improvement in the LAI with an increase in the rate of phosphite applied. During the 2006/2007 growing season, a significant yield improvement was observed due to the application of the highest rate of phosphite. Two fungicide applications following phosphite application significantly improved the control of Asian soybean rust and powdery mildew, yield and seed weight when compared to a single fungicide application.  相似文献   

10.
The inhibitory properties of middle-viscosity Chitosan on the growth of fungus Ramularia cercosporelloides were studied in vitro. The inhibitory concentration that delayed 50% of the radial growth (IC50) was 3.4 g l−1 for middle-viscosity Chitosans with molecular weights of about 133 and 187 kDa (middle molecular weight) dissolved in lactic and acetic acids, respectively. At 96 h of incubation and under the same growing conditions, inhibitions of 91.79% and 73.13% of the radial growth of the fungus were observed when 3.4 g l−1 of Chitosan was dissolved in 0.05 M acetic and 0.05 M lactic acid, respectively. The biomass production was significantly lower than that observed in the controls at 72 h. Based on these in vitro results; Chitosan could be a good alternative to control the disease caused by R. cercosporelloides on safflower.  相似文献   

11.
The timing and pattern of mussel scale (Lepidosaphes ulmi (L.)) crawler emergence was monitored in relation to air and bark-surface temperatures using sticky band traps around branches in apple orchards in Kent, UK in three successive years, 2007-2009. The emergence and migration of the crawlers lasted for over 4 weeks at a high level, much longer than had been previously reported. In all three years, there were clearly two peaks of emergence of the crawlers, possibly because there is a diapausing and non-diapausing form of the insect. A temperature sum model developed in the 1990s in The Netherlands using air temperatures predicted the peak emergence of crawlers to within 5-16 days; however, the model was less accurate when tree bark temperatures for the north or south of the tree were used. We have developed two models to predict the emergence of the crawlers by revising the original Dutch model. The observed emergence period (5-95%) was longer than the predicted in all three years but the two revised models performed better than the original Dutch model.In two experiments, in 2007 and 2008, the efficacy of a wide range of insecticide products at different timings during crawler emergence was evaluated. Of the 7 products compared as single or two sprays (spray volume 500 l ha−1) at different emergence timings, or with the addition of adjuvants or as winter treatments, thiacloprid 480 g/l SC (375 ml ha−1) and acetamiprid 20% w/w SP (375 g ha−1) gave the best and similar control, reducing the percentage of fruits infested by 94%. Two sprays of fenoxycarb 25% w/w WG (600 g ha−1) gave the poorest control (28%). Two sprays of spirodiclofen 240 g/l SC (600 g ha−1), chlorpyrifos 75% w/w WG (960 g ha−1) or flonicamid 50% w/w WG (140 g ha−1) gave intermediate results, reducing the percentage infestation by 72% on average. Adjuvants gave no additional value to the treatments when applied in admixture and winter applications of mineral oil (spray volume 1000 l ha−1), alone or in admixture with chlorpyrifos or thiacloprid were not effective at controlling mussel scale the following growing season.Overall, acetamiprid and thiacloprid were the most efficacious insecticides and this study indicates that sprays are best applied in the latter part of the migration (after 50% emergence) with an interval between sprays of at least two weeks to span the long emergence period of the pest.  相似文献   

12.
The sweetpotato whitefly, Bemisia tabaci (Gennadius), has become a major threat to agriculture worldwide. The development of insecticide resistance in B. tabaci has necessitated the exploration of new management tactics. The toxicity of imidacloprid and buprofezin to various life stages of B. tabaci was determined in the laboratory. Also, the sublethal effects of both insecticides were studied on demographic and biological parameters of B. tabaci. Both insecticides were very toxic against first stage larvae of the pest with LC50 values of 1.0 and 19.3 ppm for buprofezin and imidacloprid, respectively. Toxicities decreased between successive stages (LC50 values ranging from 1.0 to 2854.0 ppm). The LC50 values of imidacloprid for adult males, females and eggs were 11.8, 71.6 and 151.0 ppm, respectively. Buprofezin had no significant effect on adults and eggs. The sublethal concentration of imidacloprid had no significant effect on demographic and biological parameters of B. tabaci but the maximal value for the mean generation time (T) (18.8 day) was observed in imidacloprid treatment. Buprofezin significantly decreased stable population and biological parameters of B. tabaci except it did not decrease the rate of population increase or the sex ratio of offspring.  相似文献   

13.
The efficacy of a new fungicide fluopicolide in suppression of Phytophthora blight caused by Phytophthora capsici was evaluated under laboratory and field conditions. Studies with 51 P. capsici isolates from vegetable crops in Georgia, USA, indicated that 5.9% of the isolates were resistant, 19.6% were intermediately sensitive, and 74.5% were sensitive to 100 μg ml−1 of mefenoxam based on in vitro mycelial growth. EC50 values of fluopicolide in inhibiting mycelial growth of 25 isolates, representing resistant, intermediately sensitive, and sensitive to mefenoxam, ranged from 0.05 to 0.35 μg ml−1 with an average of 0.2 μg ml−1 EC50 values of fluopicolide in suppressing zoospore germination and sporangium production of the 25 isolates ranged from 1.1 to 4.5 μg ml−1 and 0.3–9.0 μg ml−1, respectively. Evaluation of a collection of 150 P. capsici isolates from vegetables and irrigation ponds found none of the isolates were resistant to 10 μg ml−1 of fluopicolide. Field experiments were conducted to determine the efficacy and application methods of fluopicolide for control of P. capsici on squash in spring 2007 and 2009. Fluopicolide applied through drip irrigation or as a foliar spray at 86.6 or 115.4 g ha−1 consistently provided significant disease reduction and increased squash yield. Results with fluopicolide were similar or slightly superior to mefenoxam applied at recommended rate. Fluopicolide applied at 57.7 g ha−1 did not provide consistent satisfactory disease suppression. The results indicated that fluopicolide was effective in suppression of different stages of the life cycle of P. capsici and could be a viable alternative to mefenoxam for managing Phytophthora blight in squash production.  相似文献   

14.
为研究盐胁迫下小麦维持钾、钠平衡的生理机制,以耐盐小麦沧麦6005和盐敏感小麦矮抗58为材料,利用TEA、NEM、Ba(NO_3)_2三种药物分别抑制钾离子通道、钾载体及非选择性阳离子通道,测定正常及盐胁迫下小麦叶片K~+、Na~+含量,比较耐盐性不同的小麦品种在K~+、Na~+吸收中的差异。结果显示,盐胁迫下,沧麦6005和矮抗58叶片K~+含量下降,Na~+含量增加;沧麦6005叶片Na~+含量低于矮抗58,K~+/Na~+比值高于矮抗58。正常条件下,NEM、TEA处理均可降低沧麦6005和矮抗58叶片K~+含量,NEM处理较TEA处理效果更为明显;TEA处理显著降低了盐胁迫下矮抗58叶片K~+含量,而NEM处理则明显降低了盐胁迫下沧麦6005的叶片K~+含量;TEA、NEM、Ba(NO_3)_2处理降低了盐胁迫下矮抗58叶片Na~+含量,仅NEM处理降低了沧麦6005叶片Na~+含量。综上所述,正常条件下,钾载体是小麦K~+吸收的主要方式;盐胁迫下,耐盐品种和盐敏感品种K~+吸收途径不同,耐盐品种的NSCCs和钾离子通道具有更强的"拒钠"能力。  相似文献   

15.
Summary Different nitrogen sources (NO3 −, NH4 +, glutamic acid and their combinations) influenced the growth and morphogenic responses (node number, shoot length, and stem, leaf and root dry weight) of three micropropagated potato cultivars (Spunta, Kennebec, Huinkul). Addition of reduced nitrogen (NH4 + or glutamic acid) in a nitrate medium increased shoot length and leaf number. The large increase in growth in plants fed with NO3 −, NH4 + could be explained by higher organic nitrogen content and enhanced dry matter partition to the shoot. This suggests that reduced nitrogen source is required, at least as a supplement to NO3 −, to enhance N assimilation and growth.  相似文献   

16.
The population dynamics of Xanthomonas campestris pv. vitians (Xcv) was studied both externally and internally in lettuce, tomato and pepper plants. In addition, the application of bactericides during transplant production period was carried out for the management of bacterial leaf spot of lettuce under greenhouse conditions. Epiphytic populations of Xcv were recovered on leaves of lettuce plants (105 CFU/g) 5 weeks after sprayed than the other plant species when inoculated with 108 CFU/ml of Xcv. When plants of each crop species infiltrated with the bacterium at 105 CFU/ml, the highest populations were developed in lettuce (108 CFU/cm2) followed by pepper with 106 CFU/cm2 and tomato with 105 CFU/cm2 10-days after infiltration. Application of a mixture of Maneb and Kocide or Kocide alone as a foliar spray on lettuce significantly reduced the incidence and disease severity of bacterial leaf spot by 29 and 27% respectively. Spread of the bacterium and development of the disease may partly be managed by avoiding intercropping of these plants commonly grown in close proximity to lettuce. For the management of leaf-associated populations of Xcv in lettuce, use of a mixture of Maneb and Kocide is advocated to minimize the effect of attacks.  相似文献   

17.
Carbendazim, iprodione, prochloraz-Mn, thiabendazole and thiophanate-methyl were tested in vitro and in vivo for their effect on Mycogone perniciosa, the mycoparasite that causes wet bubble disease of white button mushroom. In vitro experiments showed that prochloraz-Mn (ED50 = 0.006–0.064 μg ml−1) and carbendazim (ED50 = 0.031–0.097 μg ml−1) were the most effective fungicides for inhibiting the mycelial growth of M. perniciosa, while iprodione (ED50 = 1.90–3.80 μg ml−1) was the least effective. The resistance factors calculated for the five fungicides were between 1.4 and 2. The results obtained suggest that there is very little risk that M. perniciosa will develop resistance to the fungicides assayed. The in vivo efficacy of fungicides for control of wet bubble was studied in two mushroom cropping experiments, which were artificially infected with two doses of M. perniciosa, 106 and 107 spores m−2, respectively. There was, in the low dose inoculum experiment, a very high degree of effectiveness (96.5–100.0%) with all the fungicides assayed. However, iprodione performed poorly (20.5–24.4%) compared with the other fungicides (88.7–100.0%) in the high concentration inoculum experiment. The most effective treatments for controlling wet bubble did not improve the biological efficiency of Agaricus bisporus.  相似文献   

18.
In maize, the effects of nitrogen (N) deficiencies on the determination of kernel number per plant (KNP) have been described only by changes in plant growth rate during the critical period for kernel set (PGRcp). We hypothesize that N availability affects KNP also through variations in biomass allocation to the ear, which determines a stable N concentration in this organ. Six maize hybrids of different breeding origin were evaluated in field experiments at two N levels (0 and 400 kg N ha−1 applied). Traits included were KNP and per apical ear (KNE1), and the allometric estimation of PGRcp, ear growth rate during the critical period (EGRcp), and N content and N concentration in different plant organs. We demonstrated that (i) N availability promoted differences among genotypes (G) in the response of EGRcp and KNP to PGRcp, (ii) variations in KNE1 were explained by EGRcp (r2 = 0.64) and by ear N content at silking + 12 d (r2 = 0.64), and (iii) ear N concentration was a highly conservative trait (range between 10.47 and 15.98 mg N g biomass−1) as compared to N concentration in vegetative tissues (range between 4.94 and 18.04 mg N g biomass−1). Three response patterns were detected among hybrids, one for which the relationship between EGRcp and PGRcp did not vary between N levels and experiments, a second one for which N availability affected this relationship, and a third one for which the response was affected by the year (Y) effect. These results, together with the high correlation between EGRcp and ear N content (r2 = 0.88), evidenced the importance of both photo-assimilate and N availability on EGRcp and KNP determination. Values of 1.5–2.3 g ear−1 d−1 during the critical period and 0.49–0.70 g of N ear−1 at silking + 12 d were determined as thresholds for maximizing KNE1, and both could be easily estimated by means of allometric models.  相似文献   

19.
Isothiocyanates (ITCs), a series of new nematicides of the -NCS group, were evaluated for their efficacy against root-knot nematode Meloidogyne javanica. Of the compounds tested, AllylITC, AcITC, EtITC, BzTC, BzITC, 1-PEITC and 2-PEITC showed in vitro irreversible nematicidal activity against second-stage juveniles of M. javanica, following exposure for 72 h at concentrations as low as 5 μg mL−1. When exposed to AllylITC, AcITC and EtITC at lower concentrations, motile juveniles also became irreversibly immobile in 3 days, with a LC50 value at 2.76, 2.53 and 3.05 μg mL−1, respectively. In the pot experiments, 1.0 ml AllylITC and 1.1 ml AcITC per kg of soil controlled M. javanica, similarly to or better than metam sodium at its recommended dose. Similar results were obtained in the field experiments using 1.0 kg AllylITC or 1.0 kg AcITC ha−1. Based on the results of this study, AllylITC and AcITC have potential to be used as new bio-fumigant nematicides.  相似文献   

20.
Several organic solvent extracts of Chenopodium ficifolium were tested for their insecticidal activity against melon and cotton aphid, Aphis gossypii, on cucumber plants. Both methanol and ethanol extracts, at 5000 μg ml−1, were highly active giving over 80% control. The other crude extracts displayed moderate or weak insecticidal activity giving control in the range of 16–69%. Two phospholipids were isolated as insecticidal active substances from C. ficifolium. Their chemical structures were identified as 1-palmitoyl-2-(3-trans)-hexadecenoyl-sn-glycero-3-phosphoglycerol and 1-palmitoyl-2-linoleoyl-3-glycerophosphocholine by GC–MS, EDS, mass and NMR spectral analyses. Both compounds displayed a dose-dependent mortality of A. gossypii. Furthermore, the liquid formulation that was obtained by partitioning with n-hexane from the methanol extract of C. ficifolium controlled melon and cotton aphid on cucumber plants effectively. These results indicate that extracts of C. ficifolium have potential for development as botanical insecticides for controlling A. gossypii infesting cucumber plants.  相似文献   

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