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1.
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   

2.
Requirements of consumers for products with low residues of pesticides have increased the need for alternative disease management practices. The concentration of boron in fruit affects its quality, shelf life and the development of physiological disorders. However, the effect of boron on the susceptibility of peach to fruit rots has not been reported. This study investigated the effect of boron (Power B and Borax) on the development of Monilinia laxa on peaches (cv Andross). Mycelial growth of M. laxa was inhibited on potato dextrose agar supplemented with 750 μg ml−1 of Borax or 1000 μg ml−1 of Power B. The EC 50 values were 107.9 and 522.4 for Borax and Power B respectively. Field investigations showed that the incidence of peach infections by M. laxa was negatively correlated with the content of Boron in the leaves. Post-harvest dipping of peaches in Power B or Borax solution, at concentrations recommended by manufacturer (2 μg ml−1 for Power B and 1 mg ml−1 for Borax), significantly reduced the development of M. laxa. Power B, at rates of 6 μg ml−1, and Borax at rates of 3 mg ml−1 were the most effective in reducing infections by M. laxa. Finally, post-harvest dipping of fruit in Power B or Borax reduced losses of fruit weight and improved fruit firmness one month after storage, showing that boron increased the maintainability of peaches in cold storage. Peaches treated with 6 μg ml−1 Power B or 3 mg ml−1 Borax had the highest flesh firmness and the lowest water losses, while untreated control peaches were the least firm. Generally, Borax was significantly less effective than Power B, but better than the control treatment.  相似文献   

3.
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   

4.
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   

5.
Castilleja tenuiflora is a highly valued medicinal plant that grows in pine-oak woods in Mexico. In this study, we identified for the first time verbascoside and isoverbascoside as the major phenylethanoid glycosides (PhGs) in C. tenuiflora. These compounds have proven biological activities, including anti-inflammatory, antioxidant, and cytotoxic activities, which may be related to the traditional uses of this plant. We developed a reverse-phase high-performance liquid chromatography (RP-HPLC) procedure to analyze PhGs, and determined their concentrations in various different tissues of wild plants. Verbascoside accumulated mainly in roots and inflorescences (9.23 and 7.88 mg g−1 dry biomass, respectively), while isoverbascoside accumulated mainly in the roots (7.13 mg g−1 dry biomass). To provide an alternative source of material for production of bioactive compounds, we established in vitro adventitious root cultures in which roots were grown in B5 medium containing either 10 μM indole 3-acetic acid (IAA) or 10 μM α-naphthaleneacetic acid (NAA). The greatest dry biomass yield (30 g L−1) was achieved at 30 days after transfer of roots into IAA-containing medium. The highest specific yields of PhGs were also obtained using this auxin; the maximum level of verbascoside was 14.62 mg g−1 dry root biomass (438.6 mg L−1) at 30 days after root transfer, and the maximum yield of isoverbascoside was 37.32 mg g−1 dry root biomass (522.48 mg L−1) at 23 days after root transfer. Adventitious root cultures of C. tenuiflora are a promising system for further studies on scale-up and phenylethanoid glycosides biosynthesis.  相似文献   

6.
The effects of extracts of different parts of the perennial tropical plant Balanites aegyptiaca (L) Del., including various solvent extracts of roots, methanol extracts from leaves, fruits, flowers and roots, partially purified saponins obtained from its roots and a standard saponin were studied on the life cycle (adult longevity, number of eggs, crawlers, adults, weight of adults and % wax content) of a laboratory-reared parthenogenic line of the mealy bug, Maconellicoccus hirsutus (Homoptera: Pseudococcidae). Extracts derived from various parts of B. aegyptiaca (leaves, fruits, flowers, and roots in methanol) affected the life cycle of M. hirsutus with a methanol root extract being the most effective at a concentration of 500 μg ml−1. Partially purified saponin of B. aegyptiaca and the commercial bark saponin extract (Sigma) from Quillaja saponaria at a concentration of 500 μg ml−1 were effective in reducing the longevity of M. hirsutus. Significant reductions in oviposition by M. hirsutus were found for all the extracts at a concentration of 500 μg ml−1. Extracts also affected the number of emerging crawlers, number of adults as well as the weight and wax content of emerging adults. These studies suggest that B. aegyptiaca plant extracts and saponins can be useful botanical insecticides for the protection of crops from mealy bugs.  相似文献   

7.
Nitrogen fertilization is one of the factors that influences Bemisia tabaci (Gennadius) population density. The aim of this study was to determine the effects of three N application rates (75, 205 and 335 mg/l) and three ratios of NO3−:NH4+ ions (92:8, 75:25 and 55:45) in standard nutrient solution (205 mg/l N) on the population density of B. tabaci. The experiments were conducted on spring-summer hydroponic crops of tomato. The effect of plant stratum on the whitefly population was also determined. The aggregation of B. tabaci adults as well as their oviposition rate was higher at 205 and 335 mg/l N than on plants grown at 75 mg/l N. By the end of the experiment (60 d after infestation), the number of nymphs on plants at 205 mg/l N was higher than on plants at 75 mg/l N. The number of pupae was lowest on plants supplied with 75 mg/l N. An increase in NH4+ percentage in standard nutrient solution (from 25% to 45% of the total N) reduced adult population density and oviposition rate. The density of nymphs and pupae, at 60 d after infestation, was lower on the tomato plants grown at 75:25 and 55:45 NO3−:NH4+ ratios compared to the 92:8 ratio. The 75:25 and 55:45 NO3−:NH4+ ratios resulted in a higher incidence of blossom-end rot of tomato fruit, with a lower incidence of disorder at 75:25 than at the 55:45 ratio. Plant stratum influenced adult whitefly distribution in two years of the study. Middle stratum leaves were more attractive to adults in both years. The results demonstrate the effects of N fertilization (N rate and the ratio of NO3−:NH4+) and plant stratum on B. tabaci population density.  相似文献   

8.
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   

9.
Some secondary metabolites of plants function as antimicrobial products against phytopathogens and constitute an increasingly important class of pesticides. In the present study, the essential oil of Asarum heterotropoides var. mandshuricum was analyzed by GC/MS and its antimicrobial activity was evaluated against five phytopathogenic fungi. Major components of the oil were methyleugenol (59.42%), eucarvone (24.10%), 5-allyl-1,2,3-trimethoxybenzene (5.72%), and 3,7,7-trimethylbicyclo(4.1.0)hept-3-ene (4.93%). The essential oil and the most abundant component, methyleugenol, were separately assayed for inhibition of 5 pathogens: Alternaria humicola, Colletotrichum gloeosporioides, Rhizoctonia solani, Phytophthora cactorum and Fusarium solani. Both the oil and methyleugenol strongly inhibited the growth of the test pathogens (IC50 values <0.42 μg ml−1) except F. solani, with the best activity against P. cactorum (IC50 values = 0.073 and 0.052 μg ml−1, respectively). It is concluded that the essential oil of A. heterotropoides var. mandshuricum has a broad antiphytopathogenic spectrum, and that methyleugenol is largely responsible for the bioactivity of the oil. The mode of action of methyleugenol against P. cactorum is discussed based on changes in the mycelial ultrastructure.  相似文献   

10.
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   

11.
The essential oils from 9 aromatic plants were tested on repellency and mortality of Meligethes aeneus adults. All the tested essential oils caused high mortality of M. aeneus adults in the tarsal tests. The lethal doses after 6 h exposure were ranged between 197 and 1508 μg cm−2. Essential oils obtained from Carum carvi and Thymus vulgaris were most efficient where LD50 was estimated as 197 and 250 μg cm−2, respectively.Repellency declined in all the essential oils as a function of time. The longest persistence time was determined for essences obtained from C. carvi and T. vulgaris where significantly the highest repellent index of 65.6% and 63.8%, respectively, was determined. Repellent index lower than 15% was determined for the remaining essential oils.  相似文献   

12.
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   

13.
Antifungal substances from a methanol extract of Cirsium japonicum roots were purified and characterized, and their antifungal activities against various plant pathogens were evaluated. Three polyacetylene substances were isolated from roots of C. japonicum using repeated column chromatography; these were identified as ciryneol A, ciryneol C and 1-heptadecene-11,13-diyne-8,9,10-triol by mass and nuclear magnetic resonance spectral analyses. In vitro antifungal activity of the three substances varied according to compound and target species. Magnaporthe oryzae, Colletotrichum coccodes, Colletotrichum acutatum, Pythium ultimum and Botrytis cinerea were relatively sensitive to the three polyacetylenes, with IC50 values below 50 μg mL−1. In vivo, they all showed similar and broad antifungal spectra against the seven plant diseases tested. At 500 μg mL−1, all three compounds effectively suppressed the development of rice blast, rice sheath blight, tomato late blight, wheat leaf rust and red pepper anthracnose, with control values over 90%. They were highly active especially against wheat leaf rust; they controlled the development of this disease more than 88% even at a concentration of 125 μg mL−1. In addition, ciryneol C effectively suppressed barley powdery mildew. This is the first report on the antifungal activities of the three polyacetylenes from roots of C. japonicum against plant pathogenic fungi. Polyacetylenes from roots of C. japonicum may contribute to the development of environmentally safer alternatives to protect crops from various phytopathogenic fungi.  相似文献   

14.
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   

15.
Mesembryanthemum edule L. (sourfig, Aizoaceae) has long been used as food and in traditional medicine. This study was intended to characterize the antioxidant properties and the phenolic compounds of M. edule leaf, stem and root. The approach consisted to evaluate these organs for their antioxidant activities through several in vitro tests, to determine tissue contents in total phenolics, flavonoids and proanthocyanidins and to establish the phenolic composition through RP-HPLC analysis. All studied organs showed a high antioxidant activity as compared to positive control BHT, with maximal efficiency for stems followed by leaves and roots. The highest polyphenolic levels were found in stems and leaves (86.5 and 68.7 mg GAE g−1 DW, respectively), suggesting that their strong antioxidant activity could be attributed to these phytochemicals. The HPLC analysis revealed that the main phenolic compounds were quercitrin and avicularin (1.4 and 1.15 mg g−1 DW, respectively) in the leaves, while catechin and procyanidin B2 (1.66 and 1.54 mg g−1 DW, respectively) were the most abundant phenolics in the stems. Overall, the strong antioxidant activity and richness of M. edule aerial tissues suggest that it could be advantageously used as a functional or nutraceutical food, to prevent or moderate oxidative stress-related diseases.  相似文献   

16.
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   

17.
In separate experiments conducted in 2007 and 2008, growth and accumulation of selected caffeic acid derivatives (CADs; i.e., caftaric acid, chlorogenic acid, echinacoside, caffeic acid, cynarin, p-coumaric acid, ferulic acid and cichoric acid) were determined in Echinacea angustifolia DC. var. angustifolia seedlings grown in hydroponic culture (floating raft system) at a density of 122 plant m−2 (at planting). Plants were harvested 11 (2007) or 16 (2008) weeks after transplanting (i.e., 15 or 20 weeks after sowing). In both years, plants grew vigorously and at harvest approximately half of the plants under observation had developed one to three inflorescences. In 2008, the root yield (2940 kg ha−1) harvested in nearly eight months from two consecutive hydroponic cultures was within the yield reported in the literature for field cultivations lasting two to four years. None of the selected CADs was found in the leaves, while the inflorescences (stem and capitulum) contained only caftaric acid and echinacoside at concentrations higher than the detection limits (0.05 mg g−1 dry weight). Echinacoside, cynarin and chlorogenic acid were found in root tissues at concentrations ranging from 0.36 to 5.25 mg g−1 dry weight. In all plant samples, echinacoside, which is the marker compound for E. angustifolia material, did not reach the minimum quality standard (10 mg g−1 dry weight) for the production of standardized extract. We concluded that short-cycle, high-density greenhouse hydroponic culture stimulates plant growth and root production in E. angustifolia, but it does not ensure sufficient CADs accumulation in dried roots.  相似文献   

18.
Wild oat (Avena fatua L.) is the most troublesome weed in cereal crops in Argentina. With the aim of studying the effects of different herbicides, doses, and wild oat growth stage at application on weed control and crop yield, field experiments were conducted in wheat and barley crops during three growing seasons in the south of Buenos Aires Province, Argentina. Treatments were post-emergence applications of new herbicide, pinoxaden + cloquintocet mexyl (5%-1.25%), at doses that ranged from 20 g to 60 g a.i. pinoxaden ha−1, applied at two to three leaves and the beginning of tillering of wild oat. In addition, standard treatments were included and applied at the same wild oat growth stages. Diclofop methyl at 511 g a.i. ha−1 and fenoxaprop-p-ethyl at 55 g a.i. ha−1 were applied in barley. In wheat, diclofop methyl was replaced by clodinafop-propargyl + cloquintocet mexyl (24%-6%) at 36 g a.i. clodinafop-propargyl + 9 g cloquintocet mexyl ha−1 and in 2008/09 wheat experiments, iodosulfuron plus metsulfuron methyl (5%-60%) at 3.75 g a.i. ha−1 + 3 g a.i. ha−1 also was included. In both crops, pinoxaden at 30 g a.i. ha−1 and at higher rates, fenoxaprop-p-ethyl and clodinafop-propargyl gave the best control of wild oat. In 2006/07 wheat crops, treatments applied at tiller initiation provided better control than the early timing averaged across herbicides. However, wheat yield generally was greater with early application. In barley, wild oat control and crop yield were similar regarding time of application. Variations in crop yield were correlated with grain number m−2 both in wheat and barley, but relationships between both grain number and spikes m−2 and with grains per spike were identified only in wheat.  相似文献   

19.
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   

20.
Measurement of biochemical markers allows the quantification of wheat (Triticum spp.) grain tissue proportions in milling fractions. In order to evaluate the ability of extending this methodology to an unknown wheat grain batch, the variability of the markers in the different tissues was assessed on various wheat cultivars. Ferulic acid trimer amounts in the outer pericarp ranged from 0.97 to 1.67 μg mg−1 (dm) with an average value equal to 1.31 μg mg−1 (dm). Alkylresorcinols amounts in a composite layer, including the testa, the inner pericarp and the nucellar epidermis, ranged from 10.5 to 16.7 mg g−1 (dm), with an average value equal to 14.0 mg g−1 (dm). In the aleurone layer, phytic acid amounts ranged from 94.9 to 187.2 mg g−1 (dm) with an average value equal to 152 mg g−1 (dm) whereas, para-coumaric acid ranged from 0.08 to 0.29 μg mg−1 with an average level of 0.18 μg mg−1. In the embryonic axis, wheat germ agglutinin ranged from 879 μg g−1 to 2086 μg g−1 with an average value of 1487 μg g−1. The impact of this variability on tissue proportion determination was evaluated and a strategy to decrease the prediction error was suggested. Percentages of the outer pericarp, intermediate layer (including the testa), aleurone layer and embryonic axis within grains were calculated and their variability discussed.  相似文献   

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