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1.
Tobacco black shank caused by Phytophthora parasitica is a devastating soil-borne disease of tobacco in China. Control of tobacco black shank relies on numerous fungicide applications. A new carboxylic acid amide (CAA) fungicide, mandipropamid, was examined for its effects on various asexual developmental stages of P. parasitica in vitro and in tobacco seedlings. Although mandipropamid did not affect discharge of zoospores from sporangia, it strongly inhibited mycelial growth (mean EC50 value of 0.0112 μg ml−1), sporangia production (mean EC50 value of 0.009 μg ml−1), germination of encysted zoospores (mean EC50 value of 0.014 μg ml−1), and germination of sporangia (mean EC50 value of 0.017 μg ml−1). For protective activity in tobacco seedlings, various applications of mandipropamid were superior in reducing black shank compared to that of metalaxyl and of azoxystrobin; while for curative activity assay, 100 μg ml−1 of mandipropamid exhibited the same efficacy as that of metalaxyl, and presented superior activity than that of azoxystrobin. In 2010 and 2011, 119 isolates of P. parasitica from Guizhou Province of China were characterized for the baseline sensitivity to mandipropamid by measuring mycelial growth. Values of effective concentrations for 50% mycelia growth inhibition varied from 0.0068 to 0.0285 μg ml−1 and averaged 0.013 (±0.0045) μg ml−1, with a unimodal distribution. This information will serve as a baseline for tracking future changes in sensitivities of P. parasitica populations to mandipropamid in China. 相似文献
2.
Cis- and trans-protopinium,a novel nematicide,for the eco-friendly management of root-knot nematodes
Plant-derived nematicides are being increasingly used while select synthetic nematicides are phased out for environmental concerns. This is the first report on the in vitro nematicidal activity of cis- and trans-protopinium isolated from roots of Fumaria parviflora and its in vivo effect on the southern root-knot nematode Meloidogyne incognita. Cis- and trans-protopinium was isolated from the methanolic fraction FM2.1, and its structure elucidated using 13C and 1H nuclear magnetic resonance (NMR). The NMR spectra were characterized using deuterated dimethyl sulfoxide (DMSO) at temperatures of 25 and 80 °C. In an in vitro study, over 120 h of incubation, the area under cumulative percent hatch inhibition and mortality of cis- and trans-protopinium reached 100% at a concentration of 200 μg mL−1. In the greenhouse and field settings, cis- and trans-protopinium was evaluated against M. incognita on tomato at a concentration of 100, 200, and 300 μg mL−1 for two consecutive seasons, that is, spring and autumn, in 2010. At a concentration of 300 μg mL−1 in the greenhouse and field trials during spring and autumn, cis- and trans-protopinium significantly reduced the nematode galling index, the number of females per gram of root, and the reproduction factor, as well as increased plant height, fresh and dry shoot weights, and root length. Therefore, cis- and trans-protopinium can be used as an effective and safe nematicide against M. incognita on tomato in an organic and sustainable agricultural production system. Phytochemicals have various agricultural applications, especially to control economically important nematode pests. 相似文献
3.
The present study aimed to determine the in vitro and in vivo effects of Ziziphora clinopodioides Lam. essential oil (ZCEO) against Sclerotinia sclerotiorum on rapeseed plants. Gas chromatography-mass spectrometry (GC-MS) detected 21 compounds that represented 98.3% of the total amount of extracted oil, which mainly comprised pulegone (53.5%), isomenthone (10.4%), and carvone (5.7%). The mycelial growth of S. sclerotiorum was completely inhibited at essential oil concentrations of 1.25 and 0.15 μl ml−1 under contact and vapor phase conditions, respectively. Under contact phase, the germination of sclerotial was inhibited at the concentration of 1.00 μl ml−1. The essential oil concentration of 0.15 μl ml−1 in the vapor phase showed a strong inhibitory effect on sclerotial germination. Sclerotinia sclerotiorum growth on detached rapeseed leaves and potted rapeseed plants were dose dependently inhibited by the essential oil. Considerable morphological changes were also observed in the fungal hyphae and sclerotia. Both in vitro and in vivo results indicated ZCEO can effectively inhibit the growth of S. sclerotiorum. Thus, ZCEO could be used for crop protection. 相似文献
4.
Fluopicolide and pyraclostrobin were new systemic fungicides with highly inhibitory activity on a broad spectrum of oomycetes, but so far the fungitoxicity of their mixtures on the different developmental stages of Phytophthora infestans and whether synergism exists have not been investigated. The joint-toxicity of the mixtures of fluopicolide with pyraclostrobin was determined against the different developmental stages (mycelial growth, zoospore release, cystospore germination and sporangial germination) of P. infestans and late blight on the leaf discs and the potted plants of potato, and whether the synergistic interaction exists in the mixtures of the two fungicides were evaluated in vitro and in vivo based on the synergistic ratios calculated with the Wadley formulas. The protective activity and curative activity against P. infestans and the efficacy duration in controlling potato late blight of the synergistic mixtures of the two fungicides were examined in this study. The results showed that mixtures of fluopicolide (F) and pyraclostrobin (P) at the ratios of 10:1 and 1:4 (F:P) exhibited synergistic interactions and had excellent inhibitory activity against almost all developmental stages of P. infestans. Synergistic interactions of the mixtures at the ratios of 1:4 and 10:1 (F:P) against the mycelial growth of metalaxyl-resistant isolates were more obvious than against the mycelial growth of metalaxyl-sensitive isolates. Synergistic interactions of the mixtures at the ratio of 1:4 (F:P) against the mycelial growth of the most of the tested isolates were more obvious than those of the mixtures at the ratio of 10:1 (F:P). The highest activity of the mixtures was observed against zoospore release at the ratio of 1:4 (F:P) with EC50 value of 0.0044 μg ml−1. The strongest synergistic interaction of the mixtures was observed against zoospore release at the ratio of 10:1 (F:P) with the synergistic ratio of 5.27. The mixtures of fluopicolide and pyraclostrobin at the ratios of 1:4 and 10:1 (F:P) showed synergistic interactions against P. infestans on the leaf discs and intact plants of potato. The EC50 values for protective activity and curative activity of the mixture at the ratio of 10:1 (F:P) were 0.63 μg ml−1 and 0.87 μg ml−1, and EC50 values of protective activity and curative activity of the mixture at the ratio of 1:4 (F:P) were 0.27 μg ml−1 and 0.44 μg ml−1, respectively. At 14 days after spraying of fungicide solutions, the disease control efficacy of the mixtures at the ratios of 10:1 and 1:4 (F:P) was still over 80% at the dosages of 50 μg ml−1 and 100 μg ml−1, and the disease control efficacy of the two mixtures remained at about 97% at the dosages of 200 μg ml−1, indicating long-lasting effective control efficacy of the two fungicides against potato late blight. 相似文献
5.
Fenhexamid is a hydroxyanilide fungicide with excellent performance against Botrytis cinerea but also effective against Monilinia spp. which cause brown rot disease in apple and stone fruit. A total of 75 Monilinia laxa field isolates were utilized to determine baseline sensitivity while a number of fenhexamid-resistant laboratory mutants were used to evaluate the resistance risk associated with the longevity of the effectiveness of fenhexamid. Fenhexamid was found to be highly effective against all field isolates. EC50 values ranged from 0.02 to 1 μg mL−1 and were distributed unimodaly around an average of 0.1 μg mL−1. M. laxa laboratory strains with moderate and high resistance levels to fenhexamid were isolated after UV mutagenesis. All fenhexamid-resistant strains showed parental sensitivity to carbendazim, iprodione, fludioxonil, pyraclostrobin, flusilazole and prochloraz. Interestingly, some of the mutant strains were also resistant to tridemorph, fenpropimorph and spiroxamine. Studies on fitness parameters of fenhexamid-resistant strains revealed a fitness cost on sporulation and pathogenicity but not on mycelial growth. These results suggest that fenhexamid should be a good alternative site-specific fungicide for the control of brown rot disease caused by M. laxa. However, appropriate anti-resistance strategies should be considered to ensure the successful commercial use of fenhexamid in the long run. 相似文献
6.
Cercospora beticola, causal agent of Cercospora leaf spot (CLS) of sugar beet, is primarily controlled by fungicides. Benzimidazole and demethylation inhibiting fungicides, including carbendazim and flutriafol, have been widely used in Serbia. Since these fungicide groups have a site-specific mode of action, there is a high risk for developing resistance in target organisms, which is the most important limiting factor in Cercospora leaf spot chemical control. A rapid identification of flutriafol and carbendazim resistance can help researchers in examining the potential of different fungicide resistance management practices, as well as in selection of fungicides for use in the areas where resistance has occurred. One hundred single-conidia isolates were collected from 70 representative locations of the sugar beet production region in Serbia. Evaluation of the isolates' sensitivity was based on the reduction of mycelial growth on medium amended with 1.25 μg mL−1 flutriafol and 5 μg mL−1 carbendazim. Resistance to flutriafol and carbendazim was detected in 16% and 96% of the tested isolates, respectively. All isolates resistant to flutriafol were resistant to carbendazim as well, which is the first report of a double resistance to fungicides in C. beticola. Detection of the isolates resistant to flutriafol and carbendazim using Cleaved Amplified Polymorphic Sequence (CAPS) markers confirmed the results of the in vitro tests. The efficacy of carbendazim, flutriafol, azoxystrobin, and tetraconazole at commercially recommended doses was evaluated in field trials where sugar beet plants in plots were inoculated with a mixture of isolates either sensitive and/or resistant to flutriafol and carbendazim. Carbendazim and flutriafol efficacy was very low in plots inoculated with isolates resistant to these fungicides. Presented results will contribute to development of a pathogen population sensitivity monitoring strategy that could be used for an effective CLS management in the region. 相似文献
7.
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
8.
Development of cross resistance or multiple cross resistance in Phalaris minor in wheat will continue to increase, as the weed develops mechanisms of resistance against new herbicides. This weed is a major threat to wheat productivity in north-western India, and as such needs to be addressed with integrated weed management approaches, including crop and herbicide rotations, herbicide combinations along with cultural and mechanical methods. Three field experiments were conducted during 2008–09 to 2012–13 along with large plot adaptive trials during 2012–13 with the objective to evaluate the efficacy of sequential applications of pendimethalin applied pre-emergent followed by clodinafop, sulfosulfuron, or pinoxaden applied post-emergent and tank-mix applications of metribuzin with these post-emergence herbicides for the management of herbicide-resistant P. minor in wheat. Clodinafop 60 g ha−1 or sulfosulfuron 25 g ha−1 at 35 days after sowing (DAS) and pendimethalin 1000 g ha−1 as pre-emergence did not provide consistently effective control of P. minor in wheat. An increase in the dose of clodinafop from 60 to 75 g ha−1 and of sulfosulfuron from 25 to 30 g ha−1 also did not improve their efficacy to a satisfactory level. However, pinoxaden 50 g ha−1 provided effective control (97–100%) of P. minor but not of broadleaf weeds. The tank-mix application of metribuzin with clodinafop 60 g ha−1 or sulfosulfuron 25 g ha−1 at 35 DAS and the sequential application of pendimethalin 1000 g ha−1 or trifluralin 1000 g ha−1 just after sowing followed by clodinafop 60 g ha−1 or sulfosulfuron 25 g ha−1 at 35 DAS provided 90–100% control of P. minor along with broadleaf weeds in wheat, thus resulting in improved grain yields (4.72–5.75 t ha−1) when compared to clodinafop 60 g ha−1 (3.85–5.60 t ha−1) or sulfosulfuron 25 g ha−1 alone (3.95–5.10 t ha−1). The efficacy of mesosulfuron + iodosulfuron (a commercial mixture) 14.4 g ha−1 against P. minor was not consistent across the experiments and over the years. The ready-mix combination of fenoxaprop + metribuzin (100 + 175 g ha−1) at 35 DAS provided effective control of weeds but its varietal sensitivity needs to be determined before its use in field conditions. The tank-mix or sequential application of herbicides would be a better option than their applications alone to manage the serious problem of herbicide-resistant P. minor in wheat. 相似文献
9.
Tea gray blight, caused by the fungus Pestalotiopsis theae, is one of the most destructive diseases in tea plants. In this study, we evaluated the individual and synergistic antifungal activities of tea saponin (TS) and mancozeb against P. theae, as well as the mechanisms underlying their activity. The results indicated that TS significantly inhibited both the mycelial growth of P. theae, at an EC50 value of 1.03 mg mL−1, and its spore germination, at an EC50 value of 3.68 mg mL−1. TS also significantly enhanced the antifungal activity of mancozeb, and the cotoxicity factor (CTF) assays revealed that there was a synergistic interaction between TP and mancozeb (3:7) against mycelial growth and spore germination, with CTC values exceeding 100. Our results also revealed that TS and mancozeb treatments damaged the cell membranes of P. theae, leading to a significant leakage of soluble protein, reduction of sugar and induction of a significant increase of chitinase activity in the mycelial cells; the combination treatment significantly enhanced the observed damage, leakage and induction. These findings suggested that TS had antifungal activity and a synergistic effect with mancozeb and that the mechanism of this activity might be membrane damage and the consequent cytoplasm leakage. 相似文献
10.
Hua Wu Chao-Jun WangXiao-Wei Bian Shui-Yun ZengKai-Chun Lin Bo WuGuo-An Zhang Xing Zhang 《Crop Protection》2011,30(1):33-37
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.
Oxathiapiprolin is a new fungicide active against oomycetes. In vitro assays and field studies were conducted to examine the effect of oxathiapiprolin on Phytophthora nicotianae (Pn), the causal agent of black shank. The efficacy of oxathiapiprolin on mycelial growth, sporangia production, zoospore motility, and zoospore germination was assessed with four Pn isolates. EC50 values were low ranging from 0.0039 to 0.0049 μg a.i./mL for mycelial growth, 0.00052–0.00081 μg a.i./mL for sporangia production, 0.0035–0.0051 μg a.i./mL for encysted zoospore germination, and 0.0055–0.0166 μg a.i./mL for zoospore motility. Sixty six Pn isolates, 60 from tobacco and six from ornamental plants were examined for sensitivity to oxathiapiprolin at 1 μg a.i./mL. Mycelial growth at 1 μg a.i./mL was observed in only one isolate from tobacco whereas the six Pn isolates from ornamental plants five of which were resistant to mefenoxam at 100 μg a.i./mL, were found to be sensitive to oxathiapiprolin. The efficacy of oxathiapiprolin against black shank was assessed in three field studies in North Carolina. Treatments of oxathiapiprolin were equal or superior to mefenoxam against black shank in each field study. Our results suggest that oxathiapiprolin is a highly efficacious fungicide against P. nicotianae, and will be a useful tool in controlling black shank of tobacco. 相似文献
12.
Hemant J. Patil Alok K. SrivastavaDhananjaya P. Singh Bhushan L. ChaudhariDilip K. Arora 《Crop Protection》2011,30(10):1269-1273
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
13.
Mango malformation disease (MMD) caused by Fusarium mangiferae severely affects the crop and is widely distributed in almost all mango-growing regions worldwide. Since malformed inflorescences do not bear fruit, MMD is a major constraint to crop production in affected areas. No effective management methods have been reported to date. The airborne nature of dissemination and infection of buds suggest that protection of buds from infection when inoculum prevails may be a plausible method for disease control from season to season. Various fungicides were assessed for their ability to control the pathogen under laboratory, greenhouse and field conditions. Prochloraz was the most effective fungicide in inhibiting F. mangiferae in vitro with a 0.01 μg mL−1 concentration required for 50% fungal growth inhibition. In greenhouse trials, protective and curative activity exceeding 90% was achieved when the fungicide was applied up to 14 days prior or post inoculation. Field experiments conducted over a number of seasons in different regions in Israel indicate that combined sanitation with timely applications of prochloraz resulted in a significant reduction in MMD disease severity and incidence, as well as a significant increase in yield in treated plots. It is assumed that long-term treatment by removal of infected panicles (the main source of inoculum) combined with timely sprays will result in disease reduction annually achieving negligible levels of malformation in treated orchards, in time. 相似文献
14.
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
15.
The objectives of this study were to investigate the mechanisms of action and to evaluate the potential application of Desmos chinensis extracts for controlling rice sheath blight. The dichloromethane extract from D. chinensis demonstrated high antifungal activity against Rhizoctonia solani. The extract was shown to have anti-R. solani activity with minimum inhibitory concentration (MIC) and minimum fungicidal concentration values ranging from 31.2 to 62.5 μg mL−1 and from 62.5 to 500 μg mL−1, respectively. Bioautography on thin-layer chromatography plates demonstrated antifungal activity of the extract with an Rf value of 0.33. A total of 7 compounds, 2 benzoate esters (benzyl benzoate and benzyl 2-hydroxybenzoate), 2 sesquiterpenoids (α-eudesmol and β-eudesmol), 1 aromatic alcohol (benzyl alcohol), 1 aromatic ketone (acetophenone) and 1 diterpenoid (phytol), were detected and identified using gas chromatography–mass spectrometry analysis. Electron micrographs confirmed the effects of the extract on morphological and ultrastructural alterations in the treated fungal cells. The micrographs of the mycelia treated with the extract at 4MIC illustrated aberrant morphology such as shrinkage, partial distortion and globular structures of different sizes along the surface of the mycelia. Damaging membranous structures including disruption of the cell membrane, partial loss of nuclear membranes, and depletion of hyphal cytoplasm and membranous organelles were observed. Foliar application of D. chinensis extract at a concentration of 2 mg mL−1 on rice markedly decreased sheath blight severity. It was concluded that the application of D. chinensis extract can be used as a botanical fungicide to control rice sheath blight. 相似文献
16.
The effect of chitosan treatment alone or in combination with methyl jasmonate (MeJA) against Alternaria alternata in vitro and in vivo, and defense related enzyme activities were investigated. 100–500 μl/l MeJA significantly inhibited mycelial growth of A. alternata. The inhibitory activity of MeJA on mycelial growth, spore production, spore germination and germ tube length of A. alternata in vitro could be enhanced by 0.1% chitosan. The combination of 0.1% chitosan and 500 μl/l methyl jasmonate was more effective to reduce the disease incidence and lesion diameter of postharvest decay of cherry tomato than the application of MeJA or chitosan alone. The combined treatments resulted in higher activities of PPO (polyphenol oxidase), POD (peroxidase) and PAL (phenylalanine ammonialyase) than the control. This work indicated that the combination of chitosan and methyl jasmonate is a promising method to control postharvest decays of fruit and vegetables. 相似文献
17.
Zheng-He TangYi-Ping Hou Si-Ping ZhangJian-Xin Wang Ming-guo Zhou 《Crop Protection》2011,30(3):354-359
Litchi downy blight caused by Peronophythora litchii is a devastating disease of litchi plants in China. Control of litchi downy blight requires numerous fungicide applications. A new carboxylic acid amide (CAA) fungicide, mandipropamid, was examined for its in vitro effects on multiple asexual stages of four single-sporangium P. litchii isolates and protective activity against downy blight in detached fruit assays. Though mandipropamid did not affect discharge of zoospores from sporangia, it strongly inhibited mycelial growth (mean EC50 = 0.0048 μg ml−1), sporangia production (mean EC50 = 0.0032 μg ml−1), germination of encysted zoospores (mean EC50 = 0.0023 μg ml−1), and germination of sporangia (mean EC50 = 0.0061 μg ml−1). On detached fruit, 0.39, 1.56 and 6.25 μg ml−1 of mandipropamid were superior in reducing downy blight compared to metalaxyl and flumorph, however, the 25 μg ml−1 application rate was necessary for all three CAA fungicides to completely inhibit the disease. In 2007, 100 isolates from Fujian, Guangdong, and Guangxi Provinces of China were characterized for the baseline sensitivity to mandipropamid. The isolates obtained from different provinces showed similar baseline sensitivities to mandipropamid. Baseline sensitivities formed a unimodal curve with mean EC50 values of 0.0055 ± 0.0012 μg ml−1 for inhibition of mycelial growth. The described baseline sensitivities of P. litchii populations will be useful for monitoring possible shifts in sensitivity to mandipropamid. 相似文献
18.
The aims of the present study were to compare arabinoxylan, glucomannan, arabinogalactan, dietary fibre and mineral contents of fibre rich and enriched-fibre rich fractions (FRF, E-FRF) obtained by two milling systems from biofortified (+) and non-biofortified (−) hull-less barley cultivar, Yalin and determine impact of biofortification (Zn, I, Se).Arabinoxylan contents and recoveries of FRF obtained by roller mill (FRFR) were 6.52% and 6.70%; 82.6% and 83.3% while those of FRF obtained by hammer mill (FRFH) were 7.36% and 7.24%; 73.9% and 73.5% for Yalin (−) and Yalin (+), respectively. Likewise, arabinoxylan contents and recoveries of E-FRFR were 11.91, 11.66%; 70.8% and 67.2% while those of E-FRFH were 11.70%, 12.13%; 61.3% and 64.9% for Yalin (−) and Yalin (+), respectively.Arabinogalactan contents of E-FRFR and E-FRFH were comparable (1.32–1.45%) for both Yalin samples. Their glucomannan contents were higher than arabinogalactan contents (1.79–1.90%). Furthermore, total dietary fibre contents of E-FRFR and E-FRFH were determined as 2.4–2.7 fold higher than their whole grain Yalin samples. Zinc, iodine, selenium contents (22 mg kg−1, 16 μg kg−1, 122 μg kg−1) of the whole grain of Yalin (−) increased through biofortification and milling and reached to 59 mg kg−1, 383 μg kg−1, 345 μg kg−1 in E-FRFR of Yalin (+), respectively. 相似文献
19.
An antagonist yeast strain, WY-1, was identified using 18S and internal transcribed spacer (ITS) 1-5.8S-ITS2 rDNA region sequences. The 18S and ITS1-5.8S-ITS2 rDNA sequences of this yeast strain were amplified and sequenced using the universal primer pairs NS1/NS8 and ITS4/ITS5. The ITS1-5.8S-ITS2 rDNA sequence and 18S neighbor-joining tree showed that WY-1 was a strain of Cryptococcus albidus. The biocontrol activity of C. albidus WY-1 on postharvest decay of radishes caused by Alternaria spp. and Fusarium spp. was investigated. In vitro, at 108 CFU ml−1 C. albidus WY-1 inhibited the mycelial weight increases of Alternaria spp. and Fusarium spp. by 45.3% and 59.6%, respectively. In vivo, infection incidence and lesion development of radish decay were suppressed by the application of C. albidus WY-1 at 108 CFU ml−1. After 6 days of incubation at 20 °C or 24 days at 4 °C, disease incidences were 2.8% and 1.4%, respectively; however, the disease incidences of control fruit were 98.6% and 87.5% under these incubation conditions, respectively. Application of C. albidus WY-1 and the chemical fungicide thiabendazole were statistically just as effective. Finally, C. albidus cell counts around inoculation sites remained high at 4 °C even 32 days after inoculation (6.7 × 105 CFU per cm2). 相似文献
20.
《Industrial Crops and Products》2005,21(1):81-87
The leaf pulp of Aloe vera, designated as the gel, and the bitter, yellow liquid fraction have been tested against pathogens (bacteria and fungi) affecting human and plants. However, their activity for fungal control in commercial industrial crops has not been determined. The objectives of this study were to evaluate the inhibitory effect of Aloe pulp and liquid fraction on the mycelial growth of three phytopathogenic fungi and to determine the extract concentrations that can inhibit mycelial development. A. vera leaves were cut from plants grown under greenhouse conditions at the University Antonio Narro, disinfected with sodium hypochlorite, and separated in two groups. In the first group, the pulp was manually scraped out; in the second, a laboratory roll processor was used for the pulp and liquid fraction separation. Both types of extracts were pasteurized. Antifungal activity of pulp and liquid fraction was evaluated on the mycellium development of Rhizoctonia solani, Fusarium oxysporum, and Colletotrichum coccodes that were isolated from a potato crop by the hyphae point and monosporic techniques. The concentrations of the plant extract ranged from 0 to 105 μl l−1. Fungal plugs 0.4 mm in diameter were placed in Petri dishes with a potato–dextrose–agar (PDA) culture media, and treated with various concentrations of pulp or liquid fraction. The cultures were incubated at 24±2 °C and the radial growth of mycelia measured daily for 7 days. The antifungal effect was measured under a totally random design with four replications. The results showed an inhibitory effect of the pulp of A. Vera on F. oxysporum at 104 μl l−1 and over a long period. For the two types of Aloe fractions the activities were similar. Besides the liquid fraction reduced the rate of colony growth at a concentration of 105 μl 1−1 in R. solani, F. oxysporum, and C. coccodes. This is the first report of any Aloe liquid fraction activity against plant pathogenic fungi. 相似文献