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1.
Various preparations of spores and mycelium of the antagonist Epicoccum nigrum , alone or in combination with Captan, were applied in four different field trials to peach trees inoculated with Monilinia laxa , the cause of twig blight. Biocontrol obtained after application of E. nigrum was variable each year, depending on the releative disease severity in the first 2–3 weeks after infection and the climatic conditions. In three out of four trials, treatments with E. nigrum were comparable with Captan in reducing disease severity and combinations of E. nigrum and Captan gave a level of disease suppression similar to that given by the antagonist or chemical alone. In the remaining trial, combinations of E. nigrum and Captan were necessary to obtain successful disease suppression. 相似文献
2.
Since the early nineties control of twig blight on sour cherries in Rheinhessen/Germany caused by Monilinia laxa has become more and more difficult. Severe twig blight incidence even occured during cold and dry periods despite several hours of wetness are necessary for flower infecions by M. laxa conidia. Also repeated fungicide applications during bloom did not provide reliable control of twig blight. Field and laboratory studies have been carried out from 2002–2005 to find the reasons for control failures and the infection process under cold and dry conditions. On the basis of field observations frost damage of flowers and inoculum transport from untreated old cherry trees could be excluded. Monitoring studies revealed that only M. laxa caused twig blight and not M. fructicola as assumed before. The reason for the severe twig blight damage is the fact that M. laxa causes 2 different forms of twig blight. Besides the well known and often described twig blight after flower infection during rainy periods a second form of twig blight exists also caused by M. laxa but starting from “latent” infections inside the twig. These “latent” or “early” twig blight symptoms already occur at full bloom even during dry weather periods. Fungicide applications at the flowering stage do not control this form of twig blight because M. laxa is already present inside the twig. A diagnostic system is described allowing a clear differentiation of the two forms of twig blight what will lead to a reduced number of fungicide applications. Only the “true” flower infections can be controlled by fungicide treatments. 相似文献
3.
During the period 1978–1992, phenylamide fungicides in co-formulation with the dithiocarbamate fungicide mancozeb were tested for the control of potato late-blight in 51 separate field experiments in England and Wales. Whilst there was a general trend over all the experiments which indicated that foliage blight was less severe where the phenylamide + dithiocarbamate mixture had been used, the benefit was more marked in some than in others. Despite the detection of phenylamide resistance, at some sites the mixture gave better control of foliage blight than the dithiocarbamate alone. At one site where continuous data were available, the additional benefit of the phenylamide compound for control of foliage infection was lost after 1986 coinciding with a rise in phenylamide resistance from 31.7% in 1986 to 81% in 1987. Where foliar blight epidemics occurred, yield responses to fungicide programmes compared with unsprayed controls ranged from 0 to +118.5% with a mean response of +30.2%. This is equivalent to 30.8 and 12.92 t/ha respectively. Standardized yield differences were calculated to allow inter-trial and inter-year comparisons and showed no benefit from the phenylamide fungicide applied at 14-day intervals in 33 out of 38 experiments where foliar blight epidemics occurred. At one site, Cusum analysis of standardized yield differences following treatment with the phenylamide + dithiocarbamate mixture and the dithiocarbamate alone showed a mean benefit from the phenylamide mixture of 2.23 t/ha during the period 1978 to 1986. From 1987 to 1992, the yield benefit dropped to a mean level of 0.68 t/ha a decrease of 69.5%. In experiments where blight was not recorded, fungicide treatments had no deleterious effect on yields. Over all the trials, there was no effect of fungicide treatment on the incidence of tuber blight at harvest. 相似文献
4.
Isolates of Erwinia herbicola , obtained from flowers and leaves of hawthorn ( Crataegus monogyna) , were screened as potential control agents of fire blight disease (caused by Erwinia amylovora) using an immature pear fruit assay. Selected isolates were subsequently tested for disease control by infection of hawthorn blossom in the laboratory, and by shoot infection of hawthorn plants grown under controlled (glasshouse) and fluctuating (polythene tunnel) environmental conditions.
Although the immature pear fruit assay provided a general screen for the selection of antagonists for the control of both blossom and shoot blight, it had two major limitations when quantitatively applied. Firstly there were inconsistencies in the relative effects of different isolates on the pear-slice surface, with some isolates being more suppressive than the standard antagonist Eh252 in the first screening and less in the second. Secondly the assay was not able to predict accurately the level of control in the intact plant-as no correlation occurred between the level of control in the pear fruit assay and the percentage control of either blossom blight or shoot blight.
Two isolates of E. herbicola , WL9 and WL40, reduced both blossom- and shoot-blight. WL9 provided over 80% control of blossom blight, equivalent to that provided by chemical agents, and also gave total control of shoot blight when applied at a WL9: pathogen ratio of 10:1. 相似文献
Although the immature pear fruit assay provided a general screen for the selection of antagonists for the control of both blossom and shoot blight, it had two major limitations when quantitatively applied. Firstly there were inconsistencies in the relative effects of different isolates on the pear-slice surface, with some isolates being more suppressive than the standard antagonist Eh252 in the first screening and less in the second. Secondly the assay was not able to predict accurately the level of control in the intact plant-as no correlation occurred between the level of control in the pear fruit assay and the percentage control of either blossom blight or shoot blight.
Two isolates of E. herbicola , WL9 and WL40, reduced both blossom- and shoot-blight. WL9 provided over 80% control of blossom blight, equivalent to that provided by chemical agents, and also gave total control of shoot blight when applied at a WL9: pathogen ratio of 10:1. 相似文献
5.
Brigitte Dorn Tomke Musa Heinz Krebs Padruot Men Fried Hans Rudolf Forrer 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(2):217-240
In order to replace copper fungicides in organic potato production, 53 copper-free preparations (CFPs) based on natural compounds,
including plant extracts and microorganisms, and five copper preparations were evaluated for their potential to control Phytophthora infestans, the pathogen that causes late blight of potatoes. In in vitro assays, 30% of the CFPs inhibited indirect germination of
sporangia, 26% mycelial growth and in growth chamber experiments, 21% efficiently reduced foliar blight of tomato plants.
In micro-plot field trials with applications twice a week, the copper preparations were the most effective and reduced foliar
blight by 99%. Of the CFPs tested, Oekofluid P, Mycosin and other sulphuric clays, and C-2000 reduced late blight the most,
from 63% to 37%. In small-plot trials in 2001, 2002 and 2004, 27 CFPs with different formulations and four copper preparations
were examined. In 2004, copper preparations at full and reduced rates and sulphuric clays were applied either weekly or according
to the decision support system Bio-PhytoPRE. With Bio-PhytoPRE, copper preparations reduced foliar blight of potatoes by 23–77%
and increased tuber yield by 2–28%, depending on the copper rate applied and year. With CFPs, maximal efficacy was 17% and
no effect on tuber yield was observed. In vitro and in vivo trials showed that the rainfastness and the persistence of CFPs
was low compared with copper preparations. This indicates that the failure of CFPs under field conditions is probably due
to a lack of stability under prevailing environmental conditions and not to a lack of efficacy. Until stable formulations
for CFPs are developed, an optimised and restricted use of copper fungicides using a decision support system could help to
control late blight in organic potato production and to reduce copper input into the environment. 相似文献
6.
A mixture (‘Fubol’) of metalaxyl with mancozeb, performed better than mixtures of propamocarb (as the hydrochloride) or the experimental fungicide cymoxanil with mancozeb, when applied as sprays to control potato blight in a small-scale field trial conducted in 1978. Another experimental fungicide, 2-chloro-N-(2-oxotetrahydrofuran-3-yl)acet-2″,6′-xylidide (RE 20615), applied at a greater rate but without mancozeb, was as effective as ‘Fubol’. The mixture of mancozeb and propamocarb or cymoxanil performed no better than mancozeb alone. In 1979, when blight incidence was greater, use of RE 20615/dithiocarbamate mixtures allowed the extension of spray intervals to 21 days, compared with a 14-day schedule for the dithiocarbamate alone. RE 20615, applied in 1979 to the soil within the furrows at planting time as a controlled-release granular formulation, gave adequate control of late blight up to early September, after which disease development accelerated. Yield was not significantly different from that obtained with a standard dithiocarbamate treatment. 相似文献
7.
The control of the rust fungus, Phragmidium mucronatum by seven fungicides (benodanil, fenpropimorph, oxycarboxin, thiram, triadimefon, triazbutyl and triforine), was examined both in vivo and in vitro. Oxycarboxin applied at monthly intervals to field-grown Rosa laxa gave excellent control. Similar results were obtained on detached leaflets using the fungicide as a protectant or eradicant. A benodanil-resistant isolate was identified in axenic culture. 相似文献
8.
A twig and stem blight of cotton ( Gossypium hirsutum ) was observed in Tamil Nadu, India in 1977. The causal organism was isolated in pure culture and identified as Botryodiplodia theobromae , a first record of this species causing twig and stem blight on cotton. Typical fruit rot symptoms were produced on several inoculated fruits but not Citrus sp., Punica granatum or Achras sapota. 相似文献
9.
Erland Liljeroth Therése Bengtsson Lars Wiik Erik Andreasson 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(2):171-183
We have investigated to what degree induced resistance with β-aminobutyric acid (BABA) can protect potato from late blight
infection under Swedish field conditions and if synergistic interactions occur if BABA is applied in combination with a commonly
used fungicide, Shirlan. In greenhouse experiments we also investigated the durability of BABA induced resistance, the dose-response
relationships in susceptible (Bintje) and partially resistant (Ovatio, Suberb) cultivars and effects of combined applications
of BABA and fungicides. We found a clear effect of BABA on P. infestans infection of greenhouse grown potato plants. The lesion sizes were reduced by on average 40–50% compared to untreated control.
However, this effect lasted for only 4–5 days after BABA treatment and then the efficacy was lower. When BABA was given in
combination with the fungicides it appeared to have an additive effect both in greenhouse and field experiments. Higher concentrations
of BABA gave a stronger protective effect. The partially resistant cultivars Ovatio and Superb reacted to lower concentrations
of BABA where no effect was found in susceptible Bintje. According to our field data, 20–25% reduction of the fungicide dose
in combination with BABA gave on average the same result on late blight development as full dose Shirlan alone; while reduced
dose of Shirlan alone sometimes resulted in less effective protection. Our results indicate that induced resistance could
be used in practice in combinations with fungicides in order to reduce the amount of toxic compounds under north European
conditions. 相似文献
10.
Phoebe is a traditional precious tree species in China, which has great economic and ecological value. A new disease twig blight was found in the Phoebe planting area of Zhejiang province. Symptoms usually appear on the base or fork of branches with black swollen epidermis and gradually get worse resulting branch wilting or whole plant death when longitudinal epidermis cracking. The diseased samples were collected in 2017-2018 and the fungal isolate was identified as Lasiodiplodia pseudotheobromae based on morphological characteristics of colony and spore and sequence analysis of ITS region and EF1-α gene. The pathogenicity tests on Phoebe showed that L. pseudotheobromae caused the typical symptoms of twig blight. Koch′s postulates were satisfied following reisolation and identification of the isolate from the infected tissues using the methods described above. This is the first report of Phoebe twig blight caused by L. pseudotheobromae in China. 相似文献
11.
12.
Hai-Ying Ren Gang Li Xing-Jiang Qi Li Fang Han-Rong Wang Ji-Guang Wei Shaobin Zhong 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(3):451-461
Bayberry (Myrica rubra) is a fruit tree native to the subtropical regions of China. It produces fruit with a unique taste and pharmacological characteristics, thus making it a widely cultivated tree commercially in many regions of China, including Zhejiang, Fujian, Guizhou, Sichuan and Yunnan Provinces. Recently, a twig blight disease occurred on the fruit tree and caused destructive damage of plantings in the Zhejiang Province. However, the etiology of the disease was unclear. This study was carried out to identify the causal agent(s) of the blight disease on bayberry. Fungal isolates were obtained from blighted twig samples collected from bayberry fields in Xianju, Rui’an, and Huangyan of Zhejiang Province. The majority (87.9 %) of the 257 fungal isolates were identified as Pestalotiopsis spp. based on their conidial morphology. DNA sequences of the internal transcribed spacer (ITS) region of the ribosomal RNA gene and the β-tubulin gene were obtained from six representative strains (XJ27, XJ42, RA2-1, YS26, YS44 and RA1-2) of the Pestalotiopsis spp. Phylogenetic analysis showed that three of the strains (XJ27, XJ42, and RA2-1) grouped with P. versicolor (Speg.) Steyaert while the other three strains (YS26, YS44 and RA1-2) grouped with P. microspora (Speg.) Batista & Peres. Pathogenicity tests in the greenhouse showed that all these six isolates of Pestalotiopsis spp. caused twig blight disease symptoms on bayberry plants, which were the same as observed in naturally infected plants in the field. Our results clearly indicated that P. versicolor and P. microspora were the major pathogens causing the twig blight disease on bayberry in southern China. 相似文献
13.
A. C. PAPPAS 《Plant pathology》1985,34(2):293-296
In winter/spring 1984 resistance to metalaxyl developed in Phytophthora infestans within tomato greenhouses in Preveza, Greece. The appearance of resistant isolates followed continuous applications of metalaxyl and prevalence of weather conditions favourable for late blight. The majority of resistant isolates grew on tomato leaf discs floated on solutions containing 100 μg/ml metalaxyl whereas sensitive isolates were inhibited at concentrations of 0.1 μg/ml.
In trials within polyethylene tunnels metalaxyl had no effect on the development of the late blight induced by resistant strains but both a mixture of this fungicide with mancozeb and mancozeb alone, gave satisfactory control of the disease when applied in a 7-day schedule. 相似文献
In trials within polyethylene tunnels metalaxyl had no effect on the development of the late blight induced by resistant strains but both a mixture of this fungicide with mancozeb and mancozeb alone, gave satisfactory control of the disease when applied in a 7-day schedule. 相似文献
14.
In two trials established between 1983 and 1990, copper oxychloride and prochloraz-manganese applied at 5 and 50% leaf-fall were as effective as phenylmercury nitrate, formerly used (but now banned) for the control of leaf-scar infection by Nectria galligena. However, prochloraz-manganese has not been developed for use on fruit. Autumn application of carbendazim gave inadequate control and thiophanate-methyl, bitertanol and fenpropimorph were ineffective. Carbendazim applied as a spring-summer treatment reduced canker development to a similar level to a spring-summer dodine scab programme plus autumn copper oxychloride. Summer carbendazim + captafol was an outstandingly effective treatment, but since this trial the use of captafol as a fungicide in the UK has been prohibited. In the absence of an effective autumn treatment, penconazole alone or with captan, and myclobutanil preblossom with myclobutanil alone or with mancozeb post-blossom tended to be less effictive than the standard programme (dodine pre- and dithianon post-blossom). Carbendazim mixed with an effective scab fungicide such as dithianon therefore remains the recommended treatment in an orchard with a serious canker problem. In orchards where there is a limited risk of canker, a spring-summer scab fungicide programme should prevent N. galligena infection at this time of year, with copper oxychloride applied at leaf-fall, particularly after wet weather, to prevent leaf-scar infection. 相似文献
15.
The pathogenicity of Phytophthora cambivora to Mission almond seedlings was confirmed by twig inoculation in situ. An excised twig assay using four isolates of P. cambivora showed almond cvs Mission and Chellaston to be susceptible, whereas peach cv. Nemaguard, which is commonly used as a rootstock for almond, was resistant. P. cambivora isolates 179 and 108, the most and least aggressive, respectively, were selected for further studies. The excised twig assay was modified for screening micropropagated shoots in vitro for response to P. cambivora. Defoliated shoots were placed upright in agar medium colonized with the fungus, and development of necrosis was assessed over a period of 2-3 days. Shoots of Chellaston developed extensive necrosis and those of Nemaguard developed little necrosis, whereas shoots of hybrid selections from peach x almond crosses were generally intermediate in response. This method permits rapid and efficient screening of large amounts of material, and would be a useful adjunct to conventional almond breeding programmes. 相似文献
16.
蓝莓枝枯病拮抗细菌HMQAU140045的鉴定和抑真菌活性 总被引：1，自引：1，他引：0
以蓝莓毛色二胞枝枯病菌假可可毛色二胞Lasiodiplodia pseudotheobromae为靶标菌,通过稀释平板法从山东青岛的蓝莓种植园根际土壤中分离出20株细菌,采用对峙平板法和菌丝生长速率法筛选得到一株对靶标菌具有明显抑制效果的拮抗菌株HMQAU140045,采用凹玻片法和菌丝生长速率法测定该菌株发酵滤液对靶标菌孢子萌发和菌丝生长的影响。结果表明,稀释50倍的发酵滤液的抑制率可达100%。离体枝条试验结果表明,发酵液不同组分对蓝莓毛色二胞枝枯病的防治效果均可达90%以上。菌丝生长速率法测定结果表明,该菌株抑真菌谱广,对包括4种蓝莓枝枯病菌在内的15种植物病原真菌具有良好的拮抗作用。通过形态观察、生理生化特性以及gyrB的序列分析,确定该菌株为解淀粉芽孢杆菌Bacillus amyloliquefaciens。试验结果表明,解淀粉芽孢杆菌菌株HMQAU140045具有较好的抑真菌活性。 相似文献
17.
Excised twig assay and excised stem inoculation were used to evaluate nine fungicides (metalaxyl, fosetyl-Al, copper hydroxide,
copper sulfate, copper oxychloride, captan, quintozene, propamocarb and chlorothalonil) againstPhytophthora cactorum andP. citrophthora associated with crown rot in peach trees. Segments were soaked in fungicide solutions at different concentrations and then
inserted vertically intoP. cactorum orP. citrophthora cultures growing on cornmeal agar plus antibiotics, or inoculated by inserting a mycelium-bearing agar plug directly into
the cambium. Following incubation, the bark was scraped off and length of necrosis was measured. Metalaxyl was the only fungicide
that inhibited canker development on segments at the manufacturer-recommended concentration. Fosetyl-Al, captan, copper hydroxide
and copper sulfate inhibited canker development at 3, 4, 4 and 8 gl-1, respectively. The other fungicides did not affect canker length significantly compared with non-treated twigs, with the
exception of propamocarb, which reduced the development ofP. cactorum on excised stems. The tested methods enabled rapid and effective evaluation of a large number of chemicals to prevent crown
rot diseases caused byPhytophthora in the laboratory.
http://www.phytoparasitica.org posting Dec. 5, 2001. 相似文献
18.
BACKGROUND: Phytophthora blight induced by Phytophthora capsici is responsible for serious yield loss in vegetable production in the United States and other countries. This study was conducted to evaluate the efficacy of Brassica cover crops used as soil amendments for managing Phytophthora blight of squash. RESULTS: In greenhouse studies, disease incidence on squash plants was significantly reduced by soil amendment with mustard shoots or roots used at 1 and 2.5% (plant tissue/soil, w/w). The shoots of canola used at 1 or 2.5% also suppressed disease, while the roots of canola or other crops did not reduce disease significantly. In field studies, soil amendments with mustard and canola provided the greatest disease reduction and increased squash yield significantly compared with the non‐treated control. Mustard and canola did not appear to be susceptible to P. capsici. CONCLUSION: The results indicated that some Brassica crops, particularly mustard and canola, had the potential to significantly reduce Phytophthora blight on squash when used as soil amendments. As P. capsici has a remarkable ability to develop resistance to chemical fungicides, use of effective Brassica cover crops could be a biorational alternative to fungicides and a valuable component in developing integrated disease management programs. Copyright © 2011 Society of Chemical Industry 相似文献
19.
Barry K. Cooke Pamela J. Herrington Kenneth G. Jones Norman G. Morgan 《Pest management science》1975,6(6):571-579
In 3 year field experiments on pest and disease control by mobile overhead spraying of intensive Cox's Orange Pippin apple trees, overhead booms applying 1125 litres/ha and overhead mist-blowing equipment applying 562 litres/ha, each spraying two complete rows from one alley in half the normal time, were compared with conventional automatic mast spraying at 2250 litres/ha and with conventional mist-blowing at 562 litres/ha. The overhead boom application of demeton-S-methyl (0.0036% a.i.) with azinphos-methyl (0.0165% a.i.) or of fenitrothion (0.031% a.i.) at the green cluster stage gave control of the applegrass aphid, Rhopalosiphum insertum, virtually equal to that obtained by conventional application of the same insecticides. Similarly, the overhead mist applications of conventional quantities of insecticides gave equal control, but not when applying one-quarter of the normal amount of insecticides. The conventional methods generally gave better control of apple sucker, Psylla mali. In 1971, when the incidence of apple scab, Venturia inaequalis, was only moderate, the overhead boom method gave equal control to conventional spraying with both dodine/captan (0.03% a.i. and 0.094% a.i.) and benomyl (0.025% a.i.) programmes: in 1972 and 1973, when the scab incidence was heavier, the overhead boom spraying was again equal to the conventional method with the benomyl programme but was less effective with the dodine/captan programme. The overhead mist applications gave control only when the scab incidence was light. Repeated applications of dinocap emulsion (0.025% a.i.), included in the fungicide programme in 1971, gave as good control of the active stages of fruit tree red spider mite, Panonychus ulmi, when applied by the overhead methods as by conventional spraying, but application of the benomyl programme gave poor control. Mobile overhead spraying of small intensive apple trees is a promising method but needs further development before becoming fully acceptable. 相似文献
20.
Summary. Field experiments were conducted to find a herbicide for complete control of nutsedge ( Cyperus rotundus L.). We applied seventeen herbicides and some of their combinations as chemical fallow. EPTC and CP-31675 (6- tert -butyl-2-chloro-o-acetotoluidide) gave good but only temporary control of nutsedge. Dichlobenil at 2·5 or 5 lb/ac gave fair control for 1 year. Rates of 10 or 20 lb/ac of dichlobenil controlled nutsedge completely for 1 year but severely reduced the yield of oats planted 5 months after application. The highest rate completely killed tubers and prevented reinfestation for 1 year. Analyses indicated no residue of dichlobenil or of its metabolite, 2,6-dichlorobenzoic acid, in vegetative parts and seeds of oats planted 5 months after application of 2.5, 5 or 10 lb/ac of dichlobenil. At equivalent rates the herbicide TH-073-H (N-hydroxymethyl-2,6-dichlorothiolbenzamide) gave control of nutsedge similar to that with dichlobenil. The combinations of 8 lb/ac amitrole-T and 10 lb/ac dichlobenil or TH-073-H were just as effective in controlling nutsedge shoots and tubers as dichlobenil or TH-073-H applied alone. The mixture of dichlobenil plus CP-31675, each at 5 lb/ac, gave excellent control of nutsedge and tubers for 1 year. The herbicides terbacil ( 3-ter -Nbutyl-5-chloro-6-methyluracil) or Du Pont 733 ( 3-tert -butyl-5-bromo-6-methyluracil) at 10 lb/ac provided almost complete control of nutsedge. Application of terbacil to plants aged 4–6 weeks gave better results than application to mature nutsedge in the fall.
La lutte chimique contre le cypirus 相似文献
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