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1.
植物生长调节剂与普克唑对芒果采后病害的影响   总被引：1，自引：0，他引：1  
植物生长调节剂2,4-D、GA_3或NAA与普克唑(Prochloraz)处理“紫花”芒果,使普克唑对采后炭疽病和蒂腐病的控制、减少腐烂损失、延长贮藏寿命、提高销售可按受率等效果显著增加。对急需黄熟出售和无需延期贮藏的芒果处理以乙烯利、普克唑混合溶液,催熟3～5天黄熟可食,无病害症状,销售可接受率100％。按销售期长短选用植物生长调节剂以配合普克唑的采后处理,是一个减少芒果采后病害腐烂、延长贮藏寿命、提高贮藏品质的高效、方便而经济的措施。  相似文献   

2.
A Gram-positive and catalase positive Staphylococcus strain was found to be associated with spongy tissue defect of Alphonso mango. The organism was identified to species level by physiological, morphological and biochemical characterization and fatty acid profile. The strain was identified as Staphylococcus xylosus (IMTECH, India, Accession No. MTCC 7441). The optimal growth of the organism was observed in the pH range of 5.0–9.0 and temperature range of 10–45°C. It was mannitol and arabinose-positive and able to produce acid from various sugars. The organism was able to grow in a medium containing 2–10% NaCl. It was further identified to species level by genomic sequencing of 1,387 base pairs of DNA (Gene Bank accession No. EU019195). Based on nucleotide homology and phylogenetic analysis, the microbe was found to be S. xylosus. The survey of Alphonso mango trees with a known history of producing spongy fruits showed that some of the twigs, leaves and flowers were coated with a honeydew-like sticky substance and mango hopper insects were observed over the inflorescence. The source of contamination of spongy fruits by S. xylosus was in the sticky mass. Gram staining, the catalase test and morphological features of the culture isolated from the sticky mass exhibited characteristics identical to the Staphylococcus strain isolated from the spongy pulp. Pathogenicity tests on different varieties of mangoes, apples and guavas indicated that the disease was experimentally transmitted from infected to healthy fruits. This observation suggested that this organism develops spongy symptoms in the fruits post-harvest and lacks specificity. In inoculated fruits, catalase and peroxidase enzymes were expressed as in naturally infected fruits. This report shows that the infection by S. xylosus could be a major initiating factor for spongy tissue development in Alphonso mangoes.  相似文献   

3.
为掌握我国杧果中甲氧基丙烯酸酯和三唑类杀菌剂残留的风险水平，建立了高效液相色谱-串联质谱技术同时测定吡唑醚菌酯、苯醚甲环唑等13种杀菌剂的分析方法，并运用点评估法对儿童和成人的长期及短期膳食暴露风险进行评估。结果表明:13种杀菌剂在1~100 μg/L范围内线性关系良好，决定系数R2≥0.9994，定量限 (LOQ) 为5 μg/kg；在5种不同添加水平下，平均回收率为76%~122%，相对标准偏差(RSD)为0.7%~14%。残留检测结果显示:我国杧果主产区和消费城市1056份全果样品中检出率较高的杀菌剂有吡唑醚菌酯 (22.6%)、嘧菌酯 (18.5%) 和苯醚甲环唑 (15.5%)。运用杀菌剂50th和97.5th百分位点的残留值分别计算对长期摄入风险的贡献率和短期膳食摄入风险。结果表明:杧果中吡唑醚菌酯等13种杀菌剂对成人和儿童的长期摄入风险的贡献率分别为0.01%~0.5%和0.01%~0.3%，9种有急性参考剂量的杀菌剂残留在成人和儿童中短期暴露风险商分别为0.01%~7.2%和0.02%~28.9%，通过杧果摄入13种杀菌剂对人体产生的长期和短期膳食摄入风险较小。根据上述杀菌剂在我国杧果上的登记情况、GB 2763—2021《食品安全国家标准 食品中农药最大残留限量》以及膳食评估结果，建议加强对醚菌酯、丙环唑、腈菌唑、氟硅唑、腈苯唑、氟环唑和三唑醇7种杧果上未登记农药的监管，修订吡唑醚菌酯及制定肟菌酯等杀菌剂在杧果中最大残留限量(MRL)。  相似文献   

4.
Volatile organic compounds (VOCs) collected from potato tubers inoculated with Phytophthora infestans (late blight), Fusarium coeruleum (dry rot) or sterilized distilled water (as a control) were analysed using gas chromatography–mass spectrometry (GC–MS) and gas chromatography–flame ionization detection (GC–FID). A total of 52 volatiles were identified by GC–MS in the headspaces above P. infestans- and F. coeruleum- inoculated tubers after incubation for 42 days in the dark at 10°C. Of these VOCs, the six most abundant were common to both pathogens. These were benzothiazole (highest abundance), 2-ethyl-1-hexanol (second highest abundance), and at approximately equal third abundance, hexanal, 2-methylpropanoic acid-2,2-dimethyl-1-(2-hydroxy-1-methylethyl)-propyl ester, 2-methylpropanoic acid-3-hydroxy-2,4,4-trimethyl-pentyl ester and phenol. In addition, styrene also occurred at approximately equal third abundance in the headspace of F. coeruleum- inoculated tubers, but at lower abundance in the headspace of P. infestans- inoculated tubers. Some VOCs were specific to each pathogen. Butanal, 3-methylbutanal, undecane and verbenone were found at low levels only in the headspace of tubers inoculated with P. infestans , while 2-pentylfuran and copaene were found only in the headspace of tubers inoculated with F. coeruleum . Additionally GC–FID analysis identified ethanol and 2-propanol in the liquid exudate from both P. infestans - and F. coeruleum -inoculated tubers after incubation for 35 days, and in the headspace after incubation for 42 days. These data provide key information for developing a sensor-based early warning system for the detection of postharvest diseases in stored potato tubers.  相似文献   

5.
Pre- and post-harvest control of mango anthracnose in the Philippines   总被引：4，自引：1，他引：4  
Two field trials were conducted in the Philippines in successive years to compare the effectiveness of different pre- and post-harvest treatments on the development of anthracnose on mango fruits caused by Colletoirichum gloeosporioides. In one experiment, the pre-harvest application of benomyl (250 mg/l a.i.) significantly reduced the number of conidia sampled in tree canopies compared with control trees (no fungicide) and was associated with a significant reduction in the post-harvest development of anthracnose on fruits. A hot-benomyl dip (850 mg/l a.i. at 52 55 C for 10 min) completely eradicated anthracnose on fruit treated on the day of harvest. In a second experiment, pre-harvest applications of prochloraz (500 mg/l a.i.) either within a pre-planned spray schedule or applied strategically (when 18 h or more continual leaf wetness was recorded by a sensor placed within a tree canopy) gave the best control of anthracnose on fruits. A hot-benomyl dip was again the most effective post-harvest treatment for fruit treated on the day of harvest and on the day after. There was no significant difference, however, between hot-benomyl dips or prochloraz dips (500 mg/l a.i. for 10 min) at ambient temperatures when fruit were treated on the third day after harvest. The implications of these results for the production and treatment of Carabao mangoes in the Philippines are discussed.  相似文献   

6.
The volatile metabolites of the headspace gas of onion bulbs inoculated with three different pathogens, Erwinia carotovora ssp. carotovora, Fusarium oxysporum and Botrytis allii, were profiled using gas chromatography/mass spectrometry. Differences in the number and amount of volatile metabolites were observed. Two hundred and fifty three volatile metabolites were detected in bulbs inoculated with three pathogens or sterile distilled water. On day three, 202 volatile metabolites were observed, compared to 166 on day six. Of the 253 compounds, however, only 59 occurred relatively consistently over replications, of which 25 compounds were specific to one or more pathogens, including 10 that were unique to a pathogen. Metabolites such as 1-Oxa-4,6-diazacyclooctane-5-thione and 4-mercapto-3-(methylthio)--(thio-lactone)-crotonic acid were exclusive to onions inoculated with F. oxysporum. Acetone, acetic acid-hydrazide, propylcarbamate, 1-bromo-1-propene, thiirane, 1-(methylthio)-E-1-propene and 1-ethenyl-4-ethyl-benzene were specific to B. allii. 3-bromo-furan was specific to E. carotovora ssp. carotovora. Sterile water-inoculated bulbs produced 3,3-dioxy-1,2-propanediol-tetranitrate. Highest amount of sulfurs was found in pathogen-inoculated, while highest amounts of terpenes, aromatics and aliphatics were found in sterile distilled water-inoculated bulbs. The possible use of these differences in the volatile metabolites for detecting and discriminating diseases of onion in storage is discussed.  相似文献   

7.
芒果Mangifera indica L.是我国著名的热带水果, 近年来细菌性病害发生严重。2020年－2021年对广西百色地区的芒果病害进行调查发现, 一种细菌性坏死病与细菌性黑斑病混合发生, 一般发病率30%~60%, 严重可达90%以上。本研究先后从该地区不同芒果坏死病组织中分离得到泛菌属的21株细菌。根据形态、生理生化特性、16S rDNA、fusA、gyrB、leuS、pyrG、rlpB和rpoB的多基因系统发育分析、致病性测定等方法将21个菌株分别鉴定为Pantoea vagans、P. anthophila、P. dispersa 和P. cypripedii。其中P. anthophila、P. dispersa 和P. cypripedii引起芒果细菌性坏死病是中国首次报道。  相似文献   

8.
The effectiveness of curing oranges and lemons at 33 degrees C for 65h followed by storage under ambient and cold-storage conditions was investigated. This treatment effectively reduced the incidence of Penicillium digitatum (Pers) Sacc and P italicum Wehmer decay on inoculated and naturally infected oranges and lemons stored at 20 degrees C for 7 days. However, it failed to control green and blue mould infections on fruits placed in long-term cold storage, except green mould on oranges, which was effectively controlled. Dipping fruits in a sodium carbonate solution (20 g litre(-1)) for 2.5 min following a curing treatment at 33 degrees C for 65 h satisfactorily reduced green and blue mould incidence during subsequent long-term storage at 4 degrees C on oranges and at 10 degrees C on lemons. The efficacy was greater on injured fruits inoculated after the combination of treatments was applied, achieving a 60-80% reduction in decay in comparison with the curing treatment alone in all cases. A significant reduction of blue mould was also observed on fruits inoculated both before the treatments and on those re-inoculated after the treatments, demonstrating both protectant and eradicant activity. Thus, combining curing at 33 degrees C for 65 h with sodium carbonate treatment effectively controlled these post-harvest diseases on artificially inoculated citrus fruits and protected against re-infection. With naturally inoculated lemons, curing followed by sodium carbonate significantly reduced both green and blue mould incidence, but was not superior to curing alone. With naturally infected oranges, curing significantly reduced blue mould, but decay was not reduced further when followed by sodium carbonate treatment.  相似文献   

9.
<正>灰葡萄孢菌(Botrytis cinerea)引起的灰霉病可导致植物幼苗猝倒或花朵和果实腐烂,多在冬春季节发生,是保护地蔬菜、水果和花卉生产或储藏过程中一类重要的病原菌。灰霉菌的初侵染主要由菌核或病残体在适宜温湿度时萌发产生的菌丝或孢子侵染植物,关于灰葡萄孢菌的菌丝、分生孢  相似文献   

10.
Research work was carried out to identify and ascertain the species status of the mango biotype of Colletotrichum gloeosporioides infecting mangoes in Ghana. Forty five isolates of Colletotrichum species were collected from 12 districts in Ghana while five each were obtained from mango fruits from Florida, Mexico and Puerto Rico. The entire internal transcribed spacer region, partial beta-tubulin gene and partial glyceraldehyde-3-phosphate dehydrogenase gene of isolates were sequenced and used in phylogenetic studies. The results of the sequence analysis of the first ribosomal transcribed spacer (ITS 1) region showed that 35 % of the isolates from Ghana and all the five isolates from Mexico were the mango biotype of C. gloeosporioides, while the others were not. Phylogenetic studies showed that the mango biotype of the pathogen was Colletotrichum asianum but not C. gloeosporioides as previously thought. However, the other isolates that were not the mango biotype were identified as Colletotrichum siamense and Colletotrichum species which had probably cross-infected mango from other fruit crops in the field.  相似文献   

11.
Weaver ants, Oecophylla smaragdina (Fabricius), can be used to manage insect pests in mango orchards in the Northern Territory of Australia, but previously unidentified black marks on fruit can reduce fruit marketability. To determine the cause of the marks, and to reduce the number of fruits by such marks, field experiments were conducted in three mango orchards in the Darwin area of Australia in 2001 and 2002. The results from netting bag-rearing showed that the black marks on fruit were due to the deposition of weaver ant formic acid, and fighting between weaver ant colonies was the major cause of the deposition. In treatments without isolation of weaver ant colonies, an average of 4.8% of fruits with the ant marks were downgraded, and this damage level was reduced to 2.1% in treatments with isolation of weaver ant colonies. Because of weaver ant foraging behaviour, this small proportion of downgraded fruits was unavoidable, but the benefits of the ants as biocontrol agents against a range of pests outweighs the cost of the damage the ants cause.  相似文献   

12.
Bacterial apical necrosis is a critical disease in the main production area of mango in Europe. It is caused by Pseudomonas syringae pv. syringae, and produces necrotic lesions on mango buds and leaves, causing severe yield losses due to a decrease of flowering and fruit set. A field study to evaluate control treatments against bacterial apical necrosis was carried out during three seasons on mango trees cv. Tommy Atkins in Huelva (Spain). Experimental treatments included Bordeaux mixture, fosetyl-Al, acibenzolar-s-methyl, gibberelic acid, silicon gel, a mixture between acibenzolar-S-methyl and Bordeaux mixture, and combined applications of fosetyl-Al with Bordeaux mixture or silicon gel. The treatments which caused a consistent reduction in bacterial apical necrosis symptoms at similar levels to the conventional treatment with Bordeaux mixture, were the plant resistance activator acibenzolar-S-methyl and the phosphonate derivative fosetyl-Al applied singly or in combination with other compounds, which could be alternative treatments. These treatments showed a significant decrease in the necrotic buds and/or leaves numbers; however, minor differences in P. syringae-like population levels were observed. The analysis of the inhibitory and bactericidal concentrations of cupric compounds against P. syringae strains isolated from mango tissues suggests that the commercial copper-based treatments with Bordeaux mixture used in the management of mango crops do not work in a bactericidal mode of action.  相似文献   

13.
Benzothiadiazole (BTH), as Bion WG50, and acetylsalicylic acid (ASA) treatments of potato foliage of field- and glasshouse-grown potato plants were compared for control of two foliar diseases, early blight ( Alternaria solani ) and powdery mildew ( Erysiphe cichoracearum ). The effect of these treatments on harvested tubers wound-inoculated with the dry rot fungus ( Fusarium semitectum ) was also evaluated. BTH (50 mg a.i. L−1) gave almost complete control of both foliar pathogens on inoculated glasshouse-grown plants and reduced the severity of leaf spotting diseases (mainly early blight) in the field. BTH (100 mg a.i. L−1) and ASA (400 mg a.i. L−1) reduced the severity of dry rot in field-grown tubers in some post-harvest wound-inoculated treatments but not others and a similar reduction occurred with tubers inoculated post-harvest from BTH-treated plants grown under glasshouse conditions. BTH treatment increased β-1,3-glucanase activity in leaves > stem > tubers > stolons but not in roots. Increased enzyme activity was recorded for up to 45 days post-treatment.  相似文献   

14.
Lasiodiplodia theobromae (Pat.) Griff. & Maubl, Neofusicoccum parvum Pennycook & Samuels, N. mangiferae Syd. & P. Syd., and Fusicoccum aesculi Corda, all anamorphs of Botryosphaeriaceae species, are the causal agents of mango stem-end rot and fruit rot in Taiwan. Identification of these fungal species based on morphology has not been easy due to their extensive plasticity for some of the morphological characters. To aid reliable identification of Botryosphaeriaceae species associated with mango fruits, four pairs of species-specific primers were designed according to sequences of the ribosomal internal transcribed spacers (ITS), and a rapid method was established based on nested multiplex polymerase chain reaction (PCR) in this study. To perform the analysis, PCR was first run with ITS1 and ITS4 as the primers, followed by a second PCR with the addition of all four sets of species-specific primers. With this method, a low limit of 100?fg-1?pg of purified fungal DNA was detectable. It could also successfully detect L. theobromae, N. parvum, N. mangiferae and F. aesculi in total DNA extracted from inoculated mango fruits. This assay provides a rapid and sensitive method for the identification of Botryosphaeriaceae species and diagnosis of mango fruit rot and stem-end rot as well.  相似文献   

15.
 采后腐烂给柑橘产业带来巨大的经济损失。本研究对2018年从陕西城固采集的温州蜜柑发病果实样品进行了病原菌的分离、柯赫氏法则验证和病原菌鉴定,证实获得的菌株CBS1可以通过伤口侵染温州蜜柑、椪柑、沃柑和伦晚脐橙果实,引起果实腐烂。基于形态学鉴定和ITS序列分析,将菌株CBS1鉴定为Rhizopus stolonifer,并对其生物学特性进行了初步研究。这是我国R. stolonifer侵染柑橘果实的首次报道。  相似文献   

16.
Mango wilt, caused by Ceratocystis fimbriata, is one of the most important diseases affecting mango yields in Brazil. Information regarding the infection process of C. fimbriata in the stem tissues of mango from different cultivars and the basis of host resistance to the pathogen is rare in the literature. Thus, the objective of the study was to investigate how infection by two isolates of C. fimbriata can be affected by mango cultivar‐specific mechanisms of resistance. Disease progress on the inoculated stem tissues of the mango cultivars was evaluated and stem sections were obtained from the site of inoculation and prepared for histopathological observations using light microscopy. The factors mango cultivars and C. fimbriata isolates and their interaction were significant for all measures of disease development. Plants from the cultivars Espada, Haden and Palmer inoculated with isolates of C. fimbriata were more susceptible, whereas plants from the cultivars Tommy and Ubá were moderately resistant and resistant, respectively. Histopathologically, fungal isolates apparently massively colonized the stem tissues of plants from the susceptible cultivars Espada, Haden and Palmer, starting from the collenchyma and moving in the direction of the cortical parenchyma, xylem vessels and pith parenchyma. By contrast, on stem tissues of plants from the resistant cultivars Tommy Atkins and Ubá, most of the cells reacted to C. fimbriata infection by accumulating amorphous material. The results from the present study strongly indicated the importance of phenolic compounds for mango cultivar resistance against infection by Brazilian C. fimbriata isolates.  相似文献   

17.
Fifty-nine Ralstonia solanacearum isolates from diverse crops and regions were collected and characterized to determine the distribution and diversity of this soilborne pathogen in Guatemala. Three distinct types were present: a phylotype I, sequevar 14 strain, probably originating from Asia, infecting tomatoes and aubergines at moderate elevations; a phylotype II, sequevar 6 strain of American origin causing Moko disease in lowland banana plantations; and a phylotype II, sequevar 1 (race 3 biovar 2) strain causing brown rot on potatoes, Southern wilt of Pelargonium spp. and bacterial wilt of greenhouse tomatoes at high elevations. These data on strain diversity will inform effective regional efforts to breed for wilt resistance. A sensitive enrichment method did not detect the pathogen in fruits from naturally infected commercial tomato plants in Guatemalan fields and greenhouses, although it was detected in 6% of fruits from a wilt-resistant hybrid. Low numbers of R. solanacearum cells were also infrequently detected in fruits from plants artificially inoculated in the growth chamber with either race 3 biovar 2 or a phylotype II tomato strain.  相似文献   

18.
Mango malformation, caused by the fungus Fusarium mangiferae , is one of the major diseases of this crop occurring worldwide. This study was conducted to investigate aspects of the epidemiology, survival and spread of the pathogen in general and specifically in seedlings, the majority of which are cultivated in infected orchards in Egypt. Survival of conidia of a representative isolate (506/2) declined very rapidly in soil under summer conditions (1·6 weeks for 50% population decline), but significantly less in controlled and winter conditions (17·9 and 15·0 weeks, respectively, for 50% population decline). Likewise, inoculum survival in naturally infected panicles on the soil surface declined faster than in those buried at 30-cm depths. Natural infections were evaluated on fruits and seeds in a heavily infected and a healthy orchard. In infected trees, the skins of all sampled fruits within a 2-m radius of infected panicles were infected, but the pathogen was not detected in the seeds, seed coats or flesh. The pathogen was not detected in any parts of fruits from a healthy orchard. Vegetatively malformed mango seedlings, growing under infected trees bearing infected panicles, were sampled in two locations in Egypt to determine whether infection in seedlings was systemic (evenly distributed within plant tissue) or whether the pathogen originated from malformed panicles. According to PCR-specific primer amplification, the pathogen was detected in 97% of seedling apical meristems, declining gradually to 5% colonization in roots. It was concluded that inoculum of the pathogen originates from infected panicles and affects seedlings from the meristem, with infections descending to lower stem sections and roots. Minor infections of roots may occur from inoculum originating from infected panicles, but the pathogen is not seedborne.  相似文献   

19.
Infection estimates determined by a predictive model developed by Dodd et al . (1991b) were used to time fungicide sprays to control anthracnose disease of mango in the Philippines. For an amount of disease on fruits after harvest which was acceptable to growers, this approach resulted in the application of five fewer sprays compared with a standard spray programme used by the growers in a field trial conducted in 1991–1992. The model predicted only two high anthracnose-risk periods (>40% of conidia forming appressoria) throughout the duration of the growing period. Rainfall intensity and its time of occurrence during fruit development was found to greatly influence the amount of anthracnose and stem-end rot disease on fruits after harvest. Three relatively strong precipitations (>20 mm) within a month before harvest resulted in relatively high anthracnose infection of fruits after harvest. At a second field trial, rainfall periods during fruit development did not exceed 4 mm and resulted in virtually disease-free fruits after harvest, including those not treated with fungicide. Again the use of the predictive model resulted in the elimination of five fungicide treatments compared with the standard programme. The amount of rainfall and the time of its occurrence should be considered when planning a disease management scheme for the control of anthracnose on mango fruit.  相似文献   

20.
黄瓜绿斑驳花叶病毒对西瓜产量、品质及种子带毒的影响   总被引：1，自引：0，他引：1  
研究了西瓜不同时期接种黄瓜绿斑驳花叶病毒(Cucumber green mottle mosaic virus,CGMMV)后对其生长、产量、品质和种子带毒的影响。西瓜植株接种CGMMV越早其生长受到抑制越明显,砧木期、嫁接后定植前、定植期、压蔓期、授粉期各处理的株高、叶片数、叶片长与对照相比差异极显著(p0.01),而结瓜以后接种CGMMV对西瓜生长状况无显著影响。压蔓期前3个生育期接种该病毒,西瓜产量损失分别为56.49%、55.48%和51.14%。而压蔓期以后接种该病毒,西瓜产量损失与对照相比仍分别降低17%、13.1%和14.35%。关于倒瓤情况,压蔓期前接种该病毒可导致西瓜果实100%倒瓤,压蔓期、授粉期接种处理西瓜倒瓤率分别为48%和34%,即使结瓜后再接种病毒西瓜倒瓤率仍高达18%。血清学检测表明,压蔓期前接种的西瓜其果肉和种子均携带CGM-MV,带毒率达100%;结瓜后再接种CGMMV西瓜种胚和果肉的带毒率仍然高达64%。检测种胚和果肉病毒含量表明,接种时期越早病毒含量越高,但结瓜后接种仍有较高的病毒含量,种胚和果肉的病毒含量分别达5.98 mg/mL和5.64 mg/mL。  相似文献   

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