不同品系番茄对番茄刺皮瘿螨生长发育的影响

为了弄清楚不同番茄品种对番茄刺皮瘿螨Aculops lycopersici (Massee)的抗感性程度,通过田间调查、室内盆栽接螨和离体培养等方法,考察了12个番茄品种（系）（多茸毛类YZ618和YZ619;少茸毛类YZ419, YZ507和YZ504;野生品系YZ7和YZ5 叶黄类YZ401;常规品系YZ406,YZ412,YZ413和YZ515）上番茄刺皮瘿螨的种群发育情况。结果表明：番茄刺皮瘿螨在不同番茄品种（系）上的种群密度有明显差异,野生品系YZ7及多茸毛品系YZ618和YZ619上较低,少茸毛品系YZ504,YZ507和YZ419较高。不同番茄品种（系）可能是通过影响螨的存活率和产卵能力来影响在品种（系）上的种群发展。离体培养观察发现,番茄刺皮瘿螨的存活率在少茸毛品系YZ504和YZ507上最高,其次是品系YZ419,野生品系YZ7上最低。在YZ504上的产卵量最大,YZ419和YZ507次之,YZ7最小。根据实验种群参数判断,野生品系YZ7及多茸毛品系YZ618和YZ619感螨程度低,为抗性品系; 少茸毛品系YZ504,YZ419和YZ507感螨程度高,为感螨品系。     

Effect of flavonoids on the development of Fusarium oxysporum f. sp. lycopersici

Abstract

In the present study the effect of flavonoid compounds on the germination and fungal growth of the soil-borne tomato pathogen Fusarium oxysporum f. sp. lycopersici was studied. Out of 12 flavonoid compounds only myricetin and luteolin exhibited a low stimulating activity on microconidia germination of Fusarium oxysporum f. sp. lycopersici, whereas the other flavonoids tested were inactive when applied at five different concentrations. In our study the tested flavonoids affect fungal growth differently to microconidia germination. Individual flavonoid concentrations resulted in a small increase of fungal growth, but the lowest flavonoid concentrations showed an inhibiting effect on fungal growth for all flavonoids tested. There is evidence to suggest, that low flavonoid concentrations exhibit slight antimicrobial properties against Fusarium oxysporum f. sp. lycopersici.     

Improvements in the detection of pea seed-borne mosaic virus by ELISA

The detection by ELISA of pea seed-borne mosaic virus (PSbMV) in pea leaves and seeds was improved by the addition of cellulase or Triton X-100 to the extraction fluid, probably because the additives aided the release of virus particles from host materials. With leaf extracts the additives were most effective at 0.1%. In initial tests cellulase was used with macerozyme, but the latter enzyme was then shown to decrease the effectiveness of cellulase. Triton X-100 was as effective as cellulase and the absorbance values obtained in ELISA of infected leaf extracts, diluted to 1/10 in extraction fluid containing the additive, were about six times greater than those of infected extracts diluted in normal extraction fluid. Five named isolates of PSbMV, in addition to the homologous isolate, were readily detected in infected leaves extracted in fluid containing Triton X-100. In tests on seeds and seedlings of seven infected seed lots of pea cv. Waverex, using Triton X-100 in the extraction fluid, PSbMV was detected in five times as many seeds as seedlings, probably mainly because in many infected seeds the virus was in the testa and not in the embryo. About 9% of infected seedlings were without recognisable symptoms 4 wk after emergence.     

The Effect of Seed-Borne Pathogens on Emergence of Globe Amaranth, Calendula and Tagetes and the Methods of Control

Nimbya gomphrenae , Stemphylium vesicarium and Alternaria tagetica were isolated for the first time from seeds of diseased globe amaranth ( Gomphrena globosa ), pot marigold ( Calendula officinalis ) and marigold ( Tagetes erecta ), respectively, in Taiwan. The amount of seed-borne N. gomphrenae or Colletotrichum dematium was positively correlated (P=0.05) with the amount of the abnormal seedling and unemergent seed of globe amaranth. Similarly, the amount of seed-borne Alternaria alternata or S. vesicarium was negatively correlated (P=0.05) with the emergent rate of pot marigold. Treating the fungi-contaminated globe amaranth seeds with Bacillus megaterium [1.3 × 10⁹colony-forming units (CFU)/ml] or 1% NaOCl significantly (P=0.05) increased seed emergence over control whereas 10 p.p.m. pyrifenox could control N. gomphrenae on globe amaranth. Stemphylium -contaminated pot marigold seeds responded to 200 p.p.m. iprodione treatment by increasing significantly (P=0.05) in seed emergence over untreated control. For seed-borne A. tagetica , treating marigold seeds with Bacillus azotoformanis (1 × 10⁹CFU/ml) was found effective and mancozeb highly effective.     

Evaluation of the efficacy of immunomagnetic separation for the detection of Clavibacter michiganensis subsp. michiganensis in tomato seeds

Aims: To evaluate the effectiveness of the optimized immunomagnetic separation (IMS)‐plating protocol in relation to other culture, serological and molecular techniques currently used for Clavibacter michiganensis subsp. michiganensis in seed‐testing laboratories. Methods and results: Bacterial suspensions, tomato seed extracts spiked with the pathogen and naturally infected seeds were IMS‐plated for the detection of C. m. subsp. michiganensis. These results were compared with plating on general (YPGA) and semiselective (mSCM) media, double‐antibody sandwich enzyme‐linked immunosorbent assay (DAS‐ELISA), immunofluorescent assay (IF) or polymerase chain reaction (PCR). Different seed lots and pathogen strains were also tested. IMS‐plating allowed the detection of less than 10 CFU ml^?1 of pathogen in all assayed samples. The mSCM medium provided positive results for 10 CFU ml^?1 in naturally infected seeds, but up to 14 days was necessary for the typical colonies of the target to be come visible. By serological techniques, 10³ and up to 10⁴ CFU ml^?1 were detected by IF and ELISA, respectively. DNA extraction was required to obtain positive results by PCR in seed extracts containing 10³ CFU ml^?1 or more. Conclusions: Among the evaluated methods, IMS‐plating provided the best results regarding sensitivity and specificity for C. m. subsp. michiganensis detection, allowing the recovery of viable bacteria from seed extracts. Significance and impact of the study: IMS‐plating increases isolation rates of C. m. subsp. michiganensis and could improve standard protocols currently used for routine analysis.     

Seed treatment with lactic acid bacteria against seed-borne pathogens of spring wheat

Antifungal potential of lactic acid bacteria (LAB) such as Lactobacillus sakei KTU05-6, Pediococcus acidilactici KTU05-7 and Pediococcus pentosaceus KTU05-8, KTU05-9 and KTU05-10 was tested on naturally contaminated wheat seeds. LAB influence on fungal growth on kernels, seedling diseases and seed germination was examined by laboratory and field experiments. KTU05-10 was selected and later used for seed treatment as solitary strain and in two- or three-component mixtures with KTU05-7 and KTU05-6. The occurrence of Fusarium spp. on wheat kernels in agar plate assays was decreased by seed treatment with all LAB cultures, and the efficacy of each strain depended on incubation temperature. Inoculation of wheat kernels with strains of solitary KTU05-10 and in mixtures with KTU05-7 and KTU05-6 significantly reduced the incidence of Fusarium spp., Bipolaris sorokiniana and Alternaria spp. LAB influence on seed germination and seedling diseases was observed in laboratory and field experiments, but in most cases, this influence was insignificant.     

Use of composts to manage corky root disease in organic tomato production

Corky root disease of tomato caused by Pyrenochaeta lycopersici is an economically important disease in organic tomato production. This study aimed to evaluate the effects of various composts consisting of green manure, garden waste and horse manure against corky root disease through bioassay under greenhouse conditions, where soil naturally infested with P. lycopersici was used as a root substrate. The various composts were mixed at a rate of 20% (v/v) with the infested soil. Disease severity (measured as infected roots) in the unamended soil was compared with that in the soil–compost mixtures. One of the composts made from garden waste significantly reduced the disease, whereas horse manure compost significantly stimulated it. Lower concentrations of NH₄‐N and total carbon and a higher concentration of Ca in the substrate were correlated with lower level of corky root disease. Addition of green manure or garden waste compost to the infested soil increased total microbial activity or population density of copiotrophic bacteria and actinomycetes, respectively. However, increased microbial activity or microbial population in soil–compost mixtures was not associated with a reduction in corky root disease severity in the present study.     

The Effect of Chitinase on Didymella applanata, the Causal Agent of Raspberry Cane Spur light

In vitro and in vivo studies were conducted to assess the efficacy of the two microbial chitinases Chi I (from Streptomyces sp.) and Chi II (from Serratia marcescens) on Didymella applanata (Niessl.) Sacc., the fungus which causes spur blight of raspberry (Rubus idaeus L.). D. applanata was isolated from canes of diseased raspberries in a plantation in Novosibirsk, Russia. In vitro, the effective concentration of Chi I that reduced the growth of D. applanata was 0.4 U/ml (p = 0.05), but Chi II had no influence on the growth of the fungus in medium. In inoculation experiments on raspberry canes, both chitinases at the rate 0.5 U/ml reduced fungal development. In plantation where canes were inoculated after spraying with chitinase, fruiting bodies of fungus failed to form in all enzyme treatments, whereas a significant number of these fungal fruiting bodies (12.8 per cm²) developed in control treatments lacking chitinases spraying. The chitinases reduced the size of lesions and limited the infection of internal tissues of canes. Field testing of Chi I under natural conditions showed a significant suppression of the independent spur blight. These studies form the basis for further evaluation of ecologically benign control measures for raspberry spur blight.     

Transmission of seed-borne infection of chilli by Burkholderia solanacearum and effect of biological seed treatment on disease incidence

Abstract

A survey of chilli fields in the state of Karnataka, India, showed the presence of bacterial wilt disease in important chilli growing regions. The disease incidence ranged from 26?–?32%. The pathogen was isolated from infected plant material and seeds. Infected plant material showed the release of milky white bacterial ooze. Burkholderia solanacearum was detected from chilli seeds by liquid assay and its identity was confirmed by biochemical tests, hypersensitive reaction and pathogenicity tests. Seed transmission of the pathogen up to 45% was observed in seeds artificially infested with the pathogen. Among different tissues of the seed, endosperm showed the presence of the pathogen. Biological seed treatment with antagonistic Pseudomonas fluorescens significantly (p?=?0.05) improved the seed quality parameters under laboratory conditions and drastically reduced the bacterial wilt incidence under field conditions. Seed-borne nature, transmission and effect of Pseudomonas fluorescens in both the forms of pure culture and formulation on seed quality parameters and bacterial wilt incidence are discussed in the present work.     

Studies on seed-borne fungi of wheat in seed health testing programme

Seed mycoflora associated with wheat was studied on different media with a particular reference to Blotter and potato dextrose agar (PDA) procedures of ISTA. Seed-borne fungi, viz. Fusarium moniliforme, Rhizopus spp., Mucor spp., Alternaria alternata, Aspergillus niger, Aspergillus flavus, Curvularia lunata, Drechslera spp, Alternaria spp. and Penicillium spp., were isolated from the variety HD264. Blotter method was found to be the best media for the isolation of mycoflora whether borne externally or internally. Total number and frequency of occurrence of fungi were recorded. The effect of seed treatment with different chemicals and eco-friendly botanicals was analysed on germination, and growth, better percentage of seed germination and reduction in fungal pathogen were due to biochemical seed treatment.     

浙江番茄灰叶斑病病原菌

近年浙江省杭州市余杭区温室大棚内番茄灰叶斑病发生为害严重,对当地番茄生产造成了较大的经济损失,但该病害的病原菌种类尚未在浙江报道。本文通过对病原菌形态学、分子系统学（rDNA-ITS、gpd和EF-1α基因的PCR扩增、序列分析和系统进化树的构建）和致病性测定相结合的研究,将侵染番茄的病原菌鉴定为番茄匍柄霉菌Stemphylium lycopersici。研究结果对制定该病害的防治决策和有效防治提供了科学理论依据。     

温湿度对番茄刺皮瘿螨实验种群的影响

在同一湿度（53%RH）不同温度（14℃、17℃、20℃、23℃、26℃、29℃、32℃、35℃及同一温度（26℃）不同湿度（30%RH、53%RH、75.5%RH、85%RH、92.5%RH、100%RH）组合条件下,测定了温湿度对番茄刺皮瘿螨Aculops lycopersici (Massee)生长发育及繁殖的影响。结果表明,温、湿度对该螨存活率有明显影响,以23℃（53%RH）和75.5%RH（26℃）条件下最高,分别为89.9%和87.1%; 其发育历期较短,在14～35℃和30%～100%RH范围内,历期随温度升高而缩短,随湿度升高而延长; 番茄刺皮瘿螨的发育起点温度较高,卵、若螨和整个世代的发育起点温度分别为10.51、9.02和9.15℃。完成一代需要105.56日·度。温湿度对番茄刺皮瘿螨的繁殖力有明显影响,产卵期随温度升高而缩短,随湿度升高而延长; 产卵量在26℃(53%RH)和53%RH(26℃)下最高,每头雌虫产卵分别为44.3粒和42.2粒; 26℃(53%RH)和53%RH(26℃)条件下种群的内禀增长率最高,分别为0.2645和0.2669。结果表明,适宜的温湿度条件为温度26～29℃、相对湿度53%～75%。     

Incidence of seed-borne fungi and aflatoxins in Sudanese lentil seeds

Thirteen seed samples of lentil (Lens esculenta) were incubated on agar plate and moist filter papers (Moist Chambers) at 28 ± 2 °C for determination of the incidence of seed-borne fungi. Aflatoxins content of the seeds was measured using the bright greenish-yellow fluorescence test (BGYF) and thin-layer chromatography (TLC). Sixty-nine species and seven varieties, which belong to 24 genera of fungi, were isolated from this crop. Of these fungi, 51 species and two varieties are considered new for this crop, whereas seven genera and 13 species are new to the mycoflora of the Sudan. The genus Aspergillus (13 species and 6 varieties) which comprising 44% of the total colony count was the most prevalent genus followed by Rhizopus (2 species, 19%), Penicillium (6 species) and Fusarium (8 species) (12%), Chaetomium (3 species) and Cladosporium (5 species) (6%), where the 18 genera (1–4 species) showed very low level of incidence (19%). Of the possible pathogens of lentil plants, F. oxysporum the main cause of vascular wilt was recovered from seeds of this crop. Thin layer chromatographic analysis of chloroform extracts of 13 seed samples showed that only one samples was naturally contaminated with aflatoxins B₁, B₂, G₁ and G₂ (14.3 μg/kg). This revised version was published online in June 2006 with corrections to the Cover Date.     

The contribution of tomato and alternative host plants to tomato leaf curl virus inoculum pressure in different areas of South India

Indian tomato leaf curl virus (ToLCV) (Geminiviridae: Sub-group III) was detected both in field-collected and laboratory-reared B. tabaci using a triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). ToLCV was detected in six of the 10 group samples of field collected B. tabaci. ToLCV was also identified in 13 weed species commonly found in Karnataka, both by symptom expression and TAS-ELISA. ToLCV from c. 61% of infected plants was transmitted successfully to tomato by B. tabaci. Tomato plots were planted at three locations on the University of Agricultural Sciences Campus, Bangalore. Indian tomato leaf curl virus disease (ToLCVD) incidence increased most rapidly when the tomato plot was situated adjacent to an older ToLCVD-infected tomato field. When the plots were positioned in a dryland or a wetland area, at least 500 m away from any infected tomato fields, the ToLCVD incidence increased less rapidly, although in all sites it was 100% by 11 wk after transplanting. The numbers of B. tabaci caught on yellow traps in all sites increased during weeks 1–3 after transplanting and thereafter remained at between 10–15 adults trap^-1 24 h^_1. Adult numbers recorded on tomato plants by direct counts remained approximately constant at 2–4 adults plant“”¹. Tomato fields were planted in three taluks (administrative areas) of Karnataka, that had different current and previous histories of tomato production. ToLCVD incidence increased most and least rapidly, respectively, in Kolar taluk where tomato is grown continuously and Doddaballapur tuluk where tomato was grown in the area for the first time. In Malur tuluk, where tomato was grown discontinuously (once a year), the incidence of ToLCVD increased at an intermediate rate. Weed host-plant species growing near the experimental sites had averages of between 1.5–10.0 B. tabaci nymphs per plant, whereas the tomato plants had only 0.3 nymphs per plant. The percentage parasitism of B. tabaci nymphs on tomato and weed species, respectively, was 0.7% and 2–6%. Nymphs and pupae were parasitised by an Encarsia sp. and Eretmocerus mundus Mercet. The relevance and implications of these findings for the epidemiology and management of ToLCVD in Karnataka State, South India is discussed.     

Microconidia germination of the tomato pathogen Fusarium oxysporum in the presence of root exudates

Abstract

In this study we assessed microconidia germination of the tomato pathogens F. oxysporum f. sp. lycopersici (Fol) and F. oxysporum f. sp. radicis-lycopersici (Forl) in the presence of root exudates. Tomato root exudates stimulated microconidia germination and the level of stimulation was affected by plant age. Treatment of root exudates with insoluble polyvinylpolypyrrolidone, which binds phenolic compounds, indicated that tomato root exudates contain phenolic compounds inhibitory to F. oxysporum microconidia germination. Our study indicates that tomato root exudates similarly stimulate microconidia germination of both Fol and Forl. However, individual F. oxysporum strains differ in the degree of germination response to the root exudates. Furthermore, root exudates from non-host plants also contain compounds that stimulate microconidia germination of Fol. In general, the effects of root exudates from non-host plants did not differ considerably from those of tomato. The ability of phenolic compounds to inhibit germination of Fol seems not to be plant-specific.     

Cultural and physiological characteristics of Stemphylium lycopersici causing leaf blight disease on vegetable crops

During 2011–2012, an extensive leaf spot disease caused by Stemphylium lycopersici was observed on vegetable crops including, tomato, eggplant, pepper and lettuce in major vegetable-growing regions of Malaysia. Four isolates of S. lycopersici obtained from each vegetable crop were used to determine cultural and physiological characteristics. The variations were found in colony colour (pale to light grey or light as well as the brown), texture (cottony or mycelium flat), shape (regular with concentric growth rings or irregular) and pigmentation (yellow or deep red) of the cultures. The optimum temperature for the conidial germination and mean radial growth of the isolates was 25?°C, and the radial growth of the isolates was maximal on V-8 juice agar followed by potato carrot agar. The maximum sporulation of S. lycopersici isolates was observed on V-8 juice agar media under 12/12 h light/darkness photoperiod at 25?°C.     

Biological Control of Fusarium Wilt in Tomato Caused by Fusarium oxysporum f. sp. lycopersici by AMF Glomus intraradices and some Rhizobacteria

In the present study, the effects of the arbuscular mycorrhizal fungus (AMF) Glomus intraradices Schenck & Smith and four rhizobacteria (RB; 58/1 and D/2: Pseudomonas fluorescens biovar II; 17: P. putida; 21: Enterobacter cloacae), which are the important members of the rhizosphere microflora and biological control agents against plant diseases, were examined in the pathosystem of Fusarium oxysporum f. sp. lycopersici [(Sacc) Syd. et Hans] (FOL) and tomato with respect to morphological parameters (fresh and dry root weight) and phosphorous (P) concentration in the roots. Treatments with single and dual inoculation with G. intraradices and RB strains reduced disease severity by 8.6–58.6%. Individual bacteria inoculations were more effective than both the single AMF and dual (G. intraradices + RB) inoculations. In addition, the RB and G. intraradices enhanced dry root weight effectively. Significant increases in root weights were recorded particularly in the triple inoculations compared with single or dual inoculations. Compared with the non‐treated controls all biological control agents increased P‐content of treated roots of plants. Colonization with RB increased especially in triple (FOL + G. intraradices + RB) inoculations whereas colonization of G. intraradices was significantly decreased in treatment of FOL + G. intraradices compared with triple inoculations. The results suggest that suitable combinations of these biocontrol agents may ameliorate plant growth and health.     

番茄叶片理化性质差异与抗番茄刺皮瘿螨性

对3个不同类型番茄品系理化性状与番茄刺皮瘿螨Aculops lycopersici(Massee)的关系进行研究。结果表明,番茄刺皮瘿螨在多茸毛性状品系YZ618上种群数量最低,显著低于少茸毛性状品系YZ504和常规品系YZ413。螨在3品系植株分布不同,抗螨品系YZ618上部螨量几乎灭绝,感螨品系YZ504上部螨量显著多于中下部,常规品系YZ413上中部螨量多于下部。3品系叶组织内多酚氧化酶(polyphenol oxidase,PPO),过氧化物酶(peroxidase,POD),抗坏血酸过氧化酶(ascorbate peroxidase,ASP)的活性受该螨为害后均提高,但抗螨品系YZ618反应更灵敏。相关分析表明,PPO是螨害诱导产生的抗螨生化因子,ASP是植物本身具有的抗螨生化因子,POD与抗螨性的关系不大。     

Disease intensity of some tomato viroses in Serbia

In this paper we present the data on the disease intensity of the tomato plants grown in glass and plastic-houses, and in the open field. The infection was caused by the following viruses: Tomato mosaic virus (ToMV), Tobacco mosaic virus (TMV), Tomato spotted wilt virus (TSWV), Alfalfa mosaic virus (AMV), Potato virus X (PVX), Potato virus Y (PVY), Tomato black ring virus (TBRV), Tomato ringspot virus (ToRSV), Tomato aspermy virus (TAV), and Cucumber mosaic virus (CMV). These viruses represented most frequent tomato pathogens in Serbia. According to the obtained results, it could be concluded that 92.94% of the tested tomato plants grown in glass and plastic-houses, and 89.82% grown in the open field were infected by one of the above viruses. Most of the plant samples were infected by two or more viruses. The most frequent viruses — tomato pathogens in Serbia were ToMV, PVY and TMV.     

不同基因型番茄种子萌发期的耐盐性

选用14种不同基因型番茄进行萌芽期NaCl胁迫耐盐性筛选,对相对发芽势和相对发芽率两项指标进行聚类分析,将其划分为耐盐性强（5种）和耐盐性弱（9种）两类,从中选出4种耐盐性和生物性状不同的番茄(耐盐性强：野生醋栗番茄、小果型辽园红玛瑙、大果型红宝石;耐盐性弱：大果型辽园红多丽)分别进行不同种类钠盐以及NaCl、Na⁺、Cl^-两组胁迫试验.结果表明：4种不同基因型番茄对各种盐胁迫响应与NaCl的鉴定结果一致;不同Na⁺盐中碱性盐NaHCO₃对番茄的影响最大,在100 mmol·L^-1 Na⁺浓度下,4种基因型番茄的相对胚芽长度都在8%以下,5种盐对番茄种子萌发的抑制顺序为：NaNO₃2SO₄2PO₄3;NaCl、Na⁺、Cl^-胁迫下,Cl^-对番茄的伤害最小.