匍枝根霉和半裸镰刀菌侵染甜瓜果实产生的胞壁降解酶与侵染方式

 匍枝根霉(Rhizopus stolonifer)和半裸镰刀菌(Fusarium semitectum)以不同的机制侵染甜瓜果实。匍枝根霉侵染时,菌丝分泌大量的果胶甲酯酶(PME)、多聚半乳糖醛酸酶(PG)、果胶甲基半乳糖醛酸酶(PMG),迅速消解组织中胶层,引起细胞电解质外渗、质壁分离和软腐。菌丝在胞外和细胞间隙生长,不能穿透细胞壁。半裸镰刀菌侵染甜瓜果实时分泌高活力的果胶甲酯酶、果胶裂解酶类(PML)和纤维素酶(Celulase)而缺少果胶水解酶类,菌丝不能迅速消解中胶层,但以直接穿透细胞壁方式侵染组织细胞。这两种病原对甜瓜不同的致腐方式是由它们不同的外泌胞壁降解酶种类和酶学特性所决定的。     

长豇豆疫病的初步研究

 广州地区长豇豆普遍出现的"死藤"除了镰刀菌枯萎病外,疫病也是重要的病原。疫病病原菌经鉴定为Phytophthora vignae Purss。这一发现,对长豇豆抗枯萎病的育种工作具有重要的意义。Phytophthora vignae人工接种只危害豇豆属各个品种,但刺伤接种能侵染菜豆荚、茄子果实、马铃薯块茎;不能侵染大豆、绿豆、赤豆、豌豆、蚕豆、黄瓜、辣椒。在高菌量接种条件下,所参试的8个品种均不抗病,以"抗病二号"较好。盆栽药效试验以90%乙磷铝300倍液效果较好。喷药后即接种防效达90.81%。喷药3天后还有一定的效果,但接种24小时后再喷药,药效便可降低为51.33%。     

Fusarium crown and root rot of tomatoes in the UK

Fusarium crown and root rot caused by Fusarium oxysporum f. sp. radicis-lycopersici was found in the UK in 1988 and 1989 mainly in rockwool-grown tomato crops. Up to 14% of plants were affected in individual crops. In experiments, leaf and stem symptoms did not appear until the time of first fruit harvest even when the plants were inoculated at planting, first flowers or fruit set. Conidial inoculum at 10⁶ spores/plant applied at seed sowing killed 70–83% of tomato seedlings, whereas similar levels of inoculum applied to young plants caused root and basal stem decay, and eventually death but only after fruit harvest began. Disease incidence and symptom severity increased with inoculum concentration. Experimentally, the disease was more severe in peat- or compost-grown plants than in rockwool. Disease spread was only a few centimetres in 50 days in experimental rockwool-grown plants. All tomato cultivars tested were highly susceptible. Prochloraz-Mn was highly effective against the pathogen in vitro and controlled the disease in the glasshouse, but only when applied preventively. Non-pathogenic Fusarium oxysporum isolates and Trichoderma harzianum also reduced FCRR disease levels.     

Involvement of antifungal compounds from rockmelon fruit rind (<Emphasis Type="Italic">Cucumis melo</Emphasis> L.) in resistance against the fruit rot pathogen <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">melonis</Emphasis>.

Fusarium rot caused by Fusarium oxysporum f. sp. melonis, causes significant postharvest losses in rockmelon crops. Although latent infection is often present in the field, symptoms of the disease may not appear until fruit maturity. The susceptibility of different-aged rockmelon fruit cv. “Colorado” was determined by inoculating fruit at different stages of development with a spore suspension of F. oxysporum f. sp. melonis. Disease symptoms appeared first and were more severe in older fruit compared to younger fruit. Disease symptoms on fruit 35 DAA (Days After Anthesis) and 42 DAA appeared within 3 days of inoculation and rapidly covered the fruit within 5 days. In contrast, disease symptoms on fruit 7 DAA appeared 6 days after inoculation and grew slowly. Extraction of antifungal compounds without involving acid hydrolysis from 7 DAA fruit rind did not show antifungal activity on TLC plates. However, hydrolysis of the ethyl acetate fraction resulted in a strong fungal inhibitory zone on agar plates against colonies of F. oxysporum f. sp. melonis. Separation of the hydrolysed crude extracts on TLC plates indicated the presence of two distinct antifungal zones with R_f 0.36 and 0.13 in young fruit 7, 14 and 21 DAA. The area of fungal inhibition of compound R_f 0.36 was greater than that of R_f 0.13 on the TLC plate. Extracts from mature fruit of 35 and 42 DAA did not have detectable levels of antifungal compounds. The decrease in the susceptibility of rockmelon fruit during maturity may be correlated to a decrease in the antifungal compounds in the fruit with maturity.     

海南油棕果腐病的病原鉴定及发病条件的研究

三年来作者对于幼龄結果油棕的果穗和果实腐烂的症状、分布、蔓延为害,其发生条件和栽培管理的关系进行了詳細的調查和观察,并进行了病原分离、培养、田间人工接种和試探性化学保护等試驗。同时对果实离层組織的形成进行了切片检查。 結果指出海南十二个地区的幼龄结实棕园普遍出現的花、果、穗腐与环境条件和栽培管理有密切关系。果腐是果实离体后从蒂部組織开始的。从腐果組織中經常可以分离到細菌、炭疽菌和鐮刀菌。多次田間接种証明这些菌对健康果实和果穗均无致病能力。大田喷药无效。看来,油棕果腐病是由于环境坏、管理差的条件下,未成熟或接近成熟的果实产生离层而与果柄分离,再由外界杂菌腐食脫果而致腐烂。可見,本病是屬于非侵染性的生理病害。     

A fungal elicitor enhances the resistance of tomato fruit to Fusarium oxysporum infection by activating the phenylpropanoid metabolic pathway

Fungi infection in fruits is an important factor in postharvest losses. The effect of a treatment with a fungal elicitor on the response of tomato fruit to Fusarium oxysporum infection and changes in the phenylpropanoid metabolic pathway was studied. Fungal elicitor retarded for 3 days the development of the Fusarium rot development in tomato, at concentration of 2 g?l ^?1 (B2-F treatment). This treatment also induced a 3.11- and 6.03-fold increase of caffeic and chlorogenic acids, respectively, as compared with the control. Furthermore, the flavonoids naringenin-7-O-glucoside, rutin and kaempferol-3-O-glucoside, showed a greater abundance in tomato under the B2-F treatment after 6 days at 20°C. It is concluded that the fungal elicitor reduced the development of Fusarium rot by inducing the biosynthesis of metabolites from the phenylpropanoid metabolic pathway which forms part of the defense response in tomato fruit.     

万寿菊根提取物对西瓜枯萎病菌的抑菌活性成分及作用机理研究

本文研究了万寿菊根提取物中西瓜枯萎病菌的抑菌活性成分及其抑菌作用机理。结果表明,在4类主要化学物质中,精油类含量最高(59.8%),且抑菌效果最佳;10mg/mL精油提取物的抑制率在24、36和48h分别为62.83%,58.31%和56.30%。在西瓜枯萎病的3个主要发病期(苗期、伸蔓开花期和座果期)施用精油提取液,能有效抑制西瓜枯萎病菌,促进植株生长,同时提高西瓜植株的POD和SOD酶活性,并维持CAT活性,有效减轻了西瓜枯萎病菌对植株的毒害作用。     

The infestation of tomato seed by Fusarium oxysporum f.sp. radicis-lycopersici

The infestation of seed by Fusarium oxysporum f.sp. radicis-lycopersici occurred at rates of 0-1 to 0-01 % in fruit on stem-infected plants. Direct infection of fruit in the flower or young developing fruit stage resulted in a grayish-brown lesion on the stylar end of the fruit or mummification. F. oxysporum f.sp. radicis-lycopersici was isolated from all seeds in such fruit. Picked fruit inoculated on the stem scar also became infected but 96 h after inoculation of the fruit, the seed was not infested or infected. The contact of clean seed with hands that had previously handled F. oxysporum f.sp. radicis-lycoperisid-infesied sawdust resulted in a high level of seed infestation. The fungus survived on seed sent across Canada and stored for up to 12 weeks. Treatment with NaOCl or 0·1 N HCl did not completely disinfest infested seed.     

Impact of soil chemistry,nutrient supplements,and fungicides on the health and yield of field-grown processing tomatoes

We report the results of a 3-year study in which we collected and analyzed soil and yield data from experimental plots in six commercial processing tomato fields in Yolo and Solano counties in California. Our objective was to assess the effect of soil chemistry and soil-delivered nutrients and fungicides on tomato plant health and fruit yield at harvest. Marketable yield, leaf necrosis, and fruit loss due to sunburn differed significantly between individual fields, with averages ranging from 81.2–138.5 Mg ha^?1, 32–72% leaf necrosis and 1.9 to 8.8% sunburnt fruit, respectively. Higher-yielding fields showed significantly lower levels of leaf necrosis and sunburn damage and a positive correlation with pre-plant soil parameters such as potassium concentration and cation exchange capacity (CEC). Interestingly, soil amendments of composted poultry manure or other nutrient supplements in low-CEC fields, but not high-CEC fields, resulted in higher fruit yield and less leaf necrosis. While all fields showed symptoms typical of Verticillium wilt and some fields showed symptoms of Fusarium wilt, Fusarium crown and root rot, corky root, and root knot nematode, none of our soil amendments, including chemical and biological fungicides, significantly or consistently reduced incidence or severity of these diseases. We discuss our findings in the context of premature vine decline of tomato, an emerging phenomenon in production fields in the Sacramento Valley, which is characterized by the loss of plant vigor and canopy cover at the onset of fruit ripening and for which causative agent(s) and management options in California remain elusive. (247 words).     

Fusarium wilt of common heliotrope (heliotropium europaeum)

Occurrence of Fusarium wilt of common heliotrope(Heliotropium europaeum L.) is reported. Pathogenicity of the causal agent was confirmed by reisolation from inoculated heliotrope plants. The specificity of the isolate was shown by cross-inoculation tests with five formae speciales and by inoculating the five respective hosts with a monoconidial isolate of the present fungus. Only the latter fungus was found to incite wilt in common heliotrope; the proposed name of this forma specialis isFusarium oxysporum f. sp.heliotropae nov. f.     

Efficacy of certain antibiotics in the control of Postharvest Decay of Papaya Fruits

Evaluations were made of four antibiotics,viz., ampicillin, griseofulvin, aureofungin and mycostatin, againstAlternaria tenuis, Chaetomium globosum, Curvularia lunata, Cylindrocarpon tonkinense, Fusarium oxysporum andHelminthosporium spiciferum causing postharvest fruit rots of papaya (Carica papaya L.). A fruit dip treatment in 1000 ppm of aureofungin proved to be the most effective in controlling rots due to the above organisms, with mycostatin (1000 ppm) second best.     

Downy mildew-, powdery mildew- and fusarium wilt-resistant muskmelon breeding line PI-124111F

A muskmelon (Cucumis melo L.) breeding line, PI-124111F, is a seventh-generation selection derived from PI-124111, which is resistant to downy mildew (Pseudoperonospora cubenis pathotype 3), powdery mildew (races 1 and 2 ofSphaerotheca fuliginea) and Fusarium wilt (Fusarium oxysporum f. sp.melonis, races 0, 1 and 2). This is the only breeding line known to carry multiple-race resistance to these diseases. PI-12411IF is a monoecious muskmelon with poor fruit characteristics.     

Seed-borne fungi detected in consignments of soybean seeds (Glycine max) imported into India

Inspection of 16 017 samples of soybean seeds imported into India from 1978 to 2004 resulted in the detection of 21 pathogens, including Peronospora manshurica which is not present in India. Seed-borne fungi of high economic significance included: Ascochyta sojicola , Botryotinia fuckeliana , Cercospora kikuchii , Colletotrichum dematium , Corynespora cassicola , Diaporthe phaseolorum var . sojae , Fusarium oxysporum, Glomerella cingulata , Glomerella glycines , Macrophomina phaseolina , Nectria haematococca , Passalora sojina , Thanatephorus cucumeris as well as other fungal pathogens for which soybean is not a host such as Alternaria padwickii , Cochliobolus sativus , Fusarium culmorum , Fusarium poae , Glomerella graminicola , Setosphaeria rostrata, Verticillium albo-atrum , etc. Some of the fungi detected have very wide host range. Details are presented on the fungi detected, the countries from which the imported consignments originated, and phytosanitary significance.     

Reduction of postharvest losses of Galia melon by a short hot-water rinse

A rapid method for simultaneously rinsing and disinfecting fresh harvested produce using a hot-water rinse and brushes (HWRB) was tested on Galia melon ( Cucumis melo cv. reticulatus ) fruit. The optimal treatment to reduce decay while maintaining fruit quality after prolonged storage and marketing simulation was 59 ± 1°C for 15 s. Trial shipments by sea transport to Europe demonstrated that treating melon with a commercial-scale HWRB machine (3 tonnes fruit h⁻¹) maintained significantly better overall quality of treated fruit compared with untreated fruit. Exposing spores of Alternaria alternata and Fusarium solani to 60°C for about 15 s in vitro reduced germination by 48% and 42%, respectively. Employing HWRB resulted in a 3-log reduction in total colony-forming units (CFU) of the epiphytic microbial population, compared with untreated fruit. Scanning electron microscopy (SEM) showed that HWRB removed soil, dust and fungal spores from the fruit surface, and partially or entirely sealed natural openings in the epidermis.     

Allelochemical resistance traits of muskmelon (Cucumis melo) against the fruit fly (Bactrocera cucurbitae) in a hot arid region of India

Host plant resistance is an important component for management of the melon fruit fly, Bactrocera cucurbitae (Coquillett), owing to difficulties associated with its chemical and biological control. Various biochemical traits including total sugar, reducing sugar, non-reducing sugar, tannins, phenols, alkaloids, flavinoid and pH contents of fruit were studied on 11varieties/ genotypes of muskmelon, Cucumis melo L., in relation to resistance against B. cucurbitae under field conditions. Significant differences were found in tested varieties/ genotypes for fruit infestation and larval density per fruit. AHMM/BR-1, RM-50 and AHMM/BR-8 were the most resistant; MHY-5, Durgapura Madhu and Pusa Sarabati were moderately resistant; AHMM/BR-13, Pusa Madhuras and Arka Jeet were susceptible; whereas Arka Rajhans and GMM-3 were the highly susceptible varieties/ genotypes to fruit fly in both seasons, 2011 and 2012. The larval density per fruit increased with an increase in percent fruit infestation and there was a significant positive correlation (r = 0.97) between percent fruit infestation and larval density per fruit. Total sugar, reducing sugar, non-reducing sugar and pH were lowest in resistant and highest in susceptible varieties/ genotypes, whereas tannins, phenols, alkaloids and flavinoid contents were highest in resistant and lowest in susceptible varieties/ genotypes. Total alkaloid and pH contents explained 97.96% of the total variation in fruit fly infestation and 92.83% of the total variation in larval density per fruit due to alkaloids and total sugar contents.     

Fusarium stem and fruit rot of sweet peppers in the glasshouse

A stem and fruit rot of sweet peppers ( Capsicum annuum ) occurred in 1992 in West Sussex affecting a large proportion of plants of cv. Tasty and to a lesser extent cv. Mazurka. Fusarium solani was isolated from the stem lesions and also from a short distance above and below them. The disease was largely nodal. Distinctive fruit symptoms also occurred. Symptoms were reproduced by inoculation of wounds on the stem. On agar and in a small in vivo test the pathogen was sensitise to benomyl at 2 μg ml. The disinfectants, commercial sodium hypochlorite, Purogene and Tego 51 effectively killed macrospores following exposure for 15 min.     

Trypetidae (non-European)

This data sheet covers only the non-European fruit flies (Diptera: Tephritidae [= Trypetidae]). It does not cover the many gall-forming and other species that feed in the vegetative parts of plants. The fruit flies presenting a phytosanitary risk to EPPO countries fall into two principal groups: cool temperate species mostly capable of diapausing and usually univoltine, and warm temperate or tropical species mostly capable of continuous breeding apparently without diapause. This data sheet presents information on Rhagoletts pomonella and Dacus tryoni as representatives of the first and second groups respectively, together with references to other species where appropriate.     

韭菜对巴西香蕉枯萎病发生的抑制作用

采取田间试验、盆栽试验及实验室研究相结合的方法,研究了韭菜对香蕉枯萎病的防控效果。田间试验表明,韭菜之后轮作香蕉,第1年香蕉枯萎病平均发病率仅为1.73%（对照为52%）。盆栽试验表明,韭菜处理对香蕉枯萎病发病抑制率为85.9%,病情抑制率为82%;而且韭菜叶片的水提取液对香蕉枯萎病菌（Fusarium oxysporum f.sp.cubense,FOC）孢子增殖抑制率为91.2%,对其致死率为86.97%。本研究表明,韭菜轮作香蕉的种植模式是一种防控香蕉枯萎病的有效途径,而且韭菜及其制剂有望发展成为防控香蕉枯萎病的环境友好型的新型生物试剂。     

Effects of 2-chloroethylphosphonic acid (Ethrel) on gooseberries

Solutions of 2-chloroethylphosphonic acid (Ethrel) up to 480 parts/million concentration were applied as foliar sprays to gooseberries (cv. Careless). Harvesting consisted of shaking the bushes by hand and collecting the dropped fruit. With increasing CEPA level pre-harvest fruit abscission increased and amount of fruit finally left on the bushes decreased. Splitting the application had the effect of reducing pre-harvest abscission. Berry size and total yield were not significantly affected by any of the treatments. Taste-panels did not detect any off-flavours in treated fruit. At hard green fruit stage, analyses for shear value, colour, acidity and soluble solids did not show any marked treatment effects. At ripe fruit stage, softening, yellowing and decrease in acidity were significantly greater for the 480 parts/million CEPA level than for the other treatments. There were no signs of phytotoxic or carry-over effects due to CEPA.     

First record of Rhagoletis cingulata (Loew) (Dipt., Tephritidae) in Austria

The Nearctic eastern cherry fruit fly species Rhagoletis cingulata (Loew) (Dipt., Tephritidae) has been detected several times in different European countries during the last decades. This species as well as Rhagoletis indifferens (Curran) are major pests of cultivated cherries in North America and are classified as quarantine pests in Europe. The introduction and establishment of both species could result in severe problems for Austrian cherry production due to additional infestation pressure caused by overlapping developmental cycles of American and native cherry fruit flies. A survey of both non-European cherry fruit fly species was carried out during the growing seasons of 2007 and 2008 at eleven sampling sites in the eastern part of Austria. Pherocon^® AM yellow sticky traps were installed in cherry trees and replaced at weekly or fortnightly intervals. Identification of the cherry fruit flies caught was based on morphological characteristics. Two specimens of R. cingulata were caught in 2007 in different weeks and at different locations while none were caught in 2008. R. indifferens was not detected at all. While it is possible that these specimens originate from established populations with low densities, it is more likely that the catches derived from accidental introductions.