bluuebunny/crossref_metadata_2025 huggingface dataset:
Successful eradication of Ralstonia solanacearum from Sweden1
Authors: PERSSON P.
Published: April 2008

Ralstonia solanacearum was detected in potato tubers from two separate localities in southern Sweden over the period 1972/1977. Investigations were made to trace the origin of the pathogen. All infected tubers were found to be produced in irrigated fields. Solanum dulcamara, growing close to or in stream water used for irrigation, was found to be infected. Small roots growing in the water contained high populations of R. solanacearum. Infected plants were located downstream where a potato industry had formerly been situated. Stream water from both outbreak localities was found to be contaminated. A programme to eradicate S. dulcamara growing in the contaminated stream Pinnån was started in the late 1970s. Exemption was given for the herbicide glyphosate which was used, together with mechanical treatment, along a distance of 30 km. The areas infested in the 1970s have recently been screened again for R. solanacearum in S. dulcamara and in stream water and the bacterium has not been detected. A survey of streams and sewage dams near potato processing plants, and of streams used for irrigation, has been made in southern Sweden without any detection of R. solanacearum. Selected lots of seed potatoes have been tested for latent infections in 1995 and 1996. All samples were found negative. R. solanacearum has been successfully eradicated from Sweden.
A review of secondary‐poisoning studies with rodenticides
Authors: JOERMANN G.
Published: April 2008

Rodenticides can become a danger for predators and scavengers if they prey on dead or moribund rodents. One possibility for assessing the hazard potential is to conduct trials in which poisoned rodents are fed to predators. Over the years, numerous such studies have been carried out with a wide range of carnivorous mammals and birds. Since an internationally recognized standard method only recently came into existence, the studies differ in details of trial procedure. The most significant end point is the mortality rate; in addition, blood clotting response often serves as a biomarker. This review includes studies on brodifacoum, bromadiolone, chlorophacinone, coumatetralyl, difenacoum, flocoumafen, warfarin and zinc phosphide which have been published in the open literature or which have been submitted by industry in the authorization procedure for plant protection products.
Viruses and virus diseases of grapevine in Palestine
Authors: ALKOWNI R. , DIGIARO M. , SAVINO V.
Published: April 2008

Surveys were carried out in vineyards in the main grapevine‐growing areas of Palestine (Hebron, Bethlehem, Gaza, Jerusalem, Ramallah, Jenin, Jericho and Nablus) to assess the presence and incidence of virus and virus‐like diseases. Leafroll symptoms were observed in Bethlehem, Ramallah and Jerusalem in native and imported cultivars, with higher rates in the red‐fruited Shami, Beitoni and Smari. Rugose‐wood symptoms were also observed in local and foreign cultivars, especially on grafted vines with a high incidence in Bethlehem. Fanleaf symptoms were rarely observed, while phytoplasma‐induced symptoms were observed in Jenin, Jericho and Bethlehem on cvs Biadi, Superior Seedless and Beitoni. ELISA tests showed that 463 out of 566 (82%) tested vines were infected by at least one virus. GVA was the prevailing virus (66.1%), followed by GLRaV‐1 (45.6%), GLRaV‐3 (21.7%), GFkV (15.7%) and GLRaV‐2 (8.3%). GVB and GFLV were also detected to a lesser extent, their incidence ranging between 3.7 and 1.2%, whereas GLRaV‐7 was detected in a single vine of cv. Sultanina of foreign origin. Vineyards in the Bethlehem area were particularly badly damaged (97.5%), and some local cultivars were totally (Jandali, Marrawi and Shoyoukhi) or heavily infected (Zaini, Biadi and Shami). ELISA testing of 69 young rootstock mother plants showed a relatively high incidence of virus infection (20.3%). Vein necrosis and vein mosaic diseases were also ascertained on graft‐inoculated 110R and Vitis riparia indicator plants, whereas no viruses other than GFLV were mechanically transmitted from about 200 vines onto inoculated herbaceous hosts.
Systems for control of Leptinotarsa decemlineata preventing development of resistance1
Authors: HERTELENDY L.
Published: April 2008

Combining products with different modes of action is one approach to preventing the development of insecticide resistance in Leptinotarsa decemlineata. Suitable combinations of active substances are proposed.
Future management of internal quarantine pests of potato in Ukraine1
Authors: OMELYUTA V. P.
Published: April 2008

A strictly regulatory approach has been taken in the past with respect to quarantine pests present with limited distribution in Ukraine. Leptinotarsa decemlineata had at one time this status, but the regulatory strategy against it was not successful, the pest became widespread and was deleted from the quarantine list. It is suggested that an approach based on pest risk analysis, relating the management strategy more closely to the risk specifically arising from each pest, could be more successful in future against the principal internal quarantine pests of potato in Ukraine: Phthorimaea operculella, Globodera rostochiensis and Synchytrium endobioticum.
National control measures for Clavibacter michiganensis subsp. sepedonicus1
Authors: McNAMARA D. G. , SMITH I. M.
Published: April 2008

Clavibacter michiganensis subsp. sepedonicus has a clearly restricted geographical distribution in the EPPO region, being present almost exclusively in the north and east. Countries where it is absent take strong phytosanitary measures to prevent its introduction. Within the European Union, countries where it is present aim to eradicate the disease. The EU Control Directive for ring rot puts in place community‐wide measures for surveillance, containment and eradication.
National control measures for Synchytrium endobioticum1
Authors: McNAMARA D. G. , SMITH I. M.
Published: April 2008

Although Synchytrium endobioticum has been found in almost all potato‐growing countries of the EPPO region, it is absent from the great majority of fields. A few plots scattered across the potato‐growing areas have been ‘scheduled’ as infested but potatoes are not grown on them. The disease is accordingly hardly ever seen. This is the result of continent‐wide multiyear campaign of potato wart control within countries, according to which it is prohibited to grow potatoes on infested plots, and only resistant cultivars may be grown in a safety zone around them. S. endobioticum can persist for several decades in soil, as resting spores, but it is now dying out in plots that have been subject to the control campaign for a sufficiently long period. Procedures are now being agreed for officially ‘descheduling’ such plots.
Procedures for the settlement of disputes concerning phytosanitary measures
Authors: Hedley J.
Published: April 2008

The situation regarding the resolution of phytosanitary disputes has changed considerably with the introduction of the World Trade Organization (WTO) Agreement on SPS Measures and the approval of the 1997 revised IPPC by the 29th FAO Conference. In understanding the issues involved in dispute settlement, it is helpful to consider: a general outline of dispute resolution procedures; the problems inherent in the mechanics of dispute settlement and the technicalities of phytosanitary measures in resolving phytosanitary disputes; the current means of resolving phytosanitary disputes, including the use of consultation and a committee of experts, as described in the 1997 revised IPPC, and the dispute settlement body of the WTO; the ways of dealing with the problems, including consideration of the level and nature of the dispute, the international character of such disputes, the nature of the decision (recommendatory or binding), the organization of the resolution system and the systems available. It is suggested that the Interim Commission on Phytosanitary Measures could take a role in this area, with a committee on dispute resolution that considered dispute resolution procedures, to aid parties in dealing with the difficulties involved in the resolution of phytosanitary disputes.
Glasshouse quarantine pests for the EPPO region and measures recommended by EPPO and the EU to prevent their spread1
Authors: Smith I. M.
Published: April 2008

The EPPO A1 and A2 quarantine lists (with corresponding specific quarantine requirements) and Annexes I and II of EU Directive 77/93 (with requirements in Annex IV) cover a number of important glasshouse quarantine pests: Liriomyza spp., Bemisia tabaci and the viruses it transmits, Frankliniella occidentalis, tomato spotted wilt tospovirus, Thrips palmi, Aculops fuchsiae, Helicoverpa and Spodoptera spp., Opogona sacchari and Radopholus similis. Most frequently, the requirements made to exporting countries for these pests centre on country or area freedom, place of production freedom (usually over the last growing season), treatment of plants immediately before dispatch. Because many of the plants concerned have a wide host range, there is some difficulty in deciding which plant species should be regulated, or whether cut flowers, fruits or vegetables should be regulated as well as plants for planting. The requirements for some of these glasshouse pests are among the broadest included in the EPPO and EU system (e.g. all plants for planting, except seeds and bulbs, for T. palmi). The recommended requirements are generally well harmonized between EPPO and the EU, except in respect of the categories of exporting countries considered. The EU requirements frequently put neighbouring non‐EU European or Mediterranean countries on the same basis as the most remote continents. Such an approach does not seem justifiable to EPPO.
Quarantine pests intercepted in consignments of ornamental plants imported into Poland in 1993/19981
Authors: Karnkowski W.
Published: April 2008

During inspections of consignments of ornamental plants (cuttings, bulbs, rhizomes, pot plants, cut flowers) imported into Poland in 1993/1998, the following quarantine pests were intercepted most frequently: Frankliniella occidentalis (32 consignments), Aphelenchoides fragariae (17), Steneotarsonemus laticeps (12) and Bemisia tabaci (11). These pests were found in plants for planting, pot plants and cut flowers imported mainly from The Netherlands. Thrips palmi (EPPO A1 list) was intercepted on orchid cut flowers from Thailand (2) and Cacoecimorpha pronubana on pot plants of Thuja occidentalis from The Netherlands. Ditylenchus destructor was intercepted on bulbs of Erythronium denscanis (not previously described as a host). The methods of inspection and identification of particular intercepted pests are presented.
Quarantine glasshouse pests in Poland and their control1
Authors: Baranowski T. , Dankowska E. G.
Published: April 2008

The new Polish quarantine list has been operative since 1995. It consists of two parts: list A comprises organisms prohibited for import; list B consists of plants, plant products and harmful articles and organisms whose import is prohibited. Some of the pests in list A have occurred in Poland. Methods of controlling these species are presented in this paper.
Occurrence of tomato spotted wilt tospovirus in horticultural crops and weeds in the Czech Republic in 1992/19971
Authors: Mertelík J. , Mokrá V.
Published: April 2008

Tomato spotted wilt tospovirus (TSWV) was found in 1992 in three glasshouses in the Czech Republic. Although the infected plants were destroyed, the virus was detected later in other glasshouses infested with Frankliniella occidentalis. The virus was identified on the basis of host range, enzyme‐linked immunosorbent assay (ELISA) and electron microscopy. The ornamental plant species most frequently infected with TSWV were Dendranthema morifolium and Zantedeschia sp. With regard to vegetable crops, TSWV infection was frequently detected in tomatoes and capsicums. The common weed hosts were Stellaria media and Galinsoga parviflora.
Infectious diseases and certification of olive: an overview
Authors: Martelli G. P.
Published: April 2008

An account is given of diseases of olive (Olea europaea var. sativa) and related pathogens transmitted with propagation material, with special reference to viruses and phytoplasmas. To date, 14 virus and virus‐like diseases have been described and 12 different viruses and five phytoplasmas have been identified in symptomatic or symptomless plants. A brief description of the diseases is given, along with information on epidemiology and diagnosis. Possible remedies, such as sanitary selection, sanitation and implementation of certification schemes are discussed.
Crown rot caused by Phytophthora cactorum in Norwegian strawberry production
Authors: Stensvand A. , Herrero M. L. , Talgø V.
Published: April 2008

Crown rot of strawberry, caused by Phytophthora cactorum, was detected for the first time in Norway in 1992. This paper reports on surveys for P. cactorum in Norwegian certified strawberry plant production and on the distribution of the pathogen in regular strawberry production. In 1996 and 1997, samples of plant material from all certified strawberry plant growers in the country were investigated by isolation on artificial growth medium and using an enzyme‐linked immunosorbent assay (ELISA). P. cactorum was not detected in any of the samples. A total of 171 isolations from plants with symptoms resembling crown rot were made from plants in a survey of the distribution of Phytophthora fragariae var. fragariae and from other samples. P. cactorum was detected at 35 different strawberry‐producing farms in 11 of the 19 counties of Norway. The fungus was most frequently isolated from cv. Korona (at 18 locations), followed by cv. Inga (at 10 locations).
Identification and incidence of virus diseases of Capsicum annuum in the Lusaka Province of Zambia
Authors: Ndunguru J. , Kapooria R.G.
Published: April 2008

Commercial capsicum fields in Lusaka Province were surveyed for the presence of viruses during 1996‐01/06. The survey demonstrated the occurrence of five viruses in 13 fields. Virus identification was based on field disease syndrome, host range studies, DAS‐ELISA and electron microscopy. The identified viruses were alfalfa mosaic alfamovirus (AMV), potato Y potyvirus (PVY), tobacco mosaic tobamovirus (TMV), cucumber mosaic cucumovirus (CMV) and pepper mild mottle tobamovirus (PMMV). The most prevalent and widespread virus, recovered from 70% of the surveyed fields, was AMV, and this was followed by PVY and TMV, which were detected in 50% and 40% of the fields respectively. CMV and PMMV were less common and occurred in 30% of fields. The study also showed that PVY could infect capsicum plants alone or in combination with CMV or TMV. The average plant infections caused by AMV was 80–100% and by TMV and PVY 50% and 60% respectively. The disease incidence in the case of CMV was 15–60% and for PMMV 30–40%. This is a first report on the identification of viruses that infect capsicum in Zambia.
Caractérisation des souches de Pyrenophora teres et Pyrenophora graminea par analyse des protéines
Authors: Benkada M. Youcef , Barrault G. , Lotmani B. , Fellahi A. , Albertini L.
Published: April 2008

L'analyse des protéines mycéliennes par électrophorèse sur gel de polyacrylamide en conditions dénaturantes montre que les protéines solubles ne permettent pas de distinguer les différentes souches de Pyrenophora. En revanche, les bandes polypeptidiques spécifiques observées à travers l'étude des protéines pariétales ont permis non seulement de discriminer Pyrenophora teres f. teres de Pyrenophora teres f. maculata, mais également Pyrenophora teres de P. graminea. Enfin l'étude des profils isoenzymatiques fournit également des marqueurs biochimiques très intéressants. Les α‐estérases permettent de différencier les souches appartenant à la forme maculata. Les β‐estérases et les phosphoglucoisomérases offrent la possibilité d'une distinction interspécifique entre P. teres et P. graminea.
A new leaf spot disease of Cuphea spp. caused by Chaetomella raphigera
Authors: Singh H.B. , Johri J.K. , Singh M. , Singh A. , Tripathi A. , Singh S.P.
Published: April 2008

A new leaf spot disease of Cuphea spp., an emerging oilseed crop, was observed in the experimental fields of the National Botanical Research Institute, Lucknow, India. The pathogen was isolated and identified as Chaetomella raphigera.
Ustilago scitaminea au Maroc: maîtrise d'une maladie de quarantaine
Authors: Nadif A. , Akalach M.
Published: April 2008

La canne à sucre au Maroc a été confrontée en 1993 à l'un des principaux défis qui puisse menacer sérieusement son existence: le charbon dûàUstilago scitaminea. Cette maladie a sévi à un moment où les deux périmètres canniers du Royaume (Gharb et Loukkos) étaient plantés dans leur quasi totalité par des cultivars assez sensibles. Le présent article relate les efforts déployés par le Centre Technique des Cultures Sucrières (CTCS) en matière de lutte contre ce redoutable champignon et expose les principaux résultats qui ont conduit à une maîtrise de l'épidémie et son maintien au dessous du seuil économique tolerable.
The status of warning services for plant pests in Italy*
Authors: Rossi V. , Ponti I. , Cravedi P.
Published: April 2008

A survey of the present status of warning services for plant protection in Italy shows the lack of a national project, so that the different regional governments approach the question in different ways. In spite of this, some common characters are present: (1) most of the regions manage the warning service directly; (2) everywhere, the warning service interacts with research institutes, farmers’ associations, agrometeorological networks and other warning services; (3)‘indirect warning’ is the prevalent model of organization; geographical areas are divided into homogeneous subareas, where information useful for producing advice is collected and elaborated; warnings are then disseminated by different means of communication, and farmers comply with them autonomously; (4) warnings are usually prepared by a team of advisers, who meet periodically, analyse available information and elaborate suggestions for crop protection; (5) available information comes from field monitoring, weather stations, insect and spore traps, forecasting models for pests and diseases; unfortunately, forecasting models are not widespread; (6) the content of warnings is rather uniform, including information on crops, pests and diseases, suggestions for control strategies and, frequently, meteorological conditions and forecasts; (7) different means are used to disseminate warnings to farmers; usually several methods co‐exist: bulletins published in local newspapers, sent by mail or fax, displayed on notice boards or available via the Internet; placards; telephone messages; surveys on local TV or radio.
Structure and organization of warning services in Rheinland‐Pfalz (Germany)*
Authors: Jörg E.
Published: April 2008

Rheinland‐Pfalz, a federal state in the south‐western part of Germany, is an agricultural region with high crop diversity. For each branch of agriculture (arable, fruits, vegetables and ornamental plants), specific warning and information services have been installed. Advisory work, including warning services, is done by a central (LPP) and eight regional state institutions (SL V As). LPP provides the infrastructure for information dissemination, organizes data acquisition and supplies the farmers with general information on crop protection (availability of plant protection products, control strategies, etc.), SL V As collect data on current pest development and elaborate regional recommendations on field assessments and control measures to be taken by the farmers. Warning service information is transmitted to the farmers by info post (periodic letters), telephone‐answering machines, fax services and, lately, via the Internet. Farmers are mainly interested in current disease and pest severity data, preferably on a local basis, to aid their decision‐making in crop protection. The forecasting models and computer‐aided decision‐support systems run by the state crop protection service have become essential tools during the last four years. Their results, supplemented by field‐monitoring data, serve as the main input for the warning services. The Internet, in conjunction with computerized decision‐support systems, provides the means of ensuring an adequate supply of warning service information at a time when crop protection services are undergoing severe staff reductions.
Forecasting and warning system in Lithuania*
Authors: Gošovskiené J.
Published: April 2008

The State Plant Protection Service is responsible for the forecasting and warning system in Lithuania. The service collaborates with scientists from the Lithuanian Institute of Agriculture and Institute of Horticulture with respect to the methodology for forecasting and warning systems.
Overview of pest warning systems in Canada*
Authors: Favrin R. J.
Published: April 2008

The pest warning systems operated in the different provinces of Canada are reviewed.
Decision aids for apple scab warning services (Venturia inaequalis) in Germany*
Authors: Hindorf H. , Rövekamp I. F. , Henseler K.
Published: April 2008

Apple scab (Venturia inaequalis) represents the most serious pathogen and disease in orchards worldwide and has to be treated with a number of fungicides available on the market. In Germany, prophylactic application schedules have been banished in the past because of the availability of several commercial systems that forecast infection risk precisely. Experience with decision aids such as HP‐100, Welte, METOS and RIMpro in the Rheinland region of Germany in 1998/99 is presented and discussed. All systems serve as decision aids for forecasting potential infection periods, but do not provide a season‐long forecasting system based on data obtained 3–6 months in advance.
The Dutch approach: a combination of meteo‐based decision‐support systems*
Authors: Bouma E.
Published: April 2008

Reduction in the amount of active substance and reduced dependence on chemical plant production products are the main items in the Dutch Government Multiyear Crop Protection Plan. There are problems in reaching this goal, as weather conditions in The Netherlands are very beneficial to all kinds of fungal diseases. Such diseases have to be controlled by applications of preventive fungicides, and it is quite regular to use a spray interval of 6–7 days. Another problem is application at the wrong time. With the help of decision‐support systems (DSSs), it is possible to calculate the period of protection by a product, the danger of an infection period and the moment of highest efficacy. DLV‐Meteo offers advice based on five DSSs for individual pests (Prophy, onion leaf spot disease, Botrypré, Mycos and Contapré) and on a general DSS for application at the time of day that ensures highest efficacy (Gewis).
Development and implementation of cost‐effective plant protection technology using decision‐support systems in Lithuania*
Authors: Tamošiunas K. , Semašskiené R. , Dabkevičius Z.
Published: April 2008

In many European countries, factors important for decision‐making in plant protection, such as biology, weather and environmental conditions, crop management level and their relationships, have been incorporated into decision‐support systems (DSSs). In 1996, a project was jointly elaborated, and research was started by the Danish Institute of Plant and Soil Science, the Lithuanian Institute of Agriculture and the Lithuanian and Danish Agricultural Advisory Services. This research was focused on the testing, development and adaptation of a Danish computer‐based decision‐support and information system (PC‐Plant Protection) for plant protection under Lithuanian conditions. Trials were carried out by the Lithuanian Institute of Agriculture in 1996/1998 to investigate the potential for reducing fungicide inputs in cereal production in different regions of Lithuania representing typical local agrometeorological conditions. On the basis of the trials, the following conclusions were drawn: the reduced doses and fungicide combinations recommended by the DSS gave rather good control of diseases; spraying according to the recommendations of the DSS increased yield significantly in all experiments and allowed saving in fungicides; some models, e.g. for Leptosphaeria nodorum, were not fully suitable for Lithuanian conditions and need to be developed further.
Warning system in Portugal – organization and technical basis of forecasting*
Authors: Rosa T.
Published: April 2008

The forecasting and warning system in Portugal started in 1964 with a control programme applied against Plasmopara viticola, the most important pathogen of grapevine. Since then, studies and new techniques have been developed and applied to other important pests of vineyards and orchards, on the basis of epidemiological and climatic data that supports technical evaluation of the risk. In the last few years, mathematical models have been evaluated as an important part of the control strategy, integrated with biological data from field monitoring. At the moment, forecasting models are available for Plasmopara viticola, Venturia pirina, Venturia inaequalis and Cydia pomonella. The integration of forecasting models with field observations is used to formulate warnings that are sent out to farmers about the need to spray or not.
Computer simulation of the population dynamics ofPanonychus ulmiand applications to integrated pest management*
Authors: Sobala M.
Published: April 2008

Panonychus ulmiis a serious pest of apple orchards, especially in hot dry years. To improve quantitative insight into its population dynamics, and as a tool for forecasting optimal dates for visual assessment of abundance and of integrated pest management strategies, an age‐ and stage‐structured temperature‐dependent predator–prey model forP. ulmiand two of its natural enemies,Typhlodromus pyriandAmblyseius potentillae, has been developed.
Instruments of the warning service for plant protection in Bayern (Germany)*
Authors: Tischner H.
Published: April 2008

The warning service for plant protection in Bayern (Germany) obtains its information mainly from its own observations. The appearance of pests (including diseases and weeds) is investigated in cultivated areas and field trials. Weather data complementary to the pest enquiries can be made available from a measuring network of 116 field weather stations and is used to estimate the development of pests in relation to weather requirements. For several fungi and animal pests, computer‐based decision support systems (DSSs) and forecasting models are being used. The results are processed and passed on to farmers via circulars, branch reviews, public notices, telephonic announcement services, telefax services and the Internet.
Development of a simulation model for the population dynamics of the onion fly Delia antiqua in Germany*
Authors: Otto M. , Hommes M.
Published: April 2008

Delia antiqua is a serious pest of many species of the genus Allium, including onions and chives. Over a period of two years (1997/1999), we have developed a model to simulate the population dynamics of D. antiqua based on an extended Leslie model. The model structure as well as the developmental functions for the different life stages of D. antiqua are presented. Using daily mean air and soil temperatures, the model calculates the population matrix for developmental stages of D. antiqua including eggs, larvae, pupae and adults. The simulation can be used to optimize the timing of control measurements against a specific life stage of D. antiqua. Flight activity can be simulated using wind speed as additional information. Simulated flight activity and the observed flight activity of D. antiqua monitored with water pan traps in three different regions of Germany in 1998 are presented and discussed. The model, which was programmed as part of the SWAT 3.5 package of programs to simulate the population dynamics of root‐fly pests in horticultural crops, will also be available via other expert systems such as PASO.
STREP: a brown‐spot disease predictor for scheduling fungicide sprays against Stemphylium vesicarium on pear*
Authors: Llorente I. , Moragrega C. , Vilardell P. , Montesinos E.
Published: April 2008

Brown spot of pear (Pyrus communis) caused by Stemphylium vesicarium is an important disease in fruit‐growing areas of Europe. The control of brown spot is based on protectant sprays of fungicide applied, at 7‐ to 15‐day intervals depending on the type of fungicide, from fruit set to preharvest regardless of the risk of infection. A forecasting model has been developed and can be used for timing the fungicide applications and to eliminate unnecessary sprays. The model quantifies the relationship between wetness duration and temperature in disease severity and can be used as a tool for the prediction of disease infection periods. The capacity of risk prediction was validated over 2 years. The fungicide sprays scheduled by the STREP forecaster were evaluated in commercial orchards during 3 years in different climatic areas in Spain and Italy. The results showed consistently that use of the STREP model minimized the number of fungicide sprays compared with a protectant schedule, but without decreasing the quality of commercial disease control. The susceptibility of selected European pear cultivars to infection by S. vesicarium and the influence of fruit age were also determined. The implementation of the model in warning stations will require the combination of predictions by the STREP model, the level of inoculum and the sensitivity of phenological stage and pear cultivar.
Control of Fusarium oxysporum f. sp. cucumerinum of cucumbers by soil solarization with impermeable plastics and/or reduced doses of methyl bromide*
Authors: Antoniou P. P. , Tjamos E. C.
Published: April 2008

Soil solarization is not broadly adopted as a soil deinfestation method mainly because of its long duration (4–6 weeks). We present evidence showing that the duration of solarization can be reduced to nearly half using impermeable plastics and/or low doses of methyl bromide, while still ensuring effective control of Fusarium oxysporum f. sp. cucumerinum. Chlamydospores of a pathogenic isolate of F. o. cucumerinum, formed in sterile soil, were inserted into nylon mesh envelopes and incorporated into the soil prior to treatment at 20‐ and 30‐cm soil depths. Soil treatments included untreated control, soil solarization with polyethylene or impermeable plastics (LMG), and soil solarization with polyethylene or impermeable plastics plus 20 g m−2 methyl bromide. According to the effects on artificial inocula of F. o. cucumerinum checked at weekly intervals for 4 weeks, soil solarization with impermeable plastics was most effective in destroying pathogen populations even two weeks after soil covering.
Fusarium solani f. sp. cucurbitae race 1, a potential pathogen of grafted watermelon production in Spain*
Authors: Armengol J. , José C. M. , Moya M. J. , Sales R. , Vicent A. , García‐Jiménez J.
Published: April 2008

A crown, root and fruit rot of squash (Cucurbita maxima and Cucurbita moschata) has been observed in eastern provinces of Spain over the past 4 years. Isolations from the crown of symptomatic plants and fruits yielded primarily a Fusarium solani that was identified as F. solani f. sp. cucurbitae race 1 on the basis of pathogenicity tests and disease symptoms in the field. In Spain, more than 90% of watermelon plants are grafted, using different Cucurbita hybrids (C. maxima × C. moschata) as rootstocks. In 1998, some grafted watermelon plants were first found to be affected by F. s. cucurbitae race 1. The purpose of this study was to evaluate the pathogenicity of this fungus on several rootstocks commonly used for grafting watermelon (Brava, Titan, Shintoza, RS‐841, TZ‐148 and TW‐1) in order to prevent a possible spread of this fungus that could cause serious economic losses in watermelon production. None of them proved to be resistant.
Influence of soil and cultural variables on fusarium wilt of melon*
Authors: Languasco L. , Giosuè S. , Rossi V. , Gualazzi M.
Published: April 2008

An investigation was carried out into the influence of certain agronomic practices (crop rotation, deinfestation of the soil and use of resistent rootstocks) and of the texture of the soil on populations of Fusarium oxysporum f. sp. melonis found in melon fields situated in the provinces of Cremona and Mantova (northern Italy). To show the associations between the variables taken into consideration, a multiple correspondence analysis was performed. The study confirmed the role played by sandy soil in increasing inoculum density and indicated that only two consecutive years of melon cultivation reach the same result. However, use of resistant rootstocks allows melon to be grown in monoculture without an excessive rise in the level of the pathogen population.
Influence of verticillium and fusarium wilts on the growth of melon
Authors: Bletsos F. A. , Thanassoulopoulos C. C.
Published: April 2008

The susceptibility of the Greek melon cvs Kokkini Banana, Thraki, Peplos and Amynteou to Verticillium dahliae and Fusarium oxysporum f. sp. melonis was tested, by inoculating seedlings of the four cultivars by root immersion in a Verticillium and Fusarium inoculum suspension for 1 h. After 35 days, disease incidence was estimated from a disease index calculated as the product of the‘leaf symptom index’and‘vascular discoloration index’of each plant. In addition, plant height, main stem diameter, above‐ground fresh and dry weight and root fresh and dry weight were measured. The disease severity of verticillium and fusarium wilts on plants was estimated by the correlation coefficient (r) between the disease index and the other characteristics. Both fungi had a significant negative effect on all the measured characteristics independently of the tested cultivar. Finally, the four melon cultivars showed different degrees of susceptibility to Verticillium and Fusarium indicating that tolerant selections can be achieved.
Assessment of vegetative compatibility of Acremonium cucurbitacearum and Plectosphaerella cucumerina isolates from diseased melon plants*
Authors: Abad P. , Pérez A. , Marqués M. C. , Vicente M. J. , Bruton B. D. , García‐Jiménez J.
Published: April 2008

One of the most important disease complexes of melon in Spain has been referred to as collapse, sudden wilt or vine decline. Acremonium cucurbitaceaum and Plectosphaerella cucumerina (anamorph Plectosporium tabacinum) are two of the fungi implicated in this disease complex. Genetic diversity among populations of these two plant pathogens has been approached by the assessment of vegetative compatibility using nitrate non‐utilizing auxotrophs. In A. cucurbitacearum, with a host range limited to Cucurbitaceae and found in Spain and USA (California and Texas), 10 vegetative compatibility groups have been identified. Plectosphaerella cucumerina has worldwide distribution and wide plant‐host range. From a collection of P. cucumerina isolates with different plant and geographical origins, only four pairs have developed complementary heterokaryons when pairings of phenotypically distinct nit mutants (nit× NitM) were conducted. Each of the four vegetative compatibility groups consists of two members with close geographical origin and all the isolates were from diseased melon plants. Of the remaining P. cucumerina isolates, two did not produce nit mutants, two were self‐incompatible and the others were vegetatively incompatible among themselves, suggesting that this fungal species may have wide genetic diversity in nature.
Natural compounds in the control of powdery mildew on Cucurbitaceae*
Authors: Casulli F. , Santomauro A. , Faretra F.
Published: April 2008

Powdery mildew, caused by Sphaerotheca fuliginea, is a major disease of Cucurbitaceae. The use of natural compounds as alternatives or complements to chemical fungicides would be helpful because the crops require continued prolonged harvesting, during which young unsprayed leaf tissues continuously become available for infection. Several natural compounds were tested on courgette and cucumber plants grown under glasshouse conditions and artificially inoculated with S. fuliginea. Both sodium bicarbonate (0.5%) and mineral oil (1%) proved to be effective in keeping infections under control. These compounds showed a remarkable effectiveness when used in combination. The best results were achieved when the plants were treated after infection but before the disease appeared. Other compounds tested, such as sodium silicate and azadiractin, showed some effectiveness, but satisfactory control of the disease was achieved only at doses causing phytotoxicity in the form of necrotic spots on the leaves, especially on cucumber.
Isolement et identification morphologique et moléculaire des espèces de Fusarium transmises par les semences de pastèque
Authors: Gargouri S. , Hajlaoui M. R. , Abdennadher M. , Marrakchi M.
Published: April 2008

L'analyse fongique des semences de pastèque a révélé leur contamination par différentes espèces de Fusarium. En se basant sur des critères morphologiques et des analyses de I'ADNr, quatre espèces de Fusarium ont été identifiées. II s'agit de F. oxysporum, F. solani, F. moniliforme et F. equiseti. L'amplification de I'ADN ribosomique par deux amorces universelles suivie de digestion enzymatique a permis de distinguer entre les différentes espèces de Fusarium isolées à partir des semences de pastèque. La pathogénicité des isolats de chaque espèce de Fusarium a été testée sur des plants de pastèque sensibles (cv. Sugar Baby). Sur la base de ces tests d'inoculation, les isolats pathogènes de F. oxysporum et F. solani ont été séparés des non pathogènes. Tous les isolats de F. moniliforme et F. equiseti testés se sont révélées non pathogènes sur pastèque.
Fusarium wilt of watermelon in Cyprus and its management with soil solarization combined with fumigation or ammonium fertilizers
Authors: Ioannou N. , Poullis C. A. , Heale J. B.
Published: April 2008

Fusarium wilt is a limiting factor to watermelon production in Cyprus. In previous studies, soil solarization applied in 1‐m‐wide strips provided only partial disease control. In order to improve the effectiveness of solarization, three field experiments were carried out in heavily infested soils, using various solarization techniques, alone or in combination with methyl bromide fumigation or soil amendments with ammonium‐based fertilizers. Increasing the width of the solarization strip from 1 to 2 m had no significant influence on its effectiveness. Solarization with a double rather than single polyethylene sheet, in either 1‐ or 2‐m‐wide strips, improved slightly the level of wilt control but had no significant effect on yield. Combined solarization–methyl bromide treatments, however, improved significantly the level of wilt control and increased marketable yield by up to 100% over that obtained with either method alone. The low rate of methyl bromide (50gm−2) was as effective as the normal rate used by growers (100 g m−). Soil amendment with ammonium‐based fertilizers improved even more the effectiveness of solarization and increased yield by up to 200% over that obtained with solarization alone. Best results were obtained with ammonium sulphate or monoammonium phosphate at a rate equivalent to 180 kg N ha−1.
Mise en évidence de l'effet antagoniste de Pseudomonas fluorescens vis‐à‐vis de la fusariose vasculaire de la tomate
Authors: Benchabane M. , Bakour R. , Toua D. , Boutekrabt A.
Published: April 2008

Les rhizobactéries du groupe Pseudomonas fluorescens sont considérées parmi les microorganismes à effets bénéfiques sur le biocontrôle et la biostimulation de la croissance des plantes cultivées. La caractérisation de quelques souches, isolées en Algérie, a révélé des potentialités d'antagonisme appréciables in vitro vis‐à‐vis de Fusarium oxysporum f. sp. lycopersici. La bactérisation des semences et des plantules de tomate a induit l'inhibition, voire même l'annulation de l'expression des symptômes de la fusariose.
Bacterial spot of capsicum and tomato in Yugoslavia
Authors: Obradović A. , Mavridis A. , Rudolph K. , Arsenijević M.
Published: April 2008

The causal agent of bacterial spot of capsicum and tomato grown in different regions in Yugoslavia was investigated. Isolations were made from diseased material collected in recent years. The biochemical and physiological characteristics of isolated bacteria were studied by standard bacteriological tests. The race of the pathogen was determined on differential cultivars of capsicum and tomato. The causal agent of the disease was identified according to the concepts of the time as Xanthomonas campestris pv. vesicatoria. Strains isolated from diseased capsicum were non‐pectolytic and non‐amylolytic, and did not infect tomato plants. According to the reaction of capsicum cv. Early Calwonder and its isogenic lines, these strains belonged to‘pepper races’1 and 3 of X. vesicatoria. Tomato strains showed pectolytic and amylolytic activity and were not pathogenic to capsicum. Accordingly, the capsicum strains could now be considered to be X. axonopodis pv. vesicatoria and the tomato strains X. vesicatoria.
Pathogenesis and control of bacterial speck, Pseudomonas syringae pv. tomato, on tomato*
Authors: Saad A.T. , Hassan H.M. Abul
Published: April 2008

Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, was observed to cause severe symptoms, especially on protected tomato crops, during the winter season in the coastal area of Lebanon. This study was conducted to investigate the aetiology and pathogenesis of the bacterium involved and the efficacy of different chemicals for the control of the disease. Biochemical, physiological and pathological tests verified the identity of the bacterium involved as P. s. tomato. Periodic histological sectioning of inoculated tomato leaves showed that bacterial cells resided and multiplied in depressions and around trichome bases for 24 h before penetration through stomata and trichome basal cells. The bacteria invaded intercellular spaces and caused cell lignification, collapse and shrinkage, 48 h after inoculation. Necrotic lesions filled with bacterial masses and collapsed lignified cells were readily observable at and after 72 h. No detectable histological changes were observed in the yellow halo region surrounding the necrotic leaf specks. A thermostable toxin was produced by the pathogen and is involved in chlorotic symptom expression. An antibiotic mixture of streptomycin + oxytetracy‐cline was most effective in controlling infections followed by copper oxychloride + mancozeb, tribasic copper sulphate + sulphur, copper oxychloride and copper oxychloride + zineb.
Diagnostics and National Plant Protection Organizations*
Authors: van Halteren P.
Published: April 2008

Under the growing influence of trade globalization and consumer‐driven politics, National Plant Protection Organizations (NPPOs) require information on quarantine pests that is more precise and science based. In order to operate rapidly and effectively, they need to employ diagnosticians as an integral part of their structure.
Detection of Ralstonia solanacearum from potato tissue by post‐enrichment TaqMan PCR*
Authors: Weller S. A. , Elphinstone J. G. , Smith N. C. , Stead D. E.
Published: April 2008

TaqMan polymerase chain reaction (PCR) exploits the 5′‐nuclease activity of Taq DNA polymerase in conjunction with fluorogenic DNA probes. A positive PCR reaction results in a measurable emission of fluorescence within 2 h. TaqMan assays for several plant‐pathogenic bacteria have been designed, including the potato brown rot pathogen Ralstonia solanacearum. Enrichment techniques designed to improve the detection of low pathogen populations in potato tissue are also suitable for use with TaqMan PCR. The quantitative aspect of TaqMan PCR enables relative population level differences between pre‐enriched and enriched samples to be demonstrated and thus cell viability to be evaluated.
Evaluation of magnetic capture for the detection of Ralstonia solanacearum in various substrates*
Authors: Expert J. M. , Noublanche F. , Poliakoff F. , Caffier D.
Published: April 2008

Ralstonia solanacearum, the causal agent of bacterial wilt, is an important quarantine pest for European countries. Available analytical tools give good results for the detection of the bacterium in potato tuber extracts and tomato macerates. The pathogen may be present in complex substrates such as environmental water, soils, sewage sludge and potato processing wastes, which therefore have to be tested. Immuno‐magnetic separation and DNA magnetic capture combined with other tests have been investigated for this purpose and appear promising.
Blackleg risk potential of seed potatoes determined by quantification of tuber contamination by the causal agent and Erwinia carotovora subsp. atroseptica: a critical review*
Authors: Pérombelon M. C. M.
Published: April 2008

Blackleg is a seed‐borne disease of potato caused by the soft rot bacterium Erwinia carotovora subsp. atroseptica in temperate regions. Although most seed stocks are extensively contaminated, blackleg incidence is related to seed contamination level, the threshold level for disease development being about 103 cells of E. c. atroseptica per tuber. Disease control relies primarily on the production and use of‘clean’seed potatoes. This is better achieved by planting seed potatoes with a low contamination level than by certification based on blackleg inspection and rogueing. Testing seed‐potato stocks for E. c. atroseptica involves four steps, which have not all been fully evaluated. First, sampling to reflect variation in tuber contamination level. Second, tuber tissue is prepared for testing. Third, determination of numbers of E. c. atroseptica, which can be carried out using a selective diagnostic medium (CVP), immunofluorescence colony staining after immuno‐capture of the target bacteria, enzyme‐linked immunosorbent assay (ELISA) applied to tuber extract after enrichment and a quantitative polymerase chain reaction (PCR) assay. Although all methods have the necessary sensitivity level, they suffer from certain important drawbacks, including reliability, specificity and ease of use. Last, interpretation of contamination results in terms of blackleg risk assessment. These steps are discussed critically as a basis for future studies.
On‐site detection of plant pathogens using lateral‐flow devices*
Authors: Danks C. , Barker I.
Published: April 2008

One‐step lateral‐flow tests have been developed for the on‐site detection and identification of several plant viruses. They utilize specific monoclonal and polyclonal antibodies in an immunochromatographic format, incorporating antibody‐coated latex particles. These tests have been combined with a novel extraction procedure to allow disease diagnosis in the field within 3 min. Lateral‐flow devices for two potato viruses (Potato Y potyvirus and Potato X potexvirus) have been demonstrated as being 100% accurate in preliminary trials, when compared with traditional microplate enzyme‐linked immunosorbent assays. This paper reviews the techniques currently employed for on‐site detection of plant pathogens. The development of lateral‐flow devices is described and their possible impact on plant disease diagnosis is discussed.