bluuebunny/crossref_metadata_2025 huggingface dataset:
Tomato yellow leaf curl geminivirus: serological evaluation of an improved purification method 1
Authors: AL‐BITAR L. , LUISONI E.
Published: April 2008

Tomato yellow leaf curl geminivirus is an important limiting factor for tomato production and is now expanding into new areas. Difficulties in virus purification and low antigenicity of virus particles have so far allowed the production only of low‐titre antisera. To obtain better antisera, the purification method has to be improved, and this in turn requires better methods for measuring the yields of virus obtained using alternative purification procedures. For this purpose, we have investigated four types of ELISA test. Among these, biotin‐avidin ELISA gave good results under all conditions; indirect ELISA gave better results with concentrated virus preparations but did not work with crude extracts. Two DAS‐ELISA types, differing in conjugation procedures, gave less reliable results. On the bases of these tests, the best purification method proposed included a 24‐h incubation of the homogenate at 37°C with Driselase (macerating enzymes), and gave a 4–8 fold increase in yield, compared with the best method previously used. Nicotiana benthamiana was confirmed to be the best source plant.
Detection of plant viruses by PCR using group or virus specific primers (potyviruses, bymoviruses) 1
Authors: COLINET D. , KUMMERT J. , DUTERME O. , LEPOIVRE P.
Published: April 2008

A combined assay of reverse transcription and the polymerase chain reaction (RT‐PCR) utilizing degenerate primers derived from conserved regions in the genome of potyviruses was designed in order to amplify the 5’terminal part of the coat protein cistron, which can differ greatly in length between distinct potyviruses. Amplification on total RNA extracted from one sweet potato clone from China yielded three fragments of different lengths, and sequence analysis of these fragments indicated mixed infections by three distinct potyviruses in the sweet potato clone investigated. Two degenerate primers were also designed in order to amplify the 5’terminal part of the coat protein cistron of either potyviruses or bymoviruses. A third degenerate primer was selected from a region conserved in potyviruses and bymoviruses and used with primers specific for two different bymoviruses, barley yellow mosaic bymovirus (BaYMV) and barley mild mottle bymovirus (BaMMV). These primers allowed the identification of BaYMV and BaMMV barley plants from the field with single or mixed infection, and were used to clarify the etiology of a viral agent inducing mosaic symptoms on several barley cultivars considered so far as resistant to BaYMV and BaMMV. Amplification of fragments, including the variable 5’terminal region of the coat protein cistron, thus provides a convenient method for the detection and characterization of potyviruses and bymoviruses, without fastidious preliminary work of separation and purification of the components of viral complexes.
Use of PCR in the detection and characterization of geminiviruses 1
Authors: BRIDDON R. W. , MARKHAM P. G.
Published: April 2008

Three methods utilizing PCR technology for the detection of members of the Geminiviridae are described. As well as being a tool useful for detection, the products of the diagnostic PCR reactions are suitable for further characterization of the viruses. Firstly, a pair of degenerate primers has been used to allow the detection of geminiviruses infecting dicotyledonous plants by PCR amplification. Secondly, a set of specific primers has been used which discriminate between the economically significant maize streak geminivirus and closely related viruses which infect mainly grasses. Finally, a PCR‐based method for the production of full‐length, infectious geminivirus clones is described. The advantages and disadvantages of PCR compared with other methods of detection and characterization are discussed.
A procedure for identification of polyphagous Liriomyza species using enzyme electrophoresis 1
Authors: OUDMAN L. , AUKEMA B. , MENKEN S. B. J. , ULENBERG S. A.
Published: April 2008

Liriomyza bryoniae, L. strigata, L. huidobrensis, L. trifolii and L. sativae are leafminers of great economic importance. Morphological identification is difficult and only possible in some life stages. Cellulose‐acetate gel electrophoresis provides a method for identification of all five species in each stage of the life cycle. The present paper describes the procedure for electrophoresis. The patterns of genetic variation of diagnostic enzymes and a biochemical key are presented. In addition, the electrophoretic patterns of the three most common parasitoids of Liriomyza are given.
Fusarium spp. as a cause of crown and root rot of asparagus in Greece
Authors: ELENA K. , KRANIAS L.
Published: April 2008

Specimens of diseased asparagus (108) were selected from 17 fields in northern Greece. The asparagus crowns showed limited or widespread brown discoloration or extensive internal rot with fibrous tissues. A red‐brown discoloration was also observed on the roots and, in a serious infection, most of the roots were totally destroyed and only their epidermis and ribbon‐like central axis remained. 68 strains of Fusarium proliferatum, 25 of F. oxysporum, 19 of F. solani, and 1 strain of Rhizoctonia solani were isolated from crowns and roots. Single‐spore isolates were subcultured from 50 strains of F. proliferatum, 21 of F. oxysporum and 7 of F. solani. These isolates were evaluated for pathogenicity by inoculating cultivar UC157F1 of asparagus in an in vitro agar test‐tube assay for 21 days at 29–32°C, with a light period of 16 h. Isolates of F. proliferatum and F. oxysporum were found to be the most pathogenic. The pathogenic F. oxysporum isolates were characterized as f.sp. asparagi.
The diagnostic value of the cement gland and other abdominal structures in aleyrodid taxonomy
Authors: GUIMARÃES J. M.
Published: April 2008

The morphological characters on which the taxonomy of the Aleyrodidae is based are found in the last instar larvae (pupae). Since in many situations only adults are available (as in sticky trap catches), difficulties may arise if specific determination is needed. In fact, the information given by the vasiform structure of adults and the male genitalia is not always conclusive. In the course of the present study, two sources of useful information were found in the female abdomen, namely the morphology of the cement gland and the setal pattern of the gonapophyses. Both structures can easily be examined by light microscopy, with a simple method of preparation. These characters (mainly those concerning the cement gland) have been consistent enough to allow identification of the main whitefly pest species in Portugal. An identification key mostly based on these structures is presented for Aleurothrixus floccosus, Aleyrodes proletella, Bemisia tabaci, Parabemisia myricae, Siphoninus phillyreae, Trialeurodes vaporariorum and Dialeurodes citri (this last not yet found in Portugal).
16S rDNA‐derived oligonucleotide probes for the differential diagnosis of plum leptonecrosis and apple proliferation phytoplasmas
Authors: MALISANO G. , FIRRAO G. , LOCCI R.
Published: April 2008

The 16S rRNA gene of plum leptonecrosis phytoplasma has been PCR‐amplified, cloned and almost completely sequenced (1201 bp). The sequence analysis confirmed the close genetic relationship between plum leptonecrosis phytoplasma and the phytoplasmas associated with other stone‐fruit diseases in Europe. By comparison with the 16S rDNA sequence of apple proliferation phytoplasma, two oligonucleotides were selected, differing by two nucleotides, which were specific for apple proliferation and plum leptonecrosis phytoplasmas, respectively. The oligonucleotides were labelled with digoxigenin and hybridized, in the presence of tetramethylammonium chloride, to 16S rDNA fragments amplified from apple and plum leaf samples. The results showed that, under the described hybridization conditions, the two phytoplasmas could clearly be distinguished. The advantage of the proposed technique over 16S rDNA restriction fragment length polymorphism is discussed.
The epidemic models for Phytophthora infestans and Pseudocercosporella herpotrichoides and their regional adaptation in Germany 1
Authors: GUTSCHE V. , KLUGE E.
Published: April 2008

The computer‐aided models SIMPHYT I and II simulate the start and further progress of epidemics of Phytophthora infestans depending on weather, initial infection pressure, resistance of cultivars and application of fungicides. The model SIMCERC simulates epidemic progress (infected plants and growth of mycelium through the leaf sheaths) of Pseudocercosporella herpotrichoides on winter wheat and winter barley depending on weather factors. To use the models for prognostic purposes, an adaptation to regional conditions was necessary. For this adaptation, specific model parameters (regional factors) were defined. Their quantitative values were related to the region and a first data set was obtained by simulation experiments. The relation of these parameters to regional climatic factors was investigated and described by regression functions. Appropriate regional factors were calculated on this basis for each meteorological station used in the project. The regional factors may be interpreted as a characteristic of the different‘infection pressure’in the regions of Germany.
Simulation of the disease incidence of Puccinia dispersa in rye 1
Authors: SELHORST T. , HINDORF H.
Published: April 2008

A model has been developed to forecast the disease development of brown rust of rye (Puccinia dispersa), describing the time (t), temperature (T) and relative humidity (RH) dependence of disease intensity D(t,T, RH) and giving the logistic function D(t, T,RH) = D0K/{D0–(D0–K)exp[–r(T,RH)t]}. The influence of temperature and relative humidity on parameter r (intrinsic growth rate) has been modelled using secondary functions. The parameters of these secondary functions have been estimated using experimental data ascertained in the glasshouse as well as in the field. By using the secondary functions, disease progress can be forecasted if actual temperatures and relative humidities are known.
Modelling the development of juvenile individuals of Panonychus ulmi1
Authors: SELHORST T.
Published: April 2008

An attempt has been made to estimate the parameters of a model describing the development process of individuals of Panonychus ulmi at the larval, protochrysalis, protonymph, deutochrysalis, deutonymph and teleiochrysalis stages, using field data on their abundance. To perform the parameter estimation, a population simulation model was linked with an algorithm to perform the parameter estimation. The proposed method for parameter estimation gave excellent results, and so seems to provide a practical means for the development of simulation programs for insect population dynamics.
Establishing a plant protection advisory service in Austrian vineyards and apple orchards, based on electronic climate stations 1
Authors: DENZER H.
Published: April 2008

In 1995, P.B. Consult established a plant protection advisory service in horticulture and viticulture in Austria. Each client has his own weather station or shares a weather station with another grower nearby. Field monitoring is done using forms and instructions from P.B. Consult, either by staff or by interested growers. For disease forecasts, weather data is collected by telephone on a central computer at 0500 every day. Infection conditions and potential inoculum for weather‐driven diseases like Venturia inaequalis and Plasmopara viticola are evaluated by computer. For Uncinula necator, initial infection can be forecast from field observations indicating the presence of flag shoots (carrying overwintered mildew) or from weather conditions favouring ascospore discharge and germination, then further propagation can be predicted on the basis of temperature. There are no simulation models leading to direct advice for insect pests in horticulture and viticulture but, in some cases (Hoplocampa testudinea, Cydia pomonella), cumulative temperatures and temperature thresholds are good tools for reducing the number of field observations and for fixing the date of field observations.
A new agrometeorological advisory system for environmentally friendly viticulture in Germany 1
Authors: HOPPMANN D. , HOLST H.
Published: April 2008

Some 3000 ha are covered by vineyards in the wine‐producing area of Rheingau (Hessen, DE). By cooperation between the Forschungsanstalt Geisenheim (Research Station for Viticulture), the advisory station for viticulture and the Agrometeorological Advisory and Research Station of the German Weather Service, a new system has been established to send a fax to wine‐growers twice a week, containing both weather and agrometeorological information and remarks on plant protection, fertilization and soil cultivation. The data base consists of three columns: (1) data from different weather stations, (2) data from weather forecasts and (3) estimations and soil analyses made in plant stands. The following electronically supported procedures can be offered to the user at present: (1) risk forecast for Plasmopara viticola; (2) forecast of flight date for Eupoecilia ambiguella and Lobesia botrana; (3) advice on nitrogen fertilization; (4) evaporation of plant protection treatments; (5) calculation of soil moisture for the management of soil cultivation in grassed‐over or normally ploughed vineyards. The new advisory system leads to decreased expenditure on plant protection products and soil‐applied fertilizers.
Developing a European pest risk mapping system1
Authors: BAKER R. H. A.
Published: April 2008

Following the 1993 World Trade Organization (WTO) agreement, pest risk analyses (PRAs) must now follow internationally agreed standards. However, the international PRA standards under development provide little detailed guidance on the most complex areas of PRA: the assessment of introduction potential and economic impact. This is particularly difficult when a large area, such as Europe, with a wide variety of climatic zones and crop agroecosystems is being studied. This paper shows that the datasets required to analyse the potential for pest establishment can best be integrated and the results displayed in a pest risk map using a Geographical Information System (GIS). To illustrate how a pest risk mapping system might be developed, European risk maps forLeptinotarsa decemlineata, Ceratitis capitataandBactrocera tryoniwere constructed using CLIMEX, a dynamic simulation model which predicts potential distribution based on climate, with a 0.5° latitude × 0.5° longitude 1961–90 European gridded climatology and displayed in a GIS. The developments required to refine these predictions and create a generic European pest risk mapping system are outlined.
Possible consequences of an internationally agreed pest risk assessment scheme (PRA) 12
Authors: VAN HALTEREN P.
Published: April 2008

The EPPO Panel on Pest Risk Analysis should have an internationally agreed Pest Risk Assessment Scheme developed by the end of 1996, within the framework of the FAO standard for pest risk analysis. Such a scheme has consequences for the status of the EU and EPPO lists of quarantine pests, for the attitude and working habits of the countries in Europe and of the European Commission, for developing and other non‐EU countries, and for the activities of plant protection services. A bird's eye view of these possible consequences is given.
ONIMIL, a forecaster for primary infection of downy mildew of onion 1
Authors: BATTILANI P. , ROSSI V. , RACCA P. , GIOSUÈ S.
Published: April 2008

Onion downy mildew, caused by Peronospora destructor, can be controlled effectively only when sprays are begun in the infection period following first sporulation. Systems analysis was applied to the onion/P. destructor pathosystem in order to understand better the relationships between the factors influencing the establishment of primary infection. A preliminary model able to forecast primary infection, ONIMIL (ONIon downy MILdew), was developed. This model was able to determine, for each day, the probability of P. destructor establishing an infection on onion and its infectivity level, compared with the maximum. The model uses empirical rules and mathematical functions based on meteorological factors.
Forecasting models and warning services in Emilia‐Romagna (Italy) 1
Authors: BUGIANI R. , TISO R. , BUTTURINI A. , GOVONI P. , PONTI I.
Published: April 2008

The Integrated Production project in Emilia‐Romagna involves 152 technicians and covers 7300 farms over more than 50 000 ha. The use of forecasting models is an important part of the pest control strategy, so a warning service using forecasting models integrated with biological data from field surveys is fundamental in further improving the potential of the project, and maintaining high quality. The Integrated Warning Service requires: a computing system, a network of weather stations, field monitoring systems (spore traps and pheromone traps) and an efficient extension service able to perform local field surveys and to give advice to farmers. At the moment, the Regional Information System uses forecasting models for Venturia inaequalis, Plasmopara viticola, Phytophthora infestons on tomato, Cydia pomonella, Lobesia botrana, and apple leafrollers (Pandemis cerasana and Argyrotaenia pulchellana). In future, other forecasting models will be introduced into the Regional Information System. The Warning Service is based on the integration of information provided by the forecasting models with that from field monitoring, so as to give more precise warnings about the real risk of pest outbreaks along with the best control strategy. Warnings are sent out by means of weekly bulletins, television programmes and telephone answering machines.
Development of a cost/benefit model for phytosanitary eradication campaigns 1
Authors: ROOSJEN M. G. , BOUWMAN V. C. , BARWEGEN J.
Published: April 2008

Because of the great impact of most phytosanitary eradication campaigns, there is a need for reproducible quantified analyses of costs and benefits of these campaigns. The Plant Protection Service (PD) together with the Agricultural Economics Research Institute (LEI‐DLO) is in the process of developing a simplified cost/benefit model.
Experiences in the introduction of computer aids for decision making in the Plant Protection Service of Baden‐Württemberg 1
Authors: DÖLZ A.
Published: April 2008

This article describes the introduction of computer aids for decision making by the plant protection service of Baden‐Württemberg (DE) and the experience obtained. In order to supply current weather data, it was necessary to install a logger network. Operating the programs by themselves, the advisers have direct access to the weather data. Experience shows that the tested computer aids for decision making can be used routinely after consistent automation of program routines. They should be a real help for the adviser, so all programming possibilities have to be used to minimize efforts connected with interactive operation of the programs. Without running the programs as batch files, evaluations for several stations in the region are hardly reasonable for the adviser. In order to get the required acceptance in the Plant Protection Service, some of the programs being tested at the moment need to be revised.
Sensitivity of different methods for the detection of Ralstonia solanacearum in potato tuber extracts
Authors: ELPHINSTONE J. G. , HENNESSY J. , WILSON J. K. , STEAD D. E.
Published: April 2008

The sensitivities of various methods for the detection of Ralstonia solanacearum following dilution in healthy potato tuber tissue macerate were compared. Estimated pathogen populations in undiluted macerates, from samples of 200 heel‐end vascular cores each containing a single diseased and 199 healthy tubers, ranged from 1.2 × 106–7.4 × 107 colony‐forming units per ml. Following concentration by high‐speed centrifugation and resuspension in phosphate buffer, the pathogen was detected by all methods studied, including culture on semi‐selective media, enzyme‐linked immunosorbent assay (ELISA), indirect immunofluorescent‐antibody staining (IFAS) of fixed cells, immunofluorescent colony staining (IFCS), detection of specific DNA sequences following amplification by the polymerase chain reaction (PCR) and bioassay in tomato seedlings. Both ELISA and PCR methods were improved by pre‐enrichment of samples in semi‐selective broth prior to testing. A nested PCR method was evaluated which could detect fewer than 10 cells per ml in the potato extracts. Of the other methods only dilution plating on semi‐selective medium and tomato bioassay could detect fewer than 104 cells per ml. In order to combine ease and speed of use with sensitive detection, it was recommended that a series of methods be used for routine screening of potato tuber stocks for infection by R. solanacearum.
Potato brown rot in western Europe – history, present occurrence and some remarks on possible origin, epidemiology and control strategies
Authors: JANSE J. D.
Published: April 2008

Since 1992 an increased number of outbreaks of potato brown rot, caused by the bacterium Ralstonia (Burkholderia, Pseudomonas) solanacearum race 3, biovar 2, has been reported in several EPPO member countries, including more northern states like Belgium, France, The Netherlands and the UK. The largest outbreak took place in The Netherlands in 1995, mainly through one heavily infected seed‐tuber line. The bacterium was found in most infested countries in surface water and in the weed Solanum dulcamara growing along waterways. In some countries, tomato was also found to be infected. The history of the so‐called‘low‐temperature’race 3, adapted to more temperate climates (also occurring at higher altitudes in the tropics) is described, together with details on its host range and geographical distribution. Possible origins of the disease in western Europe are discussed, including introduction through import of infected early ware or industrial potatoes from some countries in the Mediterranean area, where the disease is established. The brown rot bacterium has many similarities concerning its biology and epidemiology with some other infectious diseases, e.g. with cholera, and useful comparisons can be made for control strategies. A detailed account on the epidemiology of P. solanacearum and possible prevention and control strategies is presented. These strategies are: (1) responsibility for prevention and control is for the country where the disease occurs; (2) countries where the disease occurs should report outbreaks as soon as possible; (3) early and sure detection and diagnosis of the pathogen are the core of the system; (4) adequate prevention and control measures should be taken after an outbreak; (5) production of healthy seed tubers should be guaranteed and surveys and (laboratory) checks for (latent) infections performed; (6) education of scientific personnel and the public (farmers, traders, advisory service, etc.) is essential. It is foreseen that hygienic measures and avoidance of surface water for irrigation will be key factors in successful control of the disease.
Résistance de Botrytis cinerea aux benzimidazoles et aux dicarboximides dans les cultures abritées de tomate en Tunisie
Authors: HMOUNI A. , HAJLAOUI M.R. , MLAIKI A.
Published: April 2008

Suite à des prospections effectuées en 1995 sur des cultures de tomate abritées, la pourriture grise s'est avérée la maladie la plus grave malgré une intense protection phytosanitaire. L'étude au laboratoire de la sensibilité de quelques isolats de Botrytis cinerea aux principaux fongicides antibotrytis employés en Tunisie a montré la forte résistance du parasite au bénomyl. En effet, les isolats testés se sont développés sur milieu de culture enrichi de 100 ppm de cette matière active. A cette même concentration, l'inhibition de la croissance mycélienne a été inférieure à 62,8% et les fréquences des spores résistantes ont été supérieures à 86,8%. Pour certains isolats, la CI 50 a dépassé 100 ppm. D'autre part, tous les isolats testés se sont développés en présence d'iprodione ou de chlozolinate et peuvent être considérés comme résistants à ces deux produits. A 10 ppm de matière active, ces dicarboximides ont inhibé la croissance mycélienne de 61,4–80,5%. A cette concentration, la résistance des spores au chlozolinate a atteint une fréquence de 91%. L'apparition de la résistance à ce fongicide, non encore homologué en Tunisie, pourrait être liée à une résistance croisée positive avec d'autres produits de la même famille.
Pepper mild mottle tobamovirus found infecting cultivars of Capsicum annuum in Zambia
Authors: NDUNGURU J. , KAPOORIA R. G.
Published: April 2008

A virus disease of Capsicum annuum was noticed on some sweet pepper cultivars grown in Lusaka Province (ZM) during the cropping season 1995/1996. Using differential indicator plants and serological tests, the virus was identified as pepper mild mottle tobamovirus (PMMV). Farms surveyed south and east of Lusaka showed plant infections ranging between 20 and 30% and 20 and 40%, respectively. This is the first report on the occurrence of PMMV on capsicum cultivars in Zambia.
Application Techniques Division of the Biologische Bundesanstalt (Germany)1
Authors: GANZELMEIER H.
Published: April 2008

The Application Techniques Division belongs to the Department for Plant Protection Products and Application Techniques of the Biologische Bundesanstalt fur Land‐ und Forstwirtschaft (BBA). Its main task is to test plant protection equipment. for which there are in Germany two complementary procedures. As stipulated by the law since the middle of 1988, manufacturers and distributors are obliged. before plant protection equipment is put on the market for the first time, to produce an appropriate declaration. Manufacturers and distributors can also have their plant protection equipment, or parts of it, tested on a voluntary basis. The Application Techniques Division also cooperates in the procedure for approval of plant protection products and is involved in updating the regulations for good professional practice. The Application Techniques Division has very modern and efficient testing facilities and installations for plant protection equipment; it cooperates in research programmes with several European partners.
Evaluation of the quality of spray distribution from boom sprayers in practical conditions1
Authors: SINFORT C. , HERBST A.
Published: April 2008

The quality of distribution from field sprayers involves many parameters. Distribution is affected by environmental conditions. It also depends on static parameters concerning the boom at rest, and dynamic parameters involving boom movements. Field measurements at the Biologische Bundesanstalt (BBA) have shown the importance of the dynamic criteria. To avoid the effect of environmental parameters. one solution is to use a track simulator. A method has been developed at Cemagref (FR) to simulate distribution on soil from measurements of boom movements on the track simulator. Other evaluation methods have been dcvcloped by other laboratories. Two EU research programmes are now under way to develop test methods for field sprayer booms. The aim of the first is to compare the methods used to show the effect of boom movements. The second concerns the development of a test method for inspecting sprayers on firms. The results of these two projects will be used for the elaboration of an IS0 standard.
Distribution quality of orchard sprayers1
Authors: KAUL P. , SCHMIDT K. , KOCH H.
Published: April 2008

Studies of the variability of initial deposition on leaves from orchard sprayers showed that both minimum and maximum values and the coefficient of variation of the amounts deposited increased in a linear manner with the application rate. The minimum and maximum amounts of deposit are important for biological efficacy, potential development of resistance. determination of the dose rate and effects on beneficial organisms. Measurements of the amounts deposited on leaves at different tree heights showed that the reproducibility of curves is considerably interfered with by random effects. There was not always a connection between these curves and measurements on a lamellate vertical distribution test stand. Measurements of vertical distribution from a fixed position differed considerably from those produced with forward movement.
Plant protection equipment in glasshouses1
Authors: WYGODA H.‐J. , RIETZ S.
Published: April 2008

The use of pedestrian equiprnent such as sprayers, blast sprayers and fogging machines in glasshouses of dilferent size is still very common. Hand‐held sprayers or those carried by straps on the back or on one shoulder are well known. Fogging machines are in use as pedestrian or stationary equipment. For pedestrian sprayers, the quality of distribution and the accuracy ofdosing depend very much on the qualification of the operator. As to the use of stationary cold fogging, a summary is given of a research programme to investigate various influences on the quality of distribution and recovery. To guarantee reproducible results in distribution quality, the model of the cold‐fogging machine has to be adjusted to the size of the glasshouse. In big cold houses, it is important to have sufficient circulation of the airstream. The force of the circulating airstream depends on droplet size and on the size of the glasshouse. Good distribution quality and high recovery rate cannot be achieved at the same time.
Requirements for safeguarding the health of applicators of plant protection products ‐ an overview1
Authors: KIECZKA H.
Published: April 2008

For the purpose of preventive health protection, specific instructions for applicator protection are required in the directions for use of plant protection products. A risk assessment for applicators is obligatorily made before the specific instructions are selected. The principle of the German model, the steps of risk asscssinent. and the consequent derivation of specitic instructions for health protection are presented.
Phytosanitary status of almond and apricot in Tunisia
Authors: ZERAMDINI H. , DI TERLIZZI B. , SAVINO V.
Published: April 2008

Surveys were carried out in the traditional areas of almond and apricot cultivation in Tunisia to assess the phytosanitary status of these species in varietal collections, mother block stands and commercial orchards. The presence of virus and virus‐like diseases was ascertained through field surveys, sap transmission to herbaceous hosts, and ELISA and IEM tests. The mean infection level in almond was 34%. compared with only 4.7% in apricot. The following viruses were identified: apple chlorotic leaf spot trichovirus (ACLSV), apple mosaic (ApMV), prune dwarf (PDV) and prunus necrotic ringspot (PNRSV) ilarviruses. Plum pox potyvirus (PPV) was not detected. Likewise, none of the six nepoviruses tested for (SLRV, TBRV, RRV. CLRV. ArMV and ToRSV) was encountered.
Preliminary account of the phytosanitary status of stone‐fruit trees in Lebanon
Authors: JAWHAR J. , DI TERLIZZI B. , KHOURYM W. , SAVINO V.
Published: April 2008

Investigations were carried out in the main stone‐fruit growing areas of Lebanon to assess the phytosanitary condition of commercial orchards. The presence of virus and virus‐like diseases and their identification was ascertained through: (i) field surveys, (ii) sap transmission to herbaceous hosts, (iii) graft transmission to woody indicators; and (iv) ELISA and IEM tests. The mean infection level was 25%. ranging from 5% in apricot to 45% in cherry. The following viruses were identified: apple chlorotic leaf spot trichovirus (ACLSV), prunus necrotic ringspot (PNRSV) and prune dwarf (PDV) ilarviruses. Plum pox potyvirus (PPV), apple mosaic ilarvirus (ApMV), and six nepoviruses tested for (SLRV, TBRV, RRV, CLRV, ArMV and ToRSV) were not encountered.
Benefits and risks of introducing exotic macro‐biological control agents into Europe1
Authors: VAN LENTEREN J. C.
Published: April 2008

Biological control of insects — the use of natural enemies to reduce pest numbers — has been applied on a worldwide scale for more than 100 years and its use has considerably increased during the past decades as it offers a sustainable, economical and environmentally attractive alternative to chemical pest control. In biological control, locally occurring natural enemies are used or alien species are imported. Until now, introductions of hundreds of species of insect natural enemies have not led to environmental problems when a procedure of selection, importation and release was carefully applied. In contrast, many intentional and unintentional introductions of plants and phytophagous animals have resulted in very negative effects on the environment. Several early biological control introductions, mostly of generalist, large predators (e.g. vertebrates, birds and toads) and usually not supervised by biological control experts, led to unintended negative effects on native species. For insect biological control executed by experts, examples of unintended, harmful effects are not known. Selected natural enemies are usually specific, mono‐ or oligophagous species of parasitoids and predators. To prevent making mistakes in the future, pre‐introductory evaluation of natural enemies is advocated, including a step where their potential negative effects are studied. Examination of the literature, taxonomic research and host acceptance experiments are used in such studies to estimate negative effects.
Use and registration of macroorganisms for biological crop protection1
Authors: BIGLER F.
Published: April 2008

The use of macroorganisms (insects, mites and entomopathogenic nematodes) for biological pest control is increasing worldwide. Out of 281 products based on bacteria, fungi, viruses, protozoa, nematodes and insects available for crop protection in 1992, 151 products (53.8%) consisted of macroorganisms. In Switzerland, 65.5% of the 58 products registered for biological pest control in 1995 are macroorganisms. According to published literature and personal information, it is estimated that at least 150 species of entomophagous insects and mites are mass‐produced and released worldwide for biological control. While microorganisms are registered similarly to plant protection products, macroorganisms need registration only in a few countries. An increasing tendency towards regulation of macroorganisms for biological control is obvious. Based on the plant protection act of 1986, Switzerland was the first country where registration of macroorganisms became compulsory. The evaluation criteria for registration include a set of information on the bioecology of the organism, experimental data on efficacy, a simple risk assessment for environmental and human hazards and information on evaluation/registration in neighbouring countries. Positive effects of the registration are: (1) inefficacious products are kept away from the market, (2) quality control rules are respected, and (3) environmental risks and possible human hazards are assessed. Disadvantages are higher costs and sometimes delayed implementation of products. Indirect and direct costs for registration can be a serious problem for small producers and for products with minor markets. Therefore, authorities should consider the development of pragmatic and simplified registration procedures for macroorganisms that support efficacious and high‐quality products on the market, minimize environmental risks and yet do not hamper the implementation of new biological products.
Registration of biological pesticides — the UK perspective1
Authors: HAMER A.
Published: April 2008

The approaches that have been used for regulation of biological pesticides in the UK to date are discussed in relation to the expected European system. Biological pesticides are defined under the Control of Pesticides Regulations 1986 as ‘bacteria, protozoa, fungi, viruses and mycoplasmas used for destroying or controlling pests’. The data requirements for biological pesticides are simpler than those for chemical pesticides but take into account special factors such as infectivity, sensitization of users and toxin production. The Plant Protection Products Regulations (1995) implement Directive 91/414/EEC in the UK.
Quantification of biopesticide activity — a rapid survey of methods and standardization problems1
Authors: GUILLON M.
Published: April 2008

Worldwide development of IPM techniques and increased interest in microbial pesticides have brought a wide range of registered products onto the market in many countries. Quality control is the key point for manufacturing companies because of the variable biological nature of the products and constraints concerning their storage life. The technical specifications of such microorganism‐based preparations are rather difficult for end users to understand and there is an urgent need for standardization. The European Committee for Standardization (ECS) has set up a working group to prepare standard guidelines on assessment of the purity, biological activity and stability of microorganism‐based preparations. This paper discusses the measurement of the activity of the three main classes of frequently used microbial pesticides, those of bacterial origin (Bacillus thuringiensis toxin), viral products (insect baculovirus) and fungal products (antagonistic or entomopathogenic).
A comparison of methods for assessing vertical spray distributions from air‐assisted sprayers
Authors: PERGHER G. , GUBIANI R.
Published: April 2008

Three Centres in Friuli (northern Italy) are offering voluntary testing services for vineyard sprayers. Test procedures routinely include the assessment of vertical spray distribution, using special test rigs. The objective of this research was to compare the vertical distributions as obtained from: patternator (a) (rectangular plates); patternator (b) (lamellate spray separator); spherical spray collectors and fluorimetry. The results showed that both patternators greatly underestimated the portion of spray directed above 3.0 m from the ground. The bulk of the spray was constantly found in the height range of 0.5 m to 1.2 m, which was 0.4–0.5 m lower than by the fluorimetric method. Thus, both patternators can produce substantial errors when used to calibrate a vineyard sprayer, and this may explain some unsatisfactory results previously found.
A new field test for molluscicides in vegetable crops
Authors: SPEISER B.
Published: April 2008

Standard methods for assessing the efficacy of molluscicides have been developed for testing products that contain either metaldehyde or carbamates as active substances. Because these methods are not satisfactory for testing other products, a new field test has been developed. In order to maximize slug feeding activity, lettuce is grown in close proximity to a grass sward, and the experimental area is generously watered. Each experimental plot is 3 × 3 m wide and consists of an area of grass sward. The central area (1.25 × 1.25 m) of each plot is harrowed and planted with 9 lettuce seedlings. The plots are arranged in a randomized design with six replicates per treatment. The percentage of leaf area eaten is recorded twice during the first week, and later weekly. From this data, the standardized area under the damage progress curve (AUDPC) is calculated. This is the integral of leaf loss over time and gives a comprehensive overview over the time course of slug damage. At harvest, the number of marketable lettuce heads and their head weight are recorded. Some results of molluscicide trials in 1996 are given. The possibilities for adjusting plot size, choice of crop, number of replicates and number of assessment dates to personal needs are discussed.
Identification of chickpea stunt viruses in Algeria
Authors: AIT YAHIA A. , AIT OUADA M. , HADJARAB K. , BELFENDES R. , SARNI K.
Published: April 2008

Chickpea samples showing viral‐like symptoms of stunting and yellowing were collected from different parts of Algeria. Transmission trials on three species of aphids (Acyrthosiphon pisum, Aphis craccivora and Aphis fabae) to a limited range of hosts, and ELISA tests, led to the identification of bean leaf roll luteovirus. Field sampling also allowed identification, by ELISA and TBIA tests, of two other viruses: a luteovirus closely related to beet western yellows luteovirus, and faba bean necrotic yellows nanavirus. Ten species of aphids were identified by trapping in affected fields, most being previously known vectors of the three viruses concerned.
Incidence of Phomopsis amygdali, Botryosphaeria berengeriana and Valsa cincta diseases in almond under different control strategies 1
Authors: TUSET J. J. , HINAREJOS C. , PORTILLA M. T.
Published: April 2008

The fungi causing cankers and withering of stems and branches of almond under Spanish Mediterranean conditions are: Phomopsis amygdali, Botryosphaeria berengeriana (in the form of its Dothiorella anamorph) and Valsa cincta (anamorph Cytospora cincta). P. amygdali is the most important because of its high specificity. Its development causes serious damage, particularly in orchards near the sea. B. berengeriana is a polyphagous fungus with high virulence but, because its growth depends on high temperature and adequate humidity, it is only present in orchards located in the south of the Iberian peninsula. V. cincta is widespread and causes withering of twigs. Control strategies for these three fungi with systemic fungicides have been investigated in the laboratory and glasshouse by artificial inoculations using both twig segments and seedlings of almond cv. Marcona. Benomyl, thiophanate‐methyl and imazalil applied both as foliar spray and by soil drenching, have shown low fungitoxic activity in the apical part of the stems and twigs of tested plants. P. amygdali and B. berengeriana were the most affected by the three fungicides, while V. cincta was less affected. Benomyl proved to give the best control, followed at a distance by thiophanate‐methyl. No control was obtained with imazalil.
Characterization of Glomerella cingulata isolates from almond fruit using VCG, molecular, fungicide sensitivity and pathogenicity tests 1
Authors: SHABI E. , KATAN T. , FREEMAN S.
Published: April 2008

Almond anthracnose caused by Glomerella cingulata is a major disease of this crop in Israel. The pathogen infects young fruit resulting in fruit rot. Leaf wilting and shoot dieback accompany fruit rot, even though the pathogen cannot be isolated from leaves or twigs. Isolates of G. cingulata from diseased almond fruit were compared using vegetative compatibility grouping (VCG), molecular methods, fungicide sensitivity and pathogenicity assays in order to determine the genetic diversity and host specificity among different populations. Polymerase chain reaction amplification of genomic DNA, using four primers produced uniform banding patterns for all the almond isolates from different geographic locations in Israel. HaeIII digestion patterns of A + T‐rich DNA, and Southern hybridization of the repetitive nuclear DNA element (GcpR1) to PstI‐digested genomic DNA of almond isolates also revealed no polymorphism. Chlorate‐resistant nitrate‐nonutilizing (nit) mutants were generated and used in heterokaryon tests. Complementary heterokaryons formed between the mutants of different isolates indicated a single VCG. Isolates of G. cingulata from almond had optimal growth temperatures of 20–22°C as opposed to 26–28°C for avocado isolates. In addition, almond isolates of G. cingulata are insensitive to benzimidazole fungicides in contrast to sensitivity of isolates from avocado. In artificial inoculations, almond isolates infected almond, avocado, apple, mango and nectarine fruit at a slower rate than G. cingulata isolates from avocado, apple and mango. Only the anamorph Colletotrichum gloeosporioides has been detected on almond in Israel, whereas isolates of G. cingulata from other hosts produce ascocarps.
Economic importance and cycle of Polystigma ochraceum, causing red leaf blotch disease of almond, in Lebanon
Authors: SAAD A. T. , MASANNAT K.
Published: April 2008

The red leaf blotch disease, incited by the pathogen Polystigma ochraceum, is a major disease of almonds in Lebanon. An investigation was conducted to study the severity of the disease in almond‐growing areas of Lebanon and the cycle and developmental stages of the pathogen in an almond orchard in the coastal area. The disease was found to be widespread and severe in the coastal and mountainous areas, moderate in the north, and mild in the interior Bekaa plain. Ascospore discharge began in early February, just before flowering, and continued until mid‐May. Maximum ascospore discharge occurred about one month after flowering. Pycnidia started to form in the stromata when turning red in colour and acquiring a crusty appearance. Perithecial initials appeared later during the month of July, but continued their development and maturation during autumn and winter to start discharging their ascospores in February. The pathogen could not be grown in vitro on culture media. No secondary infections by pycnidiopores were noticed.
Phytophthora crown rot of almonds in Australia 1
Authors: WICKS T. J. , LEE T. C. , SCOTT E. S.
Published: April 2008

Phytophthora crown rot, caused primarily by Phytophthora cambivora, has caused considerable losses in almond orchards in the Willunga and northern plains areas approximately 50 km north and south of Adelaide (AU), respectively. Other Phytophthora species including P. citrophthora, P. cryptogea, P. megasperma and P. syringae have also been associated with diseased trees. Tree losses have been associated with P. cactorum isolated from trunk cankers on scaffold limbs on trees in the Riverland almond‐growing area approximately 350 km north‐east of Adelaide. The Al mating type of P. cambivora was the most pathogenic to almond seedlings. Cvs Mission and Chellaston, which are commonly used as rootstocks, were highly susceptible to crown rot whereas peach cv. Nemaguard was resistant. An excised twig assay has been developed to screen micropropagated shoots for resistance to P. cambivora. Metalaxyl applied at 5 g active substance per tree in spring, winter and autumn in a shallow trench close to the trunk prevented the development of trunk cankers. Foliar sprays of phosphonate (H3PO3) at 2 g active substance per litre in autumn and spring also inhibited canker development.
Serious fungal and bacterial diseases of almond in Greece 1
Authors: ANTONIOU P. P. , TJAMOS E. C. , TOKALIS N.
Published: April 2008

The main fungal and bacterial diseases of almond in Greece are reviewed, with particular attention to phytophthora collar rot and verticillium wilt.
Detection of prunus viruses by print‐capture PCR 1
Authors: CAMBRA M. , OLMOS A. , CANDRESSE T. , GORRIS M. T.
Published: April 2008

A very sensitive and simple procedure has been developed for the preparation of plant samples before PCR amplification using direct tissue printing. This technique was successfully used for the detection of plum pox potyvirus, apple chlorotic leaf spot trichovirus, prunus necrotic ringspot ilarvirus and apple mosaic ilarvirus, in different stone‐fruit material (peach, apricot, plum and almond). The results demonstrate the general applicability of this technique.
Situation of Ralstonia solanacearum in the EPPO region in 1997
Authors: GROUSSET F. , ROY A.‐S. , SMITH I. M.
Published: April 2008

In the early 1990s, Ralstonia solanacearum, an EPPO A2 quarantine pest which previously occurred only sporadically in some of the southern Member Countries, caused a number of outbreaks of potato brown rot over a wider area in the EPPO region. The National Plant Protection Organizations of the EPPO Member Countries concerned have taken action to eradicate the pest, and in particular the European Union has taken joint action through a Control Directive. Eradication has been successful in many cases, but is complicated by the fact that R. solanacearum can persist on wild Solanum dulcamara and be dispersed by water. EPPO has collected information from its Member Countries through the period of the outbreaks and eradication, and presents in this article an overall view and a detailed country‐by‐country situation.