ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01049.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01050.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01051.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The side‐effects of plant protection products on beneficial arthropods have been studied by the Netherlands Plant Protection Service since 1974. Laboratory test methods were developed in the context of IOBC/WPRS forEncarsia formosa, a natural enemy of glasshouse whitefly,Trialeurodes vaporariorum.These methods were elaborated by EPPO into a sequential decision‐making scheme and published as an official EPPO guideline in 1989. The scheme includes a residual toxicity test on adults, a direct contact test on pupae, a persistence test on adults, all in the laboratory, and a field test. Following this guideline, the Netherlands Plant Protection Service tested and evaluated 107 pesticides at 307 concentrations over 10 years. Test details and complete test results are reported, including the risk assessments according to the EPPO scheme and according to the IOBC/WPRS conventions. These results are further summarized per type of pesticide, kind of test and risk classification. The efficiency of the scheme in classifying pesticide concentrations for risk toE. formosais analysed. The scheme was found to be reasonably practical and efficient except for pesticides in the range between safe and hazardous. Suggestions for improvement are given. Also the possible need for changing the original IOBC/WPRS‐criterion for harmlessness (effect<50%) is discussed. No reasons for lowering the criterion to 30% were found. The decision‐making scheme fits into the general approach for environmental risk assessment of plant protection products, developed recently by EPPO and the Council of

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01052.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A variety of systems of designation has evolved to name pathotypes of plant pathogens. The systems were evaluated to determine those best suited for particular purposes. Virulence and avirulence/virulence formulae of pathotypes have advantage over the use of consecutive numbers or letters given in chronological order of pathotype discovery. As soon as pathotype information exceeds a certain level of complexity, mathematical codes are most advantageous, in particular two codes, octal notation and coded triplets. A more universal adoption of the most appropriate codes is recommended to ease communication and comparisons of results.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01053.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

During recent years,Peronospora tabacinahas frequently been intercepted on leaves in lots of imported Greek oriental tobacco at ports of entry in China. The question arises whether such infected leaf debris can be a source of primary inoculum. The present study has examined the pre‐export viability ofP. tabacinaon stored Greek oriental tobacco. Firstly, basic experiments were done: (1) to find a suitable medium (2% Bacto (Difco) agar) forin vitrogermination ofP. tabacinasporangia; (2) to determine the optimum (15–21 °C), maximum (30°C) and minimum (2°C) temperatures for sporangial germination; (3) to devise a suitable method of inoculation for an infectivity test. Secondly, viability tests were done on stored Greek oriental tobacco harvested in 1986 and 1987.In vitrogermination tests and infectivity tests were conducted separately, according to microscopic grading of the apparent turgidity of sporangia and sporangiophores collected from lesions of infected tobacco leaves of different cultivars and crop years. The tests were maintained for a much prolonged incubation period as compared with the controls. Neitherin vitrogermination nor infectivity tests showed any sporangia to be viable. Further work is needed to determine what period of storage is rationally acceptable for both plant quarantine and commercial

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01054.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

There is a real risk of introducingXylella fastidiosainto the EPPO region where this quarantine pest has not yet been found and constitutes a serious threat to the Mediterranean grapevine industry. Direct isolation of endophytic bacteria from imported propagation material, combined with one‐dimensional SDS‐PAGE of the total soluble proteins of the bacterial cell envelope, can be considered as a test to be used in grapevine certification schemes. The gel electrophoretic pattern ofXylella fastidiosais characterized by a constant distribution of 14 major diagnostic bands. Even without gel scanning, this relatively simple technique allows discrimination between grapevine strains ofX. fastidiosaand other xylem‐inhabiting, slow‐growing b

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01055.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Fireblight was first observed in Romania in 1992‐08 near Braila, and shortly after in the pear collection of the Fruit Research Institute in Pitesti‐Maracineni. Advanced symptoms indicated that the disease was present at least one year earlier. Symptomatology, fruit pathogenicity, selective culture media, hypersensitivity, agglutination and fatty acid class analysis confirmed the authenticity of the pathogen asErwinia amylovora.Of the native Romanian fruit cultivars affected, apple cv. Delicios de Voinesti and pear cv. Aromat de Bistrita appear the most susceptible to firebli

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01056.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The literature related to bacterial leaf streak of cereals, due to various pathovars ofXanthomonas campestris, is confusing and dispersed. This review presents a synthesis of the knowledge that has been accumulated on the disease in cereals since the early reports on barley and wheat. The aim is to present the current status on geographical distribution of the disease, to explain possible confusions in symptoms, and to show the limited quantitative information available on losses and on host/pathogen interactions. Disease etiology and means of control are also reviewed. The objective is to define the present situation of black chaff in wheat, barley and triticale, and to delineate the major research needs in these crops. Difficulties in controlling bacterial leaf streak arise as a result of limited epidemiological knowledge and of the absence of satisfactory seed treatment permitting the eradication of the bacterium. There is an urgent need for a seed certification scheme and for more information on genetic resistance, with a view to limiting outbreaks of this sporadic but devastating disease.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01057.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Surveys on the spread of the main pests of plane (Platanusspp.) and on their influence on the decline of this genus in recent years have been carried out in various European countries. Of the primary pests which have been detected,Ceratocystis fimbriataf.sp.platani, agent of canker stain, has spread through several of the northern Mediterranean countries, causing death of trees;Gnomonia platani, agent of anthracnose, has spread mainly in the north‐central Mediterranean areas;Microsphaera platani, agent of powdery mildew, has spread throughout almost all Mediterranean countries; so also has the insectCorythucha ciliata, which causes yellowing of the foliage. On trees declining under the interaction of these pests, secondary pests, agents of bark necrosis and, above all, of wood decay, are often detected.Ganodermaspp. are the main wood‐decaying pathogen and can cause lethal root rots, especially if favoured by various kinds of stress. The trends and interaction of these pests in northern Italy are considered and control measures are discus

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1994.tb01058.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY