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There are neither guidance nor methodology proposed to systematically collect data on antibiotics used as plant protection products, antimicrobial resistance of plant pathogenic bacteria or alternative and innovative treatments for the control of phytopathogenic bacteria, at the worldwide scale level. This is the final report of the project on data collection on antibiotics for control of plant pathogenic bacteria, with the view of reducing risk assessment uncertainties. The project collected and reviewed scientific, grey and patent literature information. This analysis highlighted the lack of publicly easily accessible data on antibiotics as plant protection products. On a worldwide scale, up to 39 countries have been found using antibiotics such as kasugamycin, gentamicin, streptomycin, oxolinic acid, oxytetracycline, validamycin or zhongshengmycin. This analysis also pointed out i) the change of use over time and scale, dependent on practice and legislation changes and ii) the question about the risk for animal and human health lying with antibiotics used in plant production and the possibility to select for complex antibiotic resistance gene vectors. Streptomycin is the antibiotic to which plant pathogenic bacteria are the most often reported as resistant, via several ways of counteracting the effect of this antibiotic. Streptomycin resistance in plant pathogenic bacteria was reported in 18 countries. Globally antibiotic resistance reports arose mainly from the USA, South America and Asia. The report also highlighted alternative control measures, with a few already commercially available and sometimes providing efficient control of the plant pathogenic bacteria, but mostly with a lot under research and development. Data gaps, uncertainties and research needs to improve antibiotic use and resistance risk assessment were also highlighted. Finally, the project stressed the need to raise awareness on the risk of improper use of antibiotics as plant protection products, with an emphasis on capacity building and communication. [ABSTRACT FROM AUTHOR]

Description of the subject. This paper discusses the influence of amplicon length on real-time PCR results. Objectives. The aim of the experiments was to show that amplicon size has an influence on detection. Method. Tests were performed on genomic and plasmid DNA. Double-dye probes and SYBR® Green were used for detection by real-time PCR. Primers were selected in order to produce fragments with increasing sizes. Experiments dealt with two targets: an endogenous target for soybean (part of the lectin gene) and a transgenic target (junction P35S-CTP of the MON40-3-2 soybean). Results. The results show that the kinetics of amplification curves evolve as a function of amplicon length, and smaller amplicons yield a higher level of fluorescence for the plateau phase. DNA degradation within the sample as well as the principles of fluorescence acquisition as a function of the chemistry used can also be factors. Conclusions. It was experimentally shown that the observed effect is linked to the suboptimal elongation temperature used in real-time PCR. Detection using SYBR® Green is less impacted as the loss of efficiency is partially compensated by the greater integration of SYBR® Green molecules in the larger fragments.

Cassava mosaic disease (CMD) is reported as the most important constraint on cassava production in Sub­Saharan Africa. Yield losses of 25­95% are reported. The use of resistant genotypes is one of the components for its integrated management. However its impact on genotype behavior depends on infection period, age of the infected plants, environment and virus species or strain. This study was carried out to assess its impact in farmers' fields and the behavior of 14 genotypes under high epidemic pressure in the Sud­Kivu province, in the East of Democratic Republic of Congo (DRC). Early infections have induced 77.5% to 97.3% of yield losses whereas 44.9 to 80% were recorded for cassava plants infected during thirteenth to twenty­fourth weeks after planting. The highest yield losses were recorded in low altitude where more EACMV­UG and dual infections were reported. Improved resistant genotypes MM96/002, MM96/0157 and MM96/1920 allowed harvesting more than 30 T/ha and didn't show any symptoms whereas MM96/6967 and Mvuama have developed symptoms at harvest. Local landraces were susceptible to CMD and developed symptoms during the whole season until harvest. However two of them, Pharmakina and Cizinduka yielded more than 50 T/ha of tubers and associated symptoms were moderate. Two improved and two local cassava genotypes are recommended in this area always making sure to use healthy cuttings.

The effects of cassava mosaic disease (CMD) on growth and yield components were systematically determined on 14 different cassava genotypes in Yangambi. The results show that the tested cultivars differed significantly in terms of severity of the virus, harvest index and tuber production (P< 0.05). CMD had a variable depressive effect on vegetative development. Stem dimensions were hardly reduced, while the height of cultivars Ponjo (38%) and Mboloko (29%) and Ponjo, Lofiongi, Bangi as the leaf area of cultivar Mboloko were significantly lower. The impact of CMD on yield components was generally greater on local cultivars and insignificant on resistant varieties. The cultivars Mvuazi (TMS I 95/0528), Mahungu (TMS 92/297), 96/1089A and Disanka (TMS I 95/0211) were not affected by mosaic disease, which confirms their field immunity. Ponjo, Lofiongi and Mboloko cultivars were sensitive. This study underlines that Mvuazi (TMS I 95/0528, Mahungu (TMS 92/297), 96/1089A, Mvuama (TMS 83/138), Disanka (TMS I 95/0211), Lueki (TMS 91/377) and Zizila (MV 99/0038) and local cultivars, such as Timolo, Yauma, Ngonga and Bangi, showed resistance to CMD.

Indirect immunofluorescence pathogenicity tests and restriction fragment length polymorphism (RFLP) analysis help examine the genetic diversity among Xanthomonas campestris strains that are pathogenic for small grains. Pathogenicity tests on barley and serological tests reveal similarity among few strains, while they exhibit heterogeneity by RFLP analysis. Pathogenicity tests should be carried out before naming the strains at the pathovar level.

Banana bunchy top virus (BBTV), belonging to the genus Babuvirus, is the most devastating and widespread banana virus. Banana and plantain are major crops in terms of household income and food security in Democratic Republic of Congo (DRC). Despite the large area under banana and plantain cultivation in the country, before this study, the genetic characterization of BBTV isolates had only been undertaken for two provinces. In the study presented here, genetic variation in BBTV was assessed from 52 BBTV isolates collected in five out of 11 provinces in DRC (Bandundu, Bas-Congo, Katanga, Kinshasa and Kasaï Oriental) and in two provinces using sequences previously described in databases. Full genome sequencing of DNA-R components was performed, revealing low genetic variation (98-100 % nucleotide identity) among the BBTV isolates detected. The phylogenetic analyses showed that all the DRC isolates were clustered in the South Pacific clade of BBTV. Based on the coding region for the replication initiator protein, haplotype diversity was estimated to be 0.944 ± 0.013, with 30 haplotypes from 68 isolates in DRC. Such diversity shows a haplotype distribution mainly at the sub-regional level in DRC. In addition, the sequence determination from the whole genome of selected isolates confirmed low genetic variation among isolates from seven DRC provinces (97-100 % nucleotide identity). This study strengthened the hypothesis of a single BBTV introduction some time ago, followed by the spread of the virus in the country. [ABSTRACT FROM AUTHOR]

Biological control by natural enemies could enhance pathogen transmission particularly in systems with simple mechanical transmission. To understand potential risk of pathogen dissemination, experiments were conducted to investigate ability of the green peach aphid, Myzus persicae, and its biological control agent, the parasitoid Aphidius colemani, to externally carry and transmit Pepino mosaic virus (PepMV) to tomato. On average, 53 % of the aphids and 78 % of the parasitoids carried the virus on the surface of their bodies after 2 h of contact. After 72 h of contact, at least 90 % of both insects were contaminated. Virus transmission was observed with M. persicae that were in contact with infected plants for 48 h (10 %) and 72 h (25 %), but no transmission was recorded with contact periods of 8 h or 24 h. Aphidius parasitoids failed to disseminate virus to healthy plants during transmission experiments with naturally and artificially infected parasitoids, despite testing more than 3000 individuals. [ABSTRACT FROM AUTHOR]

Populations of Potato virus Y (PVY) and aphids were characterized in potato seed and stock production fields in southern Belgium (Wallonia) from 2009 to 2012. More than 40 aphid species were identified using yellow pan traps. Four thousands potato leaf samples collected in 87 plots from 29 fields were analysed for the presence and typing of PVY strains by RT-PCR. PVY was detected in 26%, 20% and 60% of the seed plots tested from 2009 to 2011, respectively. A higher prevalence of PVY was observed in plots of stock potatoes (60% in 2010 and 67% in 2011). The N/NTN strain of PVY was predominant, representing 70-99% of the strains. [ABSTRACT FROM AUTHOR]

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Two experiments were conducted to investigate the transmission of the Pepino mosaic virus (PepMV) by the greenhouse whitefly ( Trialeurodes vaporariorum) from tomato to tomato. In the 1:1 system (in which a single virus-contaminated plant was placed next to a healthy plant in a cage containing 469 whiteflies on average) the virus was transmitted to three out of 10 plants. In the 1:4 system (in which a virus-contaminated plant was surrounded by four healthy plants in a cage with 601 whiteflies on average) the virus was transmitted to five out of 32 plants. In order to investigate the mechanism involved in the transmission, the insect bodies were washed to determine the external presence of viral particles. The results showed that the number of PepMV particles carried on whitefly bodies was low, with an average occurrence of 1.33 on the 55 whiteflies tested after the insects were in contact with infected plants for 5 days. This low occurrence was confirmed by observation under microscope, which showed an absence of PepMV-contaminated tomato sap on the insect bodies, suggesting that PepMV transmission by whiteflies could occur when they feed on the plant. [ABSTRACT FROM AUTHOR]

Most plant viruses rely on vector organisms for their plant-to-plant spread. Although there are many different natural vectors, few plant virus-vector systems have been well studied. This review describes our current understanding of virus transmission by aphids, thrips, white-flies, leafhoppers, planthoppers, treehoppers, mites, nematodes, and zoosporic endoparasites. Strategies for control of vectors by host resis-tance, chemicals, and integrated pest management are reviewed. Many gaps in the knowledge of the transmission mechanisms and a lack of available host resistance to vectors are evident. Advances in genome sequencing and molecular technologies will help to address these prob-lems and will allow innovative control methods through interference with vector transmission. Improved knowledge of factors affecting pest and disease spread in different ecosystems for predictive modeling is also needed. Innovative control measures are urgently required because of the increased risks from vector-borne infections that arise from en-vironmental change. [ABSTRACT FROM AUTHOR]

Screening for cassava mosaic begomoviruses (CMBs)-resistance using grafting and whitefly inoculation was performed with local and improved cassava. The onset of symptom appearance and the evolution of Cassava mosaic disease (CMD) varied in function of genotypes and virus inoculation techniques used. Grafting position using cassava as scion or rootstock does not affect CMD display and evolution. No relation was established between the number of whiteflies feeding on each genotype and viral inoculation technique tested. Detopping of young leaves induces triggering effect on CMD expression. PCR and ELISA confirmed the EACMV-UG's preferential transmission by whitefly. Hypothesis of virus replication and cultivars's susceptibility were supported by virus increasing particles in infected cassava. Cultivars Mvuazi (TMSI 95/0528) and 96/1089A are suggested field immune to CMBs; Disanka (TMSI 95/0211), Yauma, Timolo, Bangi, Mahungu (TMS 92/297), Mvuama (TMS 83/138), Lueki (TMS 91/377) and Zizila (MV 99/0038) are CMD-resistant; whereas Ponjo, Lofiongi, Ngonga and Mboloko are susceptible. Our results showed that resistant genotypes may express CMD under high inoculum pressure such as grafting. [ABSTRACT FROM AUTHOR]

Two varieties of melons (Cucumis melo) were treated with two fungicides (carbendazim and maneb) and four insecticides (acetamiprid, cyromazin, imazalil and thiamethoxam) to quantify the effect of household processing on the pesticide residues. To ensure sufficiently high levels of residues in flesh and peel, the most concentrated formulations were applied observing good agricultural practice. The peeling step decreased the concentration of pesticide residues for maneb, imazalil and acetamiprid by more than 90%. Cyromazin, carbendazim and thiamethoxam were reduced by approximately 50%. The reduction of the pesticides could not be fully explained by the systemic character of the pesticides. However, the agricultural practices (time of application), solubility and mode of action (systemic versus contact pesticide) of the pesticides could be used to explain the difference in processing factors for the studied pesticides. Degradation products (melamine and ethylenethiourea) were also investigated in this study, but were not detected. [ABSTRACT FROM PUBLISHER]

Polymyxa graminis f. sp. temperata and P. graminis f. sp. tepida are distinguished on the basis of their specific ribosomal DNA sequences. In order to evaluate whether or not host specialization is associated with the special form, the occurrence of infection of both forms on barley and wheat was studied. P. graminis inocula were obtained from soils collected in Belgium and France. Their ribotypes were characterized using molecular tools specific to P. graminis f. sp. temperata or P. graminis f. sp. tepida such as restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR)-amplified rDNA, nested and multiplex PCR. Both special forms were found in each country and coexisted in some soils. The host specificity of P. graminis special forms for barley and wheat was studied from two soils collected at Gembloux (Belgium) and Chambon-sur-Cisse (France), each infested by bymo- and furoviruses. P. graminis f. sp. temperata is more frequent on barley and P. graminis f. sp. lepida on wheat. Furthermore, the quantification of each form on barley and wheat by two separated real-time quantitative PCR assays confirms the observations on the vector specialization. These results suggest a certain but not exclusive host specificity of P. graminis special forms. [ABSTRACT FROM AUTHOR]

4 hybridoma cell lines (named F1-AA9-D9, F1-AB3-B6, F1-BC7-C1 and F2-CA7-F11) secreting monoclonal antibodies to Xanthomonas campestris pv. undulosa were produced by fusing splenocytes from immunized Lou rats with 1R983F myeloma cells. Whole cells were used both as immunogen and as antigen in ELISA and indirect immunofluorescence tests. The monoclonal antibodies produced reacted positively with X. c. pv. undulosa (38 strains), pv. translucens (3), pv. hordei (3), pv. cerealis (2) and pv. secalis (1). Strains from other pathovars (X. c. pv. arrhenatheri, pv. graminis, pv. manihotis, pv. oryzicola, pv. poae and pv. pruni) and from other species (X. axonopodis, X. ampelina) and genus (Pseudomonas, Erwinia, Clavibacter, wheat saprophytic strains) gave a negative reaction. In comparison, seven polyclonal rabbit antisera showed to be less specific: they reacted with unrelated X campestris pathovars as well as with Pseudomonas strains. Nevertheless, the use of phenol-treated cells in Ouchterlony double immunodiffusion could reduce the effect of cross-reaction for antisera. The detection of X. c. pv. undulosa by indirect immunofluorescence on infected wheat seed lots has already been applied with success. [ABSTRACT FROM AUTHOR]

Abstract: Peanut clump and sugarcane red leaf mottle diseases are caused by viruses of the genus Pecluvirus. Indian peanut clump virus occurs in the Indian sub-continent and Peanut clump virus in West Africa. A feature of these viruses is that they are both seed and soil transmitted. Both modes of transmission contribute to long-term persistence and field spread. Data on seed transmission in pearl millet, virus movement within the plant and virus diversity based on RNA-1 partial sequences are presented. This study emphasizes that pecluviruses are also viruses of cereals infecting sorghum and pearl millet, and highlights a correlation between the countries cultivating these two crops and the virus distribution. Ways of controlling pecluviruses and their vector, Polymyxa graminis, taking into account the virus dissemination routes, are proposed. [Copyright &y& Elsevier]

In order to assess the occurrence of Wheat spindle streak mosaic virus (WSSMV) in Belgium, a reverse-transcription polymerase chain reaction (RT-PCR) was developed, targeting WSSMV isolates from Canada, France, Germany, Italy, and the United States. The primers also were designed for virus quantification by real-time RT-PCR with SYBR-Green. No cross-reaction with soilborne cereal viruses such as Barley mild mosaic virus, Barley yellow mosaic virus, Soil- borne cereal mosaic virus, and Soil-borne wheat mosaic virus was observed. The RT-PCR and real-time quantitative RT-PCR allowed a more sensitive detection of WSSMV than enzyme- linked immunosorbent assay. The incidence of WSSMV in Belgium was evaluated using a bioassay with wheat cvs. Cezanne and Savannah and rye cv. Halo, grown in 104 Belgian soils. The presence of WSSMV was detected from plants grown in 32% of the soils. The RT-PCR methods developed here, combined with large sampling, allowed WSSMV to be detected for the first time in Belgium. The real-time quantitative RT-PCR was developed as a tool for evaluating the resistance to WSSMV by quantifying the virus concentration in wheat cultivars. [ABSTRACT FROM AUTHOR]