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Seed potato production is threatened by potato cyst nematodes (PCN). Seed potatoes can only be grown on PCN-free declared potato fields. A seed potato grower chose inundation, flooding his soil, for controlling PCN because resistant cultivars are economically less advantageous and catch crops or granular fumigants gave insufficient results. Inundation is widely used in bulb cultures in The Netherlands to control parasitic nematodes and selectively also pathogenic fungi. Research was performed on the efficiency of inundation against PCN species Globodera pallida and the causal fungal agent of potato wilt Verticillium dahlia (Vd) in a 30 ha field. The effect on soil fertility and texture was also studied. A technical manual for large-scale inundation was written for growers and economic evaluation was performed. Results showed that after 16 weeks of inundation 99.9% of the contents of artificially applied G. pallida cysts was eliminated. Vitality of V. dahlia was reduced with 84%. Incorporation of B. juncea did not increase efficiency. Anaerobic soil disinfestation (ASD) with incorporated B. juncea in the dike surrounding the field, showed a lower efficiency against G. pallida due to incorrect application. Naturally occurring beet cysts lost their vitality after inundation. Incorporation of B. juncea increased soil suppressiveness against Rhizoctonia solani whereas inundation leveled out this effect. By slow release of water after inundation soil texture remained unchanged. Changes in fertilizer content were affected both by the growth and incorporation of B. juncea and by inundation. An increase of sodium and of the electrical conductivity (EC) was noticed. Inundation proved to be highly effective in controlling PCN and Vd and economically feasible for practical application. Long-term effects have to be monitored and effects on other soil quality aspects, both biological, chemical and physical should be taken into account in future research. For some regions in The Netherlands inundation is a new tool for seed potato growers in their Nematode Control Strategy.

Since the onset of human agriculture thousands of years ago,selection for reduced human toxicity and improved humandigestibility of seeds and tubers has led to crops that are morevulnerable to diseases and pest organisms than their ancestral wildrelatives (Fresco, 2012). For many pests, farmers’ cuisine ispreferred over natures’ cuisine. Wild plants avoid being eaten (byinsects, herbivores and us) while crop plants are made for beingeaten (eaten by us, but also easily by herbivores, insects and fungi).Therefore, pests need to be controlled if people wish to harvest ahigh share of the yield of their crops. In her book Fresco explainsthat people in former times had not so much grip upon theirharvest of food, and food was therefore surrounded by many ritualsand incantations. Only in recent centuries has food productionbecome more reliable, and hunger has almost disappeared in recentdecades.

Voor imkers onderzoekt bijen@wur al jaren bijen- en broedmonsters op een aantal veel voorkomende ziekten. In de laatste 20 jaar zijn bijna 3000 monsters onderzocht. Het herkennen van de symptomen van ziekten blijft een expertise van Bijen@wur, terwijl het beter zou zijn als bijenhouders dat zelf zouden kunnen. Om deze kennis beschikbaar te maken voor bijenhouders, is er dit jaar voor een andere opzet gekozen

Introduction Elms are important trees in urban environments and coastal areas due to their resistance to harsh conditions such as wind, salt, flood, and narrow root space, as well as to their attractive architecture. However, a devastating disease, the so-called Dutch elm disease (DED), appeared in Europe during the 1920s and in North America by 1930. Sudden wilting and dying of the leaves and branches was caused by Ophiostoma ulmi during the first pandemic from 1920s to 1940s, while an even more aggressive strain O. novo-ulmi is responsible for the current pandemic. Elm bark beetles, mainly Scolytus scolytus and S. multistriatus, transmit the disease by breeding in weakened and dead elms (Scheffer et al, 2008). Approximately 100 years after its first introduction into Europe, biological control of Dutch elm disease is an effective component of an integrated control strategy for this disease. Conidiospores of Verticillium albo-atrum isolate WCS850 (active ingredient of Dutch Trig®) enhance the natural defence mechanism of elms after being injected in the xylem tissue of tree, where they germinate and induces resistance (Scheffer, 1990). The isolate was proven to be non-pathogenic for all the 19 tree species that had been tested (http://www.dutchtrig.com/home)

Botrytis leidt in snijbloemen nog steeds tot veel uitval. Resistente rassen zijn niet beschikbaar. Wel zijn er duidelijke verschillen in gevoeligheid tussen cultivars aanwezig. Eén van de manieren om planten zich beter te laten weren tegen Botrytis is om de aanmaak van natuurlijke afweerstoffen te activeren. Kennis over het primen van planten in sierteeltgewassen staat echter nog in de kinderschoenen. In dit onderzoek is onderzocht welke genen, afweereiwitten en plantfenolen een rol spelen bij de afweerprocessen tegen Botrytis.

Genes expressing Bacillus thuringiensis (Bt) toxins have been incorporated into genetically modified (GM) plants to render these resistant to certain insect pests. Of particular interest have been the genes encoding Cry (Crystal) proteins, but also the gene encoding the vegetative insecticidal protein Vip3Aa has been incorporated into crop plants. Over the last decennium, GM events have been crossed through traditional breeding, resulting in stacked GM events expressing several Bt insect resistance genes. Experiments demonstrate that interactions between two or more toxins can either enhance or decrease their activity. It is thus possible that interactions between Bt proteins produced by GM plants occur and thereby influence their effect on non-target invertebrates compared to GM plants expressing just a single Bt gene. This report has been drafted as a response to a call of the Netherlands Commission of Genetic Modification (COGEM) to address two main questions: (1) can interactions between Bt proteins be predicted and (2) to what extent are studies on interactions relevant for risk/safety assessment of GM crops. The questions were tackled from an eco-toxicological angle, in particular taking into account those types of information that are relevant for risk/safety assessment of GM crops. Answering the questions was done by reviewing and considering the current knowledge on the specificity of Bt proteins, on known interactions between Bt proteins and the methods to assess these interactions, and available guidance for risk/safety assessment of GM crops combining multiple Bt proteins. Also the information reviewed in a parallel project addressing the same questions, but from a biochemical and toxicological perspective (Eco¿tat, 2014), was taken into account when formulating conclusions.

As an alternative to MeBr fumigation a 48h Controlled Atmosphere Temperature Treatment (CATT) was developed and scaled up by Wageningen UR in cooperation with the Dutch plant propagating association Plantum. This results in an excellent de-infestation and 99.8 % mortality of the strawberry tarsonemid mite (Phytonemus pallidus). This non-chemical and sustainable method provides a healthy production of highly qualified strawberry runners in the field. From 2009 CATT is up scaled to a commercial level and widely applied by Dutch nurseries. In 2011 this CATT method was successfully modified to eradicate also the root knot nematode Meloidogyne hapla (>99.7% mortality), which was not effectively controlled by MeBr fumigation. For an effective killing of the root knot nematodes, temperature must be raised to 40 ºC. In several experiments the optimum conditions for a high mortality of both tarsonemids and nematodes was studied. This leads into an adapted CATT of 20 hours at a temperature of 35 ºC and 50 % CO2 followed by 20 hours at a temperature of 40 ºC. In 2012 this adapted CATT was successfully upgraded and tested under field conditions. Additional research in 2013 leads to the conclusion that cross infection of plants by the bacterial Q-disease Xanthomonas fragariae during CATT treatment is unlikely

Nederland speelt internationaal een belangrijke rol in productie en handel van plantaardig materiaal. Hierin zijn vaak ongewenste veroorzakers van quarantaine- (Q) en kwaliteitsziekten (K) en -plagen een storende factor. Om de (fytosanitaire) kwaliteit van verhandeld (met name ook geëxporteerd) plantmateriaal ook in de toekomst te kunnen blijven garanderen, en eigen teelten te vrijwaren van ongewenste organismen is het van groot belang vroegtijdig deze plantenpathogenen te kunnen detecteren en te identificeren. Hiervoor zijn gevalideerde onderzoekmethoden noodzakelijk, die geschikt zijn voor routinematig gebruik door het bedrijfsleven, de keuringsdiensten en de NVWA. De hier voorgestelde intensieve samenwerking tussen kennisinstellingen, overheid en keuringslaboratoria is noodzakelijk om de agrarische sector toekomstbestendig te houden. Daarnaast dient naast aandacht voor nieuwe ontwikkelingen ook aandacht besteedt te worden aan kwaliteitsborging en efficiëntie verbetering van bestaande technieken zodat de taken van de keuringsdiensten beter uitgevoerd kunnen worden.

Quarantaine organismen leveren cruciale problemen op in de internationale handel. Ondanks strikte maatregelen en controle worden insecten- en nematodenplagen regelmatig door toenemende internationale handel overgebracht naar niet besmette gebieden. Quarantaine plagen veroorzaken grote economische verliezen en leiden tot handelsbelemmeringen. Sommige kleine insecten zoals trips en witte vliegen of nematoden zijn moeilijk te bestrijden met pesticiden. Fumigatie met ontsmettingsmiddelen was een veel toegepaste methode om quarantaine plagen te bestrijden middels een pre-shipment behandeling. Een van de meest effectieve ontsmettingsmiddelen methylbromide (MeBr) is sinds 2010 niet meer toegelaten in Nederlands vanwege het chadelijke effect op de ozonlaag. Een effectief en milieuvriendelijk alternatief voor MeBr is zeer gewenst. Controlled atmosphere temperature treatment (CATT) is een fysieke behandelingsmethode en heeft een aantoonbaar dodelijk effect op diverse insecten- en nematodenplagen. De CATT methode is een combinatie van lucht en temperatuur over een bepaalde tijdsduur om plagen maximaal af te doden met een minimaal of acceptabel fytotoxisch effect op plantproducten. Dit is een milieuvriendelijke methode en heeft daardoor geen toelating nodig voor toepassing.

In 1990 is in Nederland een werkgroep opgericht om jaarlijks gevallen van massale bijensterfte te inventariseren die volgens getroffen imkers veroorzaakt zijn door blootstelling aan gewasbeschermingsmiddelen (Oomen, 1992). De werkgroep jubileert dit jaar en heeft daarom haar bevindingen met spuitschade in de afgelopen 25 jaar samengevat

Bijen en hommels zijn door hun bouw en gedrag goede bestuivers. Maar ze kunnen meer. Ze zijn ook heel geschikt om antagonistische micro-organismen voor ziektebestrijding over te brengen én informatie vanuit het veld over ziekten mee terug te nemen. Belangrijk voor al deze taken is: hoe houden we ze actief onder de ‘nieuwe’ teeltomstandigheden in de kas?

Uit dit onderzoek is gebleken dat planten die eerder in het seizoen worden geïnfecteerd, bol len geven met een hoger percentage TBV Plan ten die eenmalig een week voor het rooien wor den besmet, geven bijna geen zieke bollen. Bij infectie twee weken en langer voor het rooien loopt het percentage zieke bollen sterk op. Ook worden klisters later ziek dan de hoofdbol. Infec tie vindt blijkbaar plaats vanuit de plant via de hoofdbol naar de klisters. ln de praktijk vindt inl'e tiegedurende hei hele seizo n pla11 door pas r nde, vliegende blad luizen. In de praktijk i du ook ni t va 1 te tel len wanneer planten voor hel er t geïnfecteerd raken. Vrijwel zeker gebeurt dat ook al vroeg in het seizoen. In dat geval is er dus geen spra ke van een lager percentage virus in de kleine maten. De resultaten hebben betrekking op het onder zoek in een cultivar ('Strong Gold') en van een seizoen (2013-2014). Om beter gefundeerde conclusies te kunnen trekken is vervolgonder zoek gestartin het seizoen 2014-2015 met twee cultivars. Het actieplan 'Minder virus in tulp' is een gezamenlijk initiatief van Wageningen UR, PPO Bloembollen, Boomkwekerij & Fruit, Proeftuin Zwaagdijk, KAVB,LTO en BKD.

Plaagwantsen zoals behaarde wants en brandnetelwants vormen in teelten als aubergine, komkommer en chrysant een serieus probleem. Ze geven al in kleine aantallen flinke schade: bloemabortie in aubergine, stengel- en vruchtschade in komkommer en splitkoppen in chrysant. Zodra telers wantsen of wantsenschade signaleren zien ze zich al snel genoodzaakt in te grijpen met middelen die schadelijk zijn voor aanwezige biologische bestrijders tegen andere plagen; het begin van het einde van hun biologie.

Inwinteren is het slotstuk van het bijenjaar, een soort “Grande Finale” na een seizoen hard werken met de bijen. We geven onze bijen voldoende voedsel om de winter goed door te komen en in het voorjaar weer fris en vrolijk aan de slag te kunnen gaan. Gelukkig is het eenvoudig mits er aan enkele voorwaarden voldaan wordt. Waarom winteren we onze bijen in? Simpelweg omdat we de honing, hun ‘dure’ wintervoorraad, geheel of gedeeltelijk afnemen en daar suiker als goedkoop alternatief voor in de plaats geven

In 1990 is in Nederland een werkgroep opgericht om jaarlijks gevallen van massale bijensterfte te inventariseren die volgens getroffen imkers veroorzaakt zijn door blootstelling aan gewasbeschermingsmiddelen (Oomen, 1992). De werkgroep jubileert dit jaar en heeft daarom haar bevindingen met spuitschade in de afgelopen 25 jaar samengevat

Euroblight heeft voor de tweede maal de samenstelling van de phytophthorapopulatie in Europa bepaald. Er zijn minieme verschuivingen

Since its first report in Brazil in 1985, wheat blast, caused by Magnaporthe oryzae (anamorph: Pyricularia oryzae), has become increasingly important in South America, where the disease is still spreading. We used 11 microsatellite loci to elucidate the population structure of the wheat blast pathogen in wheat fields in central-western, southeastern, and southern Brazil. No subdivision was found among the wheat-infecting populations, consistent with high levels of gene flow across a large spatial scale. Although the clonal fraction was relatively high and the two mating type idiomorphs (MAT1-1 and MAT1-2) were not at similar frequencies, the clone-corrected populations from Distrito Federal and Goiás, Minas Triangle, and São Paulo were in gametic equilibrium. Based on these findings, we propose that populations of the wheat blast pathogen exhibit a mixed reproductive system in which sexual reproduction is followed by the local dispersal of clones. Seedling virulence assays with local wheat cultivars differentiated 14 pathotypes in the current population. Detached head virulence assays differentiated eight virulence groups on the same wheat cultivars. There was no correlation between seedling and head reactions.

Tropical race 4 (TR4) of Fusarium oxysporum f. sp. cubense (Foc) is a quarantine pathogen in many banana-producing regions of the world. Preventing further dissemination and precluding incursions into areas where it has not been observed is critical for maintaining local and commercial banana production. Trading of symptomless but infected banana planting material, movement of machinery with adhering infested soil, and the use of traditional banana-based packing material facilitate the spread of Foc. A PCR-based detection tool for TR4 was used to analyze field samples from symptomatic and symptomless banana plants and soils collected in TR4-affected areas. Foc TR4 was detected in all infected samples by conventional or nested PCR analyses. The results will be used to develop and implement TR4 quarantine and management strategies

Summary In this article we provide guidelines on statistical design and analysis of data for all kinds of honey bee research. Guidelines and selection of different methods presented are, at least partly, based on experience. This article can be used: to identify the most suitable analysis for the type of data collected; to optimise one’s experimental design based on the experimental factors to be investigated, samples to be analysed, and the type of data produced; to determine how, where, and when to sample bees from colonies; or just to inspire. Also included are guidelines on presentation and reporting of data, as well as where to find help and which types of software could be useful.

A variety of methods are used in honey bee research and differ depending on the level at which the research is conducted. On an individual level, the handling of individual honey bees, including the queen, larvae and pupae are required. There are different methods for the immobilising, killing and storing as well as determining individual weight of bees. The precise timing of developmental stages is also an important aspect of sampling individuals for experiments. In order to investigate and manipulate functional processes in honey bees, e. g. memory formation and retrieval and gene expression, microinjection is often used. A method that is used by both researchers and beekeepers is the marking of queens that serves not only to help to locate her during her life, but also enables the dating of queens. Creating multiple queen colonies allows the beekeeper to maintain spare queens, increase brood production or ask questions related to reproduction. On colony level, very useful techniques are the measurement of intra hive mortality using dead bee traps, weighing of full hives, collecting pollen and nectar, and digital monitoring of brood development via location recognition. At the population level, estimation of population density is essential to evaluate the health status and using beelines help to locate wild colonies. These methods, described in this paper, are especially valuable when investigating the effects of pesticide applications, environmental pollution and diseases on colony survival.

In recent years, triazole resistance in human Aspergillus diseases appears to have been increasing in several European countries. However, current data on the prevalence of resistance are based on a small number of studies which are only available from a few European countries. If present, triazole resistance can severely limit treatment options since alternatives, which are only available in intravenous form, have been shown to be associated with more side effects and poorer outcomes. Triazole resistance in Aspergillus spp. can evolve during therapy. Several point mutations, particularly in the cyp51A gene, have been associated with the development of resistance. Increasingly however, resistant isolates are also being detected in azole-naive patients. These isolates tend to have a particular genetic alteration consisting of a 34-base pair tandem repeat in the promoter coupled with a point mutation in the cyp51A target gene. This leads to an amino-acid substitution at codon 98 (TR34/L98H) causing multi-azole resistance. In patients whose Aspergillus isolates have developed resistance during azole therapy wildtype isolates, closely related genetically to the resistant isolates, have regularly been recovered from samples taken before the start of therapy or during an earlier phase. To date however, no isogenic isolate with a wild-type phenotype has been recovered from patients infected with an Aspergillus strain carrying the TR34/L98H genetic alteration. This suggests a possible environmental origin of the resistant fungus. This particular resistance mechanism has been observed most frequently in clinical isolates in the Netherlands where it has also been found in the environment. Moreover, the resistance mechanism has been demonstrated in clinical isolates in eight other European countries. Azole fungicides are widely used for crop protection and material preservation in Europe. They protect crops from disease, ensure yields and prevent fungal contamination of produce. It has been proposed that triazole resistance has evolved in the environment and could be driven by the selective pressure of azole fungicides. Although evidence supporting this hypothesis is growing, the link between the environmental use of azole fungicides and the development of triazole resistance in Aspergillus spp. is not yet proven. Triazole therapy has become the established treatment for invasive aspergillosis and is widely used in the treatment of allergic aspergillosis and chronic pulmonary aspergillosis. Antifungal therapy for invasive pulmonary aspergillosis is usually prescribed for a minimum of 6–12 weeks, but often may need to be continued for months depending on the period of immunosuppression. Treatment of allergic aspergillosis and chronic pulmonary aspergillosis may need to continue for years or even throughout a patient’s lifetime. We estimated the burden of allergic, chronic and invasive aspergillosis using population statistics and published literature. Of the 733 million inhabitants in the European region1 [1], at any one time 2 100 000 patients may be suffering from allergic aspergillosis and 240 000 from chronic aspergillosis, that would be an indication for antifungal therapy. For invasive aspergillosis, we have estimated an annual incidence of 63 250 cases, complicating multiple underlying conditions including leukaemia, transplantation, chronic obstructive pulmonary disease (COPD) and medical intensive care. The inability to treat these patients with triazoles due to multi-azole resistance would have significant impact on patient management and associated health costs. Early and thorough investigation of this emerging public health problem is warranted in order to avoid the development and spread of resistance. This report examines current evidence for the environmental origin of resistance in Aspergillus spp. and makes recommendations for further steps to assess the risks and consequences of the environmental usage of azole derivatives. Improved surveillance of clinical isolates, including antifungal susceptibility testing, is the key to a better understanding of the magnitude of this emerging problem. Furthermore, the diagnosis of Aspergillus diseases needs to be improved and molecular methods allowing detection of resistance in culture-negative specimens must be further developed and implemented in laboratory practice. Finally, further environmental and laboratory studies are needed to confirm the environmental hypothesis

Honey bee virus research is an enormously broad area, ranging from subcellular molecular biology through physiology and behaviour, to individual and colony-level symptoms, transmission and epidemiology. The research methods used in virology are therefore equally diverse. This article covers those methods that are very particular to virological research in bees, with numerous cross-referrals to other BEEBOOK papers on more general methods, used in virology as well as other research. At the root of these methods is the realization that viruses at their most primary level inhabit a molecular, subcellular world, which they manipulate and interact with, to produce all higher order phenomena associated with virus infection and disease. Secondly, that viruses operate in an exponential world, while the host operates in a linear world and that much of the understanding and management of viruses hinges on reconciling these fundamental mathematical differences between virus and host. The article concentrates heavily on virus propagation and methods for detection, with minor excursions into surveying, sampling management and background information on the many viruses found in bees.

Multidrug resistance (MDR) is a common trait developed by many organisms to counteract chemicals and/or drugs used against them. The basic MDR mechanism is relying on an overexpressed efflux transport system that actively expulses the toxic agent outside the cell. In fungi, MDR has been extensively studied in Saccharomyces cerevisiae and Candida albicans, but also plant pathogenic fungi are concerned by this phenomenon. In this study, we confirmed a drug efflux based resistance mechanism in two isolates of the septoria leaf blotch agent Mycosphaerella graminicola. Using next generation sequencing approaches, we could demonstrate that the MgMFS1 gene was strongly overexpressed in both isolates. The mutation(s) responsible for the MDR phenotype was mapped to a 38.5 kb genomic fragment on chromosome VII, covering also the MgMFS1 gene. Precise genetic mapping will then identify the mdr mutation(s) leading to MfMFS1 overexpressio Characterization of molecular mechanisms underlying the multi-drug-resistant phenotypes of Mycosphaerella graminicola field isolates. (PDF Download Available). Available from: http://www.researchgate.net/publication/271765795_Characterization_of_molecular_mechanisms_underlying_the_multi-drug-resistant_phenotypes_of_Mycosphaerella_graminicola_field_isolates [accessed Jun 15, 2015]

Multidrug resistance (MDR) is a common trait developed by many organisms to counteract chemicals and/or drugs used against them. The basic MDR mechanism is relying on an overexpressed efflux transport system that actively expulses the toxic agent outside the cell. In fungi, MDR has been extensively studied in Saccharomyces cerevisiae and Candida albicans, but also plant pathogenic fungi are concerned by this phenomenon. In this study, we confirmed a drug efflux based resistance mechanism in two isolates of the septoria leaf blotch agent Mycosphaerella graminicola. Using next generation sequencing approaches, we could demonstrate that the MgMFS1 gene was strongly overexpressed in both isolates. The mutation(s) responsible for the MDR phenotype was mapped to a 38.5 kb genomic fragment on chromosome VII, covering also the MgMFS1 gene. Precise genetic mapping will then identify the mdr mutation(s) leading to MfMFS1 overexpressio Characterization of molecular mechanisms underlying the multi-drug-resistant phenotypes of Mycosphaerella graminicola field isolates. (PDF Download Available). Available from: http://www.researchgate.net/publication/271765795_Characterization_of_molecular_mechanisms_underlying_the_multi-drug-resistant_phenotypes_of_Mycosphaerella_graminicola_field_isolates [accessed Jun 15, 2015]

In recent years, triazole resistance in human Aspergillus diseases appears to have been increasing in several European countries. However, current data on the prevalence of resistance are based on a small number of studies which are only available from a few European countries. If present, triazole resistance can severely limit treatment options since alternatives, which are only available in intravenous form, have been shown to be associated with more side effects and poorer outcomes. Triazole resistance in Aspergillus spp. can evolve during therapy. Several point mutations, particularly in the cyp51A gene, have been associated with the development of resistance. Increasingly however, resistant isolates are also being detected in azole-naive patients. These isolates tend to have a particular genetic alteration consisting of a 34-base pair tandem repeat in the promoter coupled with a point mutation in the cyp51A target gene. This leads to an amino-acid substitution at codon 98 (TR34/L98H) causing multi-azole resistance. In patients whose Aspergillus isolates have developed resistance during azole therapy wildtype isolates, closely related genetically to the resistant isolates, have regularly been recovered from samples taken before the start of therapy or during an earlier phase. To date however, no isogenic isolate with a wild-type phenotype has been recovered from patients infected with an Aspergillus strain carrying the TR34/L98H genetic alteration. This suggests a possible environmental origin of the resistant fungus. This particular resistance mechanism has been observed most frequently in clinical isolates in the Netherlands where it has also been found in the environment. Moreover, the resistance mechanism has been demonstrated in clinical isolates in eight other European countries. Azole fungicides are widely used for crop protection and material preservation in Europe. They protect crops from disease, ensure yields and prevent fungal contamination of produce. It has been proposed that triazole resistance has evolved in the environment and could be driven by the selective pressure of azole fungicides. Although evidence supporting this hypothesis is growing, the link between the environmental use of azole fungicides and the development of triazole resistance in Aspergillus spp. is not yet proven. Triazole therapy has become the established treatment for invasive aspergillosis and is widely used in the treatment of allergic aspergillosis and chronic pulmonary aspergillosis. Antifungal therapy for invasive pulmonary aspergillosis is usually prescribed for a minimum of 6–12 weeks, but often may need to be continued for months depending on the period of immunosuppression. Treatment of allergic aspergillosis and chronic pulmonary aspergillosis may need to continue for years or even throughout a patient’s lifetime. We estimated the burden of allergic, chronic and invasive aspergillosis using population statistics and published literature. Of the 733 million inhabitants in the European region1 [1], at any one time 2 100 000 patients may be suffering from allergic aspergillosis and 240 000 from chronic aspergillosis, that would be an indication for antifungal therapy. For invasive aspergillosis, we have estimated an annual incidence of 63 250 cases, complicating multiple underlying conditions including leukaemia, transplantation, chronic obstructive pulmonary disease (COPD) and medical intensive care. The inability to treat these patients with triazoles due to multi-azole resistance would have significant impact on patient management and associated health costs. Early and thorough investigation of this emerging public health problem is warranted in order to avoid the development and spread of resistance. This report examines current evidence for the environmental origin of resistance in Aspergillus spp. and makes recommendations for further steps to assess the risks and consequences of the environmental usage of azole derivatives. Improved surveillance of clinical isolates, including antifungal susceptibility testing, is the key to a better understanding of the magnitude of this emerging problem. Furthermore, the diagnosis of Aspergillus diseases needs to be improved and molecular methods allowing detection of resistance in culture-negative specimens must be further developed and implemented in laboratory practice. Finally, further environmental and laboratory studies are needed to confirm the environmental hypothesis

Estimating the exposure of honeybees to pesticides on a landscape scale requires models of their spatial foraging behaviour. For this purpose, we developed a mechanistic, energetics-based model for a single day of nectar foraging in complex landscape mosaics. Net energetic efficiency determined resource patch choice. In one version of the model a single optimal patch was selected each hour. In another version, recruitment of foragers was simulated and several patches could be exploited simultaneously. Resource availability changed during the day due to depletion and/or intrinsic properties of the resource (anthesis). The model accounted for the impact of patch distance and size, resource depletion and replenishment, competition with other nectar foragers, and seasonal and diurnal patterns in availability of nectar-providing crops and wild flowers. From the model we derived simple rules for resource patch selection, e.g., for landscapes with mass-flowering crops only, net energetic efficiency would be proportional to the ratio of the energetic content of the nectar divided by distance to the hive. We also determined maximum distances at which resources like oilseed rape and clover were still energetically attractive. We used the model to assess the potential for pesticide exposure dilution in landscapes of different composition and complexity. Dilution means a lower concentration in nectar arriving at the hive compared to the concentration in nectar at a treated field and can result from foraging effort being diverted away from treated fields. Applying the model for all possible hive locations over a large area, distributions of dilution factors were obtained that were characterised by their 90-percentile value. For an area for which detailed spatial data on crops and off-field semi-natural habitats were available, we tested three landscape management scenarios that were expected to lead to exposure dilution: providing alternative resources than the target crop (oilseed rape) in the form of (i) other untreated crop fields, (ii) flower strips of different widths at field edges (off-crop in-field resources), and (iii) resources on off-field (semi-natural) habitats. For both model versions, significant dilution occurred only when alternative resource patches were equal or more attractive than oilseed rape, nearby and numerous and only in case of flower strips and off-field habitats. On an area-base, flower strips were more than one order of magnitude more effective than off-field habitats, the main reason being that flower strips had an optimal location. The two model versions differed in the predicted number of resource patches exploited over the day, but mainly in landscapes with numerous small resource patches. In landscapes consisting of few large resource patches (crop fields) both versions predicted the use of a small number of patches.

Panama disease of banana, caused byFusarium oxysporumf. sp.cubense(Foc), poses a great risk to global banana production. Tropical race 4 (TR4) of Foc, which affects Cavendish bananas as well as many other banana cultivars (Ploetz 2006), was confirmed for the first time outside Southeast Asia in Jordan in 2013 (García-Bastidas et al. 2014). In Pakistan, bananas are produced in the Sindh and Balochistan provinces (91% [31,000 ha] and 9% of the country’s production, respectively). Symptoms ofFusariumwilt, including wilting of leaves and vascular discoloration in rhizomes and pseudostems, were first observed in 2012 in a 2-ha Cavendish plantation in Baoo Pooran (ca. 24°N, 68°E), Sindh Province. By January 2014, approximately 121 ha were affected. In Lebanon, bananas are produced for local consumption and regional export, especially to Syria. Yellowing of leaves and internal vascular discoloration in the pseudostems was first observed in Cavendish plants in October 2013 in the Mansouri and Berghliyeh regions. Thus far, 1 ha has been affected. Infected pseudostem tissue samples from Pakistan and Lebanon were processed for Foc isolation and characterization as described byGarcía-Bastidas et al. (2014). White colonies developed from the surface sterilized (70% ethanol) tissue on Komada’s medium (Leslie and Summerell 2006) and nine single microconidia isolates were generated, four from the Pakistan sample and five from the Lebanon samples and transferred to quarter-strength PDA. All isolates phenotypically resembledF. oxysporum(Leslie and Summerell 2006) and were diagnosed as vegetative compatibility group (VCG) 01213, which was confirmed by PCR, thereby corroborating that VCG01213 only represents TR4 strains (Ploetz 2006). Subsequently, one of the isolates from Pakistan (Pak1.1A) and one isolate each from Mansouri (Leb1.1A) and Berghliyeh (Leb1.2C) in Lebanon were analyzed for pathogenicity. Inoculum production and inoculation were according toDita et al. (2010)by dipping (30 min, 106spores/ml) root-wounded 10-week-old Cavendish cv. Grand Naine plants, which were then placed in sand in 3-liter pots under 28°C, 70% relative humidity, and a 16-h diurnal light periods for 6 weeks. Sets of three plants were each treated with either Pak1.1A, Leb1.1A, Leb1.2C, or TR4 (reference isolate II-5, which was diagnosed as TR4 by PCR and pathogenicity analyses, seeDita et al. 2010). Control sets were each treated with either Foc Race1 (Cruz das Almas, Brazil, seeDita et al. 2010) or water. After 4 weeks, all plants inoculated with the isolates from Pakistan, Lebanon, and TR4 (II-5) produced typical symptoms of Fusarium wilt. After 6 weeks, internal symptoms were recorded and tissue was collected from all plants and plated on Komada’s medium. TR4 was confirmed by PCR from isolates that were recovered from all symptomatic plants. No isolates were recovered from plants infected with Race 1 or the water controls, all of which remained asymptomatic. Thus, we confirm the presence of TR4 in Pakistan and Lebanon and its continued expansion and distribution in Western Asia. Although comparatively limited production areas have been affected to date, increasing damage will undoubtedly occur in these countries in the near future.

De taxuskever blijft een groot knelpunt voor boomkwekers omdat er vrijwel geen middelen meer beschikbaar zijn. Het onderzoek naar traditionele insecticiden levert vooralsnog weinig nieuwe middelen op. Een oud middel van natuurlijke herkomst in een nieuw jasje gestoken, een lokstof en een nieuwe val gaan hier hopelijk verandering in brengen

De taxuskever blijft een groot knelpunt voor boomkwekers omdat er vrijwel geen middelen meer beschikbaar zijn. Het onderzoek naar traditionele insecticiden levert vooralsnog weinig nieuwe middelen op. Een oud middel van natuurlijke herkomst in een nieuw jasje gestoken, een lokstof en een nieuwe val gaan hier hopelijk verandering in brengen

Mogelijke bronnen van besmettingen met het aardappelvirus Y (PVY) in aardappelen. In dit onderzoek is met name gekeken naar de rol van bladluizen als belangrijkste overbrengers (‘vectoren’) van PVY. Daarnaast is gekeken naar het mogelijk voorkomen van het virus in andere planten (m.n. onkruiden).

De effectiviteit van gewasbeschermingsmiddelen is sterk afhankelijk van de mate waarin het middel in contact komt met het insect (de raakkans). Insecten hebben de mogelijkheid om zich te verstoppen. Met lokstoffen zouden insecten uit hun verstopplek kunnen komen waarna ze beter geraakt kunnen worden. Internationaal zijn voorbeelden bekend waarbij lokmiddelen met bestrijdingsmiddel toegepast worden, o.a. tegen rupsen en als bait of als gel. Lokken/verstoren en daarna spuiten is een strategie die voor zover bekend nog weinig wordt toegepast. Wel zijn er veel lokstoffen van insecten op de markt. Onbekend is nu welke toepassingen er al zijn, in ontwikkeling zijn, of kansrijk ontwikkeld kunnen worden in de vollegrondsgroenteteelt. In dit verslag resultaten van onderzoek waarin een overzicht van de huidige stand van zaken en potentiële mogelijkheden van het gebruik van lokstoffen om insecten uit het gewas te lokken (om vervolgens gericht te bestrijden met een insecticide). Daarbij worden de volgende vragen beantwoord: o Welke lokstoffen zijn in gebruik (insecten – gewas)? o Welke lokstoffen zijn in ontwikkeling? o Hoe worden ze toegepast? o Wat is het effect / meerwaarde van de lokstof? o Wat zijn de voor% en nadelen van het gebruik van lokstoffen?

De effectiviteit van gewasbeschermingsmiddelen is sterk afhankelijk van de mate waarin het middel in contact komt met het insect (de raakkans). Insecten hebben de mogelijkheid om zich te verstoppen. Met lokstoffen zouden insecten uit hun verstopplek kunnen komen waarna ze beter geraakt kunnen worden. Internationaal zijn voorbeelden bekend waarbij lokmiddelen met bestrijdingsmiddel toegepast worden, o.a. tegen rupsen en als bait of als gel. Lokken/verstoren en daarna spuiten is een strategie die voor zover bekend nog weinig wordt toegepast. Wel zijn er veel lokstoffen van insecten op de markt. Onbekend is nu welke toepassingen er al zijn, in ontwikkeling zijn, of kansrijk ontwikkeld kunnen worden in de vollegrondsgroenteteelt. In dit verslag resultaten van onderzoek waarin een overzicht van de huidige stand van zaken en potentiële mogelijkheden van het gebruik van lokstoffen om insecten uit het gewas te lokken (om vervolgens gericht te bestrijden met een insecticide). Daarbij worden de volgende vragen beantwoord: o Welke lokstoffen zijn in gebruik (insecten – gewas)? o Welke lokstoffen zijn in ontwikkeling? o Hoe worden ze toegepast? o Wat is het effect / meerwaarde van de lokstof? o Wat zijn de voor% en nadelen van het gebruik van lokstoffen?

Stuifmeel is voor bijen eigenlijk het volledige voedsel, op het energie-aandeel na: daarvoor zorgt de honing. Dat betekent dat stuifmeel de eiwitten (aminozuren), mineralen en vitaminen moet binnen brengen, benevens een paar vetten. Zowel wat betreft de aminozuren (en dan vooral de essentiële aminozuren), de vitaminen, mineralen en vetten bevat bijna geen enkele soort stuifmeel alle voedingscomponenten, en al helemaal niet in de juiste verhouding. Daarom zijn bijen gebaat bij een aanbod van meer soorten stuifmeel tegelijk of in ieder geval bijna gelijktijdig. Stuifmeel wordt wel opgeslagen in het bijenvolk, maar behalve in de herfst is de turnover van stuifmeel groot, langdurige voorraden worden niet aangelegd. Dat impliceert ook dat een standplaats op een moment rijk kan zijn, maar vier weken later arm!

Nederland speelt internationaal een belangrijke rol in productie en handel van plantaardig materiaal. Hierin zijn vaak ongewenste veroorzakers van quarantaine- (Q) en kwaliteitsziekten (K) en -plagen een storende factor. Om de (fytosanitaire) kwaliteit van verhandeld (met name ook geëxporteerd) plantmateriaal ook in de toekomst te kunnen blijven garanderen, en eigen teelten te vrijwaren van ongewenste organismen is het van groot belang vroegtijdig deze plantenpathogenen te kunnen detecteren en te identificeren. Hiervoor zijn gevalideerde onderzoekmethoden noodzakelijk, die geschikt zijn voor routinematig gebruik door het bedrijfsleven, de keuringsdiensten en de NVWA. De hier voorgestelde intensieve samenwerking tussen kennisinstellingen, overheid en keuringslaboratoria is noodzakelijk om de agrarische sector toekomstbestendig te houden. Daarnaast dient naast aandacht voor nieuwe ontwikkelingen ook aandacht besteedt te worden aan kwaliteitsborging en efficiëntie verbetering van bestaande technieken zodat de taken van de keuringsdiensten beter uitgevoerd kunnen worden.

Voor de tweede keer in 10 jaar heeft de kleine bijenkastkever (Aethina tumida) voet aan de grond gekregen in Europa. Een eerste uitbraak in Portugal in 2004 werd snel ingedamd, maar een nieuwe uitbraak in het zuiden van Italië lijkt van permanente aard.

Lang geleden, op 30 oktober 1968, is de werkgroep Bodempathogenen en bodemmicrobiologie opgericht. Op de kop af 46 jaar later, op 30 oktober 2014, hield deze werkgroep haar 89e bijeenkomst in ‘s werelds eerste museum over micro-organismen: Micropia. Dit museum opende onlangs haar deuren en maakt het onzichtbare zichtbaar voor het grote publiek

Since the onset of human agriculture thousands of years ago,selection for reduced human toxicity and improved humandigestibility of seeds and tubers has led to crops that are morevulnerable to diseases and pest organisms than their ancestral wildrelatives (Fresco, 2012). For many pests, farmers’ cuisine ispreferred over natures’ cuisine. Wild plants avoid being eaten (byinsects, herbivores and us) while crop plants are made for beingeaten (eaten by us, but also easily by herbivores, insects and fungi).Therefore, pests need to be controlled if people wish to harvest ahigh share of the yield of their crops. In her book Fresco explainsthat people in former times had not so much grip upon theirharvest of food, and food was therefore surrounded by many ritualsand incantations. Only in recent centuries has food productionbecome more reliable, and hunger has almost disappeared in recentdecades.

In dit project zullen met MIPS nieuwe procedures ontwikkeld worden voor het conditioneren en acclimatiseren van enten van groentengewassen. Met MIPS kunnen de effecten van conditionering en acclimatisering op groei, stress en stressgevoeligheid van de enten in de kas nauwkeurig en snel gemeten worden. Op deze wijze wordt een flink aantal conditionering/acclimatisering combinaties in relatief korte tijd geanalyseerd. Uiteindelijk zal uit deze combinaties een aantal geselecteerd worden voor evaluatie en validatie onder praktijkcondities.

Onder praktijkomstandigheden is, van in een eerder project "Verbetering bedrijfszekerheid van productie van geënt uitgangsmateriaal" ontwikkelde Certigraft-toepassing bij machinaal enten van grote partijen (> 10 000 stuks) tomaten- en komkommerplantjes. Uit eerder onderzoek werd bij enkele groentegewassen waargenomen dat het risico op uitval tijdens enten significant verminderd kan worden door voorbehandeling van de onderstam met een binnen dat project uitontwikkeld, duurzaam product “Certigraft”. In tegenspraak met eerdere waarnemingen bleek Certigraft bij machinale enting van tomaat geen significant effect te hebben op een uitvalpercentage van 10%. Hoewel relatief hoge uitval weliswaar substantiëel verlaagd kan worden door Certigraft-toepassing, wijzen de wisselende resultaten er op dat één of meer onbekende factoren in het entproces hierbij een kennelijk controlerende rol vervullen. Dit betekent voor de praktijk dat het lastig te voorspellen is wanneer toepassing van Certigraft effectief en dus zinvol is.

In dit project zullen met MIPS nieuwe procedures ontwikkeld worden voor het conditioneren en acclimatiseren van enten van groentengewassen. Met MIPS kunnen de effecten van conditionering en acclimatisering op groei, stress en stressgevoeligheid van de enten in de kas nauwkeurig en snel gemeten worden. Op deze wijze wordt een flink aantal conditionering/acclimatisering combinaties in relatief korte tijd geanalyseerd. Uiteindelijk zal uit deze combinaties een aantal geselecteerd worden voor evaluatie en validatie onder praktijkcondities.