Julio Javier Diez

Universidad de Valladolid | UVA · Department of Vegetal Production and Forestry Resources

The western conifer seed bug (Leptoglossus occidentalis Heidemann, 1910, Heteroptera: Coreidae) has a significant economic impact due to the reduction in the quality and viability of conifer seed crops; it can feed on up to 40 different species of conifers, showing a clear predilection for Pinus pinea L. in Europe. Its incidence is especially relev...

Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fun...

Fusarium circinatum, a fungal pathogen deadly to many Pinus species, can cause significant economic and ecological losses, especially if it were to become more widely established in Europe. Early detection tools with high-throughput capacity can increase our readiness to implement mitigation actions against new incursions. This study sought to deve...

Introduction Mediterranean forests are currently facing a surge in abiotic stressors such as droughts and massive fires as a result of climate crisis and human pressure. Susceptibility to biotic stressors has also increased, including a variety of pests and pathogens capable of weakening and potentially killing forest flora. Biodiversity of microbi...

The effect of inoculation with Fusarium circinatum on survival of seed and seedlings of 19 populations of Pinus sylvestris was examined under environmentally controlled conditions, with four treatments (0, 50, 103, 106 spores ml−1). A single seed source of P. radiata was included as a positive control. Germination (emergence of the plumule above th...

Background One of the most promising strategies of Pine Pitch Canker (PPC) management is the use of reproductive plant material resistant to the disease. Understanding the complexity of plant transcriptome that underlies the defence to the causal agent Fusarium circinatum , would greatly facilitate the development of an accurate breeding program. L...

International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm gene...

International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm gene...

Pine pitch canker (PPC) is a serious disease of Pinus spp. and Pseudotsuga menziesii globally. The infection of its causal agent, Fusarium circinatum, causes pitch or resin-soaked cankers on trunks and lateral branches of mature hosts. In nurseries, the main symptoms are damping off and tip dieback of seedlings. However, the pathogen, with a hemibi...

Fusarium circinatum is a serious invasive pathogen affecting conifers and causes the disease commonly known as pine pitch canker. Due to the outbreak in European countries, regulations stipulate that Member States must conduct annual official surveys for the fungus on their territory and report the results to the European Commission. Here, we descr...

The factors shaping the composition of microbial communities in trees remain poorly understood. We evaluated whether the core and satellite fungal communities in five pine species (Pinus radiata, Pinus pinaster, Pinus sylvestris, Pinus nigra, and Pinus uncinata) were shaped by the host species identity. Because the trees had earlier been inoculated...

The identification and the functional prediction of lncRNAs require the use of different bioinformatics approaches that result especially challenging for non-model organisms such as Pinus radiata. In this study, transcriptomic identification of lncRNAs was carried out using strand-specific paired-end RNA sequencing, from Pinus radiata samples inocu...

band and brown spot needle blights. Needles showing spots and/or bands with fruiting bodies were sampled. From 25 pine trees samples, 82 fungal isolates were successfully retrieved. The most common fungal genera were Pestalotiopsis (42.68%, n = 35), Rhizos-phaera (28.04%, n = 23) and Cladosporium (9.75%, n = 8). Seven isolates could not be assigned...

This study investigated the complex phenotypic and genetic response of Monterey pine (Pinus radiata) seedlings to co-infections by F. circinatum, the causal agent of pine pitch canker disease, and the oomycetes Phytophthora xcambivora and P. parvispora. Monterey pine seedlings were wound-inoculated with each single pathogen and with the combination...

One of the most promising strategies of Pine Pitch Canker (PPC) management is the use of reproductive plant material resistant to the disease. Understanding the complexity of plant transcriptome that underlies the defence to the causal agent Fusarium circinatum , would greatly facilitate the development of an accurate breeding program. Long non-cod...

Fusarium circinatum causes one of the most important diseases of conifers worldwide, the pine pitch canker (PPC). However, no effective field intervention measures aiming to control or eradicate PPC are available. Due to the variation in host genetic resistance, the development of resistant varieties is postulated as a viable and promising strategy...

Mycoviruses are known to be difficult to cure in fungi but their spontaneous loss occurs commonly. The unexpected disappearance of mycoviruses can be explained by diverse reasons, from methodological procedures to biological events such as posttranscriptional silencing machinery. The long-term effects of a virus infection on the host organism have...

A survey of the native parasitoid community was conducted to characterize its possible use as biological control for Asian Chestnut Gall Wasp (ACGW) at two sampling sites in northern Spain. To this end, 500 ACGW galls were collected over five sampling dates between May and July 2017; 250 of them were dissected to estimate the parasitism rates and t...

Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of trees, from emerging seedlings to mature trees. Despite the importance of PPC, the glob...

Fusarium circinatum is the causal agent of pitch canker, a lethal disease of pine and other conifers. Since F. circinatum is a quarantine organism, its timely detection could efficiently prevent its introduction into new areas or facilitate spread management in already infected sites. In this study, we developed a sequence-specific probe loop-media...

Pines are major components of native forests and plantations in Europe, where they have both economic significance and an important ecological role. Diseases of pines are mainly caused by fungal and oomycete pathogens, and can significantly reduce the survival, vigor, and yield of both individual trees and entire stands or plantations. Pine pitch c...

Fusarium circinatum (Nirenberg and O' Donnell) is the causal agent of pine pitch canker (PPC) disease, one of the most devastating forest diseases worldwide. Long-distance spread occurs mainly through the movement of infected seeds whereas at regional level, the movement of seedlings, substrates, or containers may play an important role in fungal d...

Fusarium circinatum Nirenberg & O'Donnel is listed among the species recommended for regulation as quarantine pests in Europe. Over 60 Pinus species are susceptible to the pathogen and it also causes disease on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and species in genera such as Picea and Larix. The European Food Safety Authority consid...

Dryocosmus kuriphilus is a non-native pest that has recently spread through Europe with a special incidence along the Mediterranean Basin. The presence of this exotic wasp (originally from Asia) threatens stands and orchards of sweet chestnut (Castanea sativa Mill.) as it reduces tree growth and consequently fruit production. In this study the livi...

Pine pitch canker (PPC), caused by Fusarium circinatum, affects Pinus species worldwide. Although no effective solutions have yet been found to control it, there is a growing interest in using biological control agents (BCA) such as Trichoderma to avoid the application of chemical‐based products. Using species with an increasing level of susceptibi...

Pine pitch canker (PPC), caused by the pathogenic fungus Fusarium circinatum (Nirenberg and O' Donnell), is a serious threat to pine forests globally. The recent introduction of the pathogen 2 of 34 to Southern Europe and its spread in Mediterranean region is alarming considering the immense ecological and economic importance of pines in the region...

The fungal pathogen Fusarium circinatum (Nirenberg and O’ Donnell) is the causal agent of pine pitch canker (PPC) disease, which seriously afects conifer species in forests and nurseries worldwide. In Europe, PPC is only established in the Iberian Peninsula; however, it is presumed that its range could expand through the continent in the near futur...

The fungal pathogen Fusarium circinatum (Nirenberg and O' Donnell) is the causal agent of pine pitch canker (PPC) disease, which seriously affects conifer species in forests and nurseries worldwide. In Europe, PPC is only established in the Iberian Peninsula; however, it is presumed that its range could expand through the continent in the near futu...

Fusarium circinatum is a harmful pathogenic fungus mostly attacking Pinus species and also Pseudotsuga menziesii, causing cankers in trees of all ages, damping-off in seedlings, and mortality in cuttings and mother plants for clonal production. This fungus is listed as a quarantine pest in several parts of the world and the trade of potentially con...

Fusarium circinatum is the causal agent of pine pitch canker disease (PPC), affecting Pinus species and other conifers (i.e., Pseudotsuga menziesii (Mirb.) Franco.), forming resinous cankers on the main stem and branches and causing dieback in the terminal guide. This pathogen is spreading worldwide, causing economic losses by converting plantation...

Here, we report the findings of the first trial investigating the susceptibility of Polish provenances of Scots pine, P. sylvestris L., to infection by F. circinatum.

Fusarium circinatum is a highly virulent invasive pathogen that causes the disease commonly known as Pine Pitch Canker (PPC). On mature trees, the most common symptoms of PPC include resin bleeding, resinous cankers, wilting of needles and dieback. In nurseries the main symptoms are yellowish needles, and wilting of foliage and shoots. PPC is consi...

Fusarium spp., as well as other endophytic or pathogenic fungi that form communities, have been reported to be phoretically associated with bark beetles (Coleoptera; Scolytinae) worldwide. This applies to Fusarium circinatum Nirenberg and O’Donnell, the causal agent of pine pitch canker (PPC), which threatens Pinus radiata D. Don plantations in nor...

Pine pitch canker (PPC) is a major threat to pine forests worldwide because of the extensive tree deaths, reduced growth, and degradation of timber quality caused by it. Furthermore, the aggressive fungus responsible for this disease (Fusarium circinatum) can also infect pine seeds, causing damping-off in young seedlings. This study proposes an app...

Fusarium circinatum is the causal agent of pine pitch canker (PPC), one of the most devastating forest diseases worldwide. This fungus causes severe damping-off in pine seedlings and growth reduction, wilting and the development of cankers in pine forests and plantations. A draft of the complete genome sequence of this phytopathogen was recently ma...

To anticipate European climate scenarios for the end of the century, we explored the climate gradient within the REINFFORCE (RÉseau INFrastructure de recherche pour le suivi et l’adaptation des FORêts au Changement climatiquE) arboreta network, established in 38 sites between latitudes 37° and 57°, where 33 tree species are represented. We aim to d...

Eucalyptus globulus plantations are threatened by a defoliator weevil, Gonipterus platensis, which is responsible for the loss of high volumes of timber, especially in Portugal and the north of Spain. Assessing defoliation levels is crucial for predicting wood loss and undertaking pest control and forest management decisions. Harnessing the advant...

The fungal pathogen Fusarium circinatum is the causal agent of Pine Pitch Canker (PPC), a disease which seriously affects different species of pine in forests and nurseries worldwide. In Europe, the fungus affects pines in northern Spain and Portugal, and it has also been detected in France and Italy. Here, we report the findings of the first trial...

Poster contributed to EMBO Workshop. Viruses of Microbes (Wroclaw, Poland)

Pine Pitch Canker disease, caused by the pathogenic fungus Fusarium circinatum, affects conifer species worldwide. However, the virulence of the pathogen may be affected by the presence of mycoviruses. The aim of this laboratory-based study was to investigate the probability and rate of transmission of F. circinatum mitoviruses FcMV1 and FcMV2-2 vi...

Deep sequencing of small RNAs has proved effective in the diagnosis of mycovirus infections. In this study, the presence of mycoviruses in ten isolates of the phytopathogenic fungus Fusarium circinatum was investigated by high-throughput sequencing (HTS) of small RNAs. The contigs resulting from de novo assembly of the reads were aligned to viral g...

Twenty-one isolates of edible ectomycorrhizal fungi (ECM) of 15 different species were tested in vitro for mycelial growth and spore germination against two isolates each of Fusarium oxysporum and F. verticillioides. The growth of Fusarium isolates was significantly inhibited when co-cultured with most of the 21 ECM fungi tested. Two ECM fungi (Ba-...

Two isolates of the edible ectomycorrhizal fungi (ECM), Lactarius deliciosus and Rhizopogon roseolus, were tested against Fusarium oxysporum and F. verticillioides, causal agents of damping-off on seeds and seedlings of Scots pine (Pinus sylvestris) and stone pine (Pinus pinea). The effects of ECM on Fusarium spp. in the rhizosphere of Scots and st...

The Pine Pitch Canker disease caused by the pathogenic fungus Fusarium circinatum is one of the most devastating diseases in pine forests, afforestation and nurseries around the world. Despite the importance of this phytopathogen, only a little is known about the genes that drive the infection traits and the virulence factors. In this work, five ca...

There is a growing necessity to replace chemical agents with ecofriendly materials, arising from the impact on the environment and/or human health, which calls for the design of new broad-spectrum fungicides. In this work, chitosan oligomers (COs), propolis (Ps) and silver nanoparticles (AgNPs) mixtures in solution were assessed to control the grow...

Pine pitch canker (PPC), caused by Fusarium circinatum, is considered among the most important diseases affecting pines in many locations throughout the world. In Europe, F. circinatum is currently present in the Iberian Peninsula, posing a high risk of its spread into currently disease-free countries in Europe. In the present study, susceptibility...

The Asian chestnut gall wasp (ACGW), Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cyn-ipidae) is one of the most important pests in Castanea species worldwide. In 2012, it was found for the first time in Catalonia (Spain) and a year later, in the north of Spain (Cantabria). Today, it is present in 14 Spanish provinces. In search of biological cont...

Aim of the study: To assess the impact on two mycoviruses recently described in F. circinatum mitovirus 1, and 2-2 (FcMV1 and FcMV2-2) on i) mycelial growth, ii) spore germination and iii) relative necrosis. Material and methods: Fourteen monosporic strains of F. circinatum (one of each pair infected with mycoviruses and the other without them) of...

Fusarium circinatum, the causal of pine pitch canker disease (PPC), is now considered among the most important pathogens of Pinaceae in the world. Although in Europe PPC is only established in the Iberian Peninsula, the potential endangered areas cover over 10 million hectares under the current host distribution and climatic conditions. It is there...

La enfermedad del Chancro Resinoso del Pino (CRP) es en la actualidad, una enfermedad extendida a nivel mundial. El organismo causante de dicha enfermedad es un hongo ascomicete denominado Fusarium circinatum, mientras que el hospedante más susceptible a ésta es Pinus radiata. En junio de 2012 se realizó la plantación de un total de 1500 plantas de...

Gremmeniella abietina es un hongo patógeno que produce daños severos en bosques de coníferas en el hemisferio norte. En España, se aisló en 2001 de pies sintomáticos de pino carrasco. En ese año, se evaluaron 37 masas en los alrededores de la zona de detección para conocer la distribución del patógeno. Se encontraron cuerpos de fructificación en 5...

Since its initial discovery in 1945, pitch canker caused by Gibberella circinata (anamorph Fusarium circinatum) has become one of the most important pine diseases in the world. It infests 57 pine species (including Pinussyhestris) and Douglas-fir. F. circinatum has been reported in both nurseries and forests on all continents except Australia and O...

Bark beetles (Coleoptera, Scolytinae) carry a diverse filamentous fungal community sometimes acting as vectors or carriers of phytopathogens. In this study, mycobiota carried by two Tomicus species (Tomicus piniperda and Tomicus destruens) were investigated through (i) morphological and molecular identification of taxa; (ii) taxonomic richness, div...

Climate Change over the last century has created concern to the scientific community, as it could have a major impact on natural and social systems at local, regional and national scales. Greenhouse gasses emission has been modifying global climate, affecting ecosystems in very diverse ways (FAO 2012). Current mitigation policies derived from Kyoto...

Forest ecosystems are characterized by their structural complexity and biodiversity and trophic relationships within them commonly involve several levels. Functioning of these systems is likely to be perturbed in many ways if significant warming predicted eventually occurs. Among the interactions to be shifted by temperature increments in the Medit...

The ecological importance of riparian forests is well known. However, these forest habitats have been disturbed by human activities over the past century as a result of the introduction of flow regulations. Mortality of the riparian alder population caused by Phytophthora has become an important issue in Europe in the past two decades. The main obj...

Fusarium circinatum is the causal agent of pitch canker disease affecting Pinus spp. and Pseudotsuga menziesii worldwide. Under strict quarantine measures, alternative approaches for disease control are necessary. Phosphite (Phi) salts are known for their fungicidal activity and as plant resistance elicitors; however, its potential is yet to be ack...

Los tejidos internos de las plantas (de todas las estudiadas hasta ahora) están habitados por microorganismos endófitos, que los colonizan de modo asintomático, al menos durante parte de su vida (Carroll, 1988). Este grupo de microorganismos está compuesto principalmente por hongos y bacterias. La función ecológica de algunos de estos endófitos ha...

Fusarium circinatum is an ascomycete fungus that causes Pine Pitch Canker (PPC) of pines. The disease is causing damages in forests and nurseries all around the world. In Europe, is present in northern Spain, and also has been detected in Portugal, France and Italy. Fusarium circinatum seems to require fresh wounds on trees as infection court. Notw...

Teratosphaeria nubilosa severely affects young plantations of Eucalyptus globulus and Eucalyptus maidenii in Uruguay. This work analyzes the effect of the damage caused by T. nubilosa on tree growth and survival of E. globulus and E. maidenii, based on data from a trial naturally infected by this pathogen. The effect of defoliation and proportion o...