Dwarf mistletoe (Arceuthobium spp.,Viscaceae) (DM), a hemiparasitic plant, is nutritionally dependent upon its host tree and causes tree mortality in forests worldwide. Dwarf mistletoe infection results in physiological changes in the host, eventually causing the death of the host tree. In this study, we evaluated the changes in leaf reflectance of spruce trees, Picea crassifolia, infected by DM (Arceuthobium

Walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is one of the most detrimental diseases affecting walnut quality and production. A screen of 18 walnut genotypes for leaf resistance to Xaj suggested species independent variation and revealed four highly resistant (HR) cultivars (‘96’, ‘91’, ‘Chuanzao2’ and ‘Qingxiang’), while ‘Yanyuanzao’ and ‘Xiangling’ were highly susceptible (HS)

Snow mold fungi cause serious damage to the seedlings of some coniferous species in the boreal region where deep snow covers the seedlings in winter. Racodium therryanum is one of the fungi causing such damage in Japan. Neither sexual nor asexual spores of R. therryanum have been found in the field, and thus, the taxonomy and life cycle of this fungus is unclear. In this study, we developed seven microsatellite

Tubakia species are fungi causing leaf spots and blights and are reported worldwide, mainly in Asia, Europe and North America. These diseases often occur on Quercus (oak) trees, which constitute one of the dominant broad‐leaved tree genera in the world, so forest structure, function and dynamics could be affected by Tubakia infection. However, few data about the negative impacts of Tubakia on key leaf

Dwarf mistletoes (Arceuthobium species) are arboreal, hemiparasitic plants of conifers that can change the structure and function of the tree crown. Hemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) principally parasitizes western hemlock (Tsuga heterophylla) and effects 10.8% of all western hemlock trees in Oregon, USA. In this study, we climbed 16 western hemlock trees (age 97–321 years

Sandal (Santalum album) is an important forest tree that has been utilized for centuries, valued for its wood and scented essential oil derived from the heartwood. Sandalwood spike disease (SSD) is one of the most destructive problems that affect Indian sandalwood. In 1969, three research groups confirmed that the causal agent of SSD was a phytoplasma. Although research literature on sandalwood spike

Traditional screening of American elm (Ulmus americana) for resistance to Dutch elm disease (DED) often requires many years between initial propagation of trees and inoculation of older trees in the field. Previously published studies have found an association between smaller vessel diameters and increased resistance to DED, but further validation was needed to determine whether it could provide a

Constitutive and inducible terpene production is involved in conifer resistance against insects and fungal infestations. To gain knowledge about local defence responses of Norway spruce bark against pathogens and to find potential chemical markers for resistance breeding, we inoculated the stem of 8‐year‐old Norway spruce (Picea abies) clonal trees with both Endoconidiophora polonica (Ep, a common

A survey for Bursaphelenchus species was carried out in broadleaf forest sites of İzmit Forest Management Directorate. Nematodes were extracted from 128 wood samples, and 22 of them were cultured. Nematodes were identified using morphological characteristics and molecular analysis by amplifying D2‐D3 LSU with primers. Only one Bursaphelenchus species, Bursaphelenchus mucronatus kolymensis, was isolated

Nothophaeocryptopus gaeumannii causes Swiss needle cast disease in Douglas‐fir forest trees and ornamental plantations. This study analysed disease and pathogen behaviour from summer 2011 to spring 2012. An untreated plot within a Pseudotsuga menziesii var. glauca plantation in Valle de Bravo, Mexico was divided into 12 sub‐plots. At each sampling date, needles were collected from four trees per sub‐plot

The diversity of vegetative compatibility (vc) types of chestnut blight fungus, Cryphonectria parasitica, has been reported to be very low in all of Turkey, except in the eastern Black Sea Region. However, risk for increase in vc type diversity has been pointed out regarding the emergence of new vc types as recombinants during sexual reproduction. In this study, the potential increase in the diversity

A conceptual framework for evaluation of climate effects on tree diseases is presented. Climate can exacerbate tree diseases by favouring pathogen biology, including reproduction and infection processes. Climatic conditions can also cause abiotic disease—direct stress or mortality when trees’ physiological limits are exceeded. When stress is sublethal, weakened trees may subsequently be killed by secondary

Two‐year‐old interior Douglas‐fir seedlings in a greenhouse were artificially inoculated with Coniferiporia sulphurascens and grown for four years. The study population included 2,261 seedlings from 94 half‐sibling families distributed across four breeding zones. There was little mortality over the 4 years, but there was advanced stain internally at the root collar from infection by the fungus indicating

Quantification of total phenolic compounds in the heartwood of Picea abies using the Folin–Ciocalteu methods showed that concentrations of phenolic compounds in the heart‐ and sapwood of Picea abies varied, depending on the decay class to which boles were allocated. In the heartwood, mean phenolic concentration was 3.28 mg/g, compared with 2.44 mg/g in sapwood. Experiments using different concentrations

Dieback and trunk canker symptoms were observed on centenarian plane trees (Platanus orientalis) in Gezi Park and Dolmabahçe Avenue in İstanbul province of Turkey in August 2015. Reddish‐brown canker lesions covered approximately half of the tree trunk, from roots to top of the trees. The external symptoms were chlorosis, defoliation and dieback, and most of the affected trees were leafless. Three

Brown spot needle blight, caused by Lecanosticta acicola, is a serious disease of pines worldwide and has become of great concern in Europe over the last decade, with significantly increased outbreaks in pine forests. We examined native and non‐native Pinaceae taxa (four Cedrus and 24 Pinus) in the Atatürk Arboretum, Istanbul, Turkey, for the presence of L. acicola. Needles were sampled from 37 trees

Teratosphaeria foliar pathogens cause leaf and shoot blight on Eucalyptus trees in many parts of the world. Among them, T. destructans is one of the most aggressive pathogens causing defoliation of young Eucalyptus trees in tropic regions. Identification of T. destructans to species level is currently not possible based solely on morphological characteristics or ITS sequence data. The aim of this study

In western Ukraine, forest decline and dieback of several broadleaved tree species have become increasingly evident during recent years, and surveys in some areas have shown symptoms indicative of Phytophthora infections. In this study, we aimed to determine the occurrence and diversity of Phytophthora species associated with several broadleaved tree species (Alnus glutinosa, Betula pendula, Castanea

A historical outbreak of needle blight disease was recorded during 2018 to 2019 in plantations of Pinus radiata and Pinus nigra in the North of Spain. The main pathogens involved in this historical outbreak were identified as Lecanosticta acicola and Dothistroma septosporum. Recently, a variety of tree species in three arboreta planted between 2011 and 2013 in the Basque Country as part of the European

Root disease pathogens, including Armillaria, are a leading cause of growth loss and tree mortality in forest ecosystems of North America. Armillaria spp. have a wide host range and can cause significant reductions in tree growth that may lead to mortality. DNA sequence comparisons and phylogenetic studies have allowed a better understanding of Armillaria spp. taxonomic diversity. Genetic sequencing

Eucalyptus spp. and their hybrids are frequently cloned and mass planted across farmland tracts and commercial plantations in northern India. It is a viable feeder species to the paper and pulp industries in this region. In 2018 and 2019, during field surveys conducted in northern India, a serious leaf blight disease was frequently observed in E. tereticornis plantations. Isolation from the blighted

The mode of persistence of Phytophthora cinnamomi, a highly aggressive soil‐ and water‐borne pathogen, remains unclear. This study investigated the survival of viable oospores and chlamydospores of P. cinnamomi when present as free propagules in untreated soil, or in soil subject to four exogenous treatments: smoke water, fish emulsion and two fungicides (ridomil and furalaxyl). The exogenous treatments

English walnut (Juglans regia) is an important nut crop worldwide and is currently considered emerging in Italy. Botryosphaeriaceae fungi cause symptoms including cankers, discoloration and dieback, and several species are reported across the world on walnut. In this study, symptomatic trees from an orchard in Southern Italy showing branch dieback, cankers, wood discoloration and gummosis were surveyed

Stands of the landscape‐dominant tree, Metrosideros polymorpha (‘ōhi‘a) on the Island of Hawai‘i, HI., USA, are dying from a phenomenon known as rapid ‘ōhi‘a death (ROD). Approximately 180,000 acres of forest have already been impacted by the disease, the majority of which is attributed to C. lukuohia, the more aggressive of the two Ceratocystis species responsible for ROD. Three isolates of C. lukuohia

Hymenoscyphus fraxineus, the causal agent of common ash dieback, possesses a low level of genetic diversity in Europe. The introduction of novel strains of this fungus must be prevented, due to the possible emergence of new virulence alleles, which could result in the infestation of the small proportion of hitherto resistant or tolerant ash trees. More comprehensive knowledge of the host spectrum of

Lawson cypress (Chamaecyparis lawsoniana), an important landscape tree, is widely planted in gardens and parks throughout Iran. Crown gall disease on Lawson cypress trees was observed in Sari and Juybar Counties, Mazandaran province, northern Iran, in 2017. Isolation from galls on potato dextrose agar (PDA) containing CaCO3 yielded bacterial colonies, the predominant types of which were purified and

Dothistroma needle blight (DNB) caused by the ascomycetous fungus Dothistroma septosporum is an important pine disease in Europe. In this study, we determined the distribution and abundance of D. septosporum in local Scots pine forests and plantations in Lithuania and neighbouring Belarus by combining morphological observations and molecular tools. This is the first valid report on the occurrence of

During the annual monitoring surveys for the pinewood nematodes, Bursaphelenchus xylophilus, conducted in the Tuscany region (Central Italy) from the year 2015 to 2019, a total of 1,025 wood samples were collected from symptomatic plants in coniferous forests. Among the eight Bursaphelenchus species found, Bursaphelenchus abietinus and B. andrassyi were identified through morphological and molecular

Six species of the genus Bursaphelenchus were recovered as the result of a survey to assess the potential introduction of Bursaphelenchus xylophilus into the conifer forests of Romania. Bursaphelenchus xylophilus was not detected in the sampling regions. Bursaphelenchus dietrichi was recovered from one point, representing the first report of this species in the country. The other detected species,

Taxonomical re‐examination of the Phyllosticta species parasitic fungi on coniferous trees (Cupressaceae) in Japan was conducted based on current criteria, such as morphological and cultural characteristics, phylogenetic relationship and pathogenicity. Phylogenetic analyses revealed several clades composed of plant pathogens isolated from a specific host as well as clades composed of endophytic species

The genus Quambalaria includes several important pathogens of Eucalyptus and Corymbia spp., mainly those that cause leaf and shoot blight. The species Quambalaria eucalypti has been reported to be an aetiological agent of this disease in Brazil only in nurseries involved in the production of Eucalyptus minicuttings, where climatic conditions are more favourable for the pathogen. The aim of this study

In temperate systems of the Northern Hemisphere, wood‐decay fungi are known to facilitate cavity excavation by woodpeckers. For South America, woodpecker–fungi interactions have not been explored. The aim of this work was to identify wood‐decay fungi associated with the process of cavity excavation by the Magellanic woodpecker (Campephilus magellanicus), a large South American picid that excavates

A Belgium‐wide survey to determine the presence of ‘Candidatus Phytoplasma ulmi’ elm trees was performed on nearly 600 elm trees. The randomly sampled elms were screened for the presence of phytoplasmas using a standard generic nested PCR method. In five symptomless elm trees, phytoplasmas were detected. Multiple gene sequence analysis (16S rRNA, tuf, rplV‐rpsC‐rplP), virtual RFLP of the 16S rRNA gene

Most wood‐decay fungi contribute to the healthy functioning of forest ecosystems, whereas others cause infectious diseases of woody plants and high economic losses for forest management. In this study, we pursued the hypothesis that pathogenic wood‐rotting Agaricomycetes occur less frequently in undisturbed forests than in managed stands, especially artificial monocultures. The prevalence of two important

Spots have been observed on petioles and along the midrib and vein of leaves from saplings and shrubs of Erythrina variegata in a Brazilian municipality in the state of Minas Gerais. An acervular fungus resembling Colletotrichum spp. was consistently observed associated with these spots. The aim of this study was to identify the fungus associated with E. variegata employing morphological characteristics

Increased diseases outbreaks in Gmelina arborea (melina) are a threat to sustainability of commercial plantations. One main disease, known as 'melina sudden death', limits the growth and development of trees, causing losses of up to 40% in commercial plantation. However, the main cause of this disease was unknown, until now. Proof of Ceratocystis fimbriata as the aetiological agent of 'melina sudden

In March 2020, symptoms of powdery mildew were observed on Bauhinia variegata, B. blakeana and Desmodium caudatum in Taiwan. The fungus was identified as Erysiphe lespedezae based on morphological characteristics of the anamorph and the molecular analysis of the rDNA ITS sequences. In the phylogenetic tree, the powdery mildews on Bauhinia spp. and D. caudatum were divided into two groups, suggesting

During the monitoring of oak decline phenomenon in Slovakia, symptoms indicative of Phytophthora diseases were observed in sessile oak stands in western Slovakia. The study aimed to test the presence and diversity of Phytophthora species associated with declining oak stands. From rhizosphere soil samples, Phytophthora plurivora, P. quercina and Pythium intermedium were detected. Soil inoculation tests

The high economic return from sales of palm oil is because of its inclusion in a vast range of commodities, and Malaysia is the second largest producer after Indonesia. However, increasing cultivation of oil palm has a negative environmental impact threatening sustainability. Basal stem rot (BSR) by Ganoderma boninense is of major concern to sustainability of the palm oil industry. CLIMEX, a computer

Reports of Ailanthus altissima stand declines in south‐central Pennsylvania resulted in the identification of the causal agent, a vascular wilt fungus, Verticillium nonalfalfae. Additional surveys throughout North America and Europe found that this disease outbreak was not an isolated event. One of these surveys identified and monitored six naturally diseased A. altissima stands in Virginia, USA, between

Production of β‐glucosidase was investigated in nine isolates of Armillaria representing four species found in Europe: Armillaria mellea and Armillaria ostoyae, considered to be pathogenic and moderately pathogenic, respectively, and Armillaria. gallica and Armillaria cepistipes, both considered to be non‐pathogenic. β‐glucosidase was predominantly produced in the rhizomorphs, while the vegetative

The performance of laboratory X‐ray computed tomography (XCT) for the non‐destructive imaging of root wood was evaluated. Lateral roots of oriental cherry (Prunus serrulata var. spontanea) and Japanese zelkova (Zelkova serrata) were severed in spring and maintained in soil for 6 months. Without sectioning, XCT revealed the phloem, xylem and vascular cambium structures in the root wood. A virtual transverse

In February 2015, an unexpected windstorm downed five hectares of a European black pine Pinus nigra subsp. laricio forest formation located close to Vallombrosa, Florence (Central Italy). In the following spring, an extensive survey was conducted in the area. Felled trees, stumps and all the suitable plant material were screened for the presence of the pinewood nematode (PWN), Bursaphelenchus xylophilus

Trees of Cenostigma tocantinum showing brown leaf spots surrounded by chlorotic areas were observed at the campus of the Federal University of Amazonas, Brazil, in 2018. Necrotic lesions were covered by orange masses of hyaline cylindrical conidia with rounded ends, typical of the genus Colletotrichum. Three monoconidial isolates were subject of DNA extraction followed by PCR amplification and sequencing

Erysiphe bulbouncinula (≡ Bulbouncinula bulbosa) on Koelreuteria paniculata is a powdery mildew native and endemic in China. Fresh samples of this species were collected on K. paniculata in Sichuan Province, China, in 2018. This is the fourth confirmed identification of this species. The original description in 1932 was based on one specimen from Hangzhou and then was described in Nanjing in 1990 and

In September 2019, two diseased plants of Campsis grandiflora showing the main symptom of witches' ‐broom (CgWB) were found in a nursery garden in Yangling, Shaanxi province, China. Partial 16S ribosomal RNA (F2nR2 region) and ribosomal protein (rp) genes of phytoplasmas were generated from the symptomatic plants by PCR amplification, and phytoplasma bodies were observed in the sieve tube elements

Ceratocystis platani causes canker stain of plane trees, and it represents a serious disease of Platanus spp. both in the United States and Europe. Current chemical or biological controls do not effectively manage C. platani, so new preventive methods need to be developed in order to limit this pathogen spreading. In this work, we have characterized the main volatile organic compounds (VOC) emitted

The genus Ganoderma Karst. has broad‐spectrum usage in biotechnology, medicine and the food industry. The complexity of the morphology within species has led to uncertain identification in the past, but recent advancements in molecular identification methods have provided scientists with the opportunity to better understand the taxonomy of the species. The present study attempts for the first time

Oil palm (OP) is affected by climate change and the cultivation of the crop also contributes to climate alteration. Simulation modelling and large data sets indicated the effects of climate change on OP will be to (a) reduce growth and yields and (b) cause death of some OP. Furthermore, basal stem rot (BSR) caused by Ganoderma boninense, a serious disease of OP, has increased over the past two or three

Sweet crab apple (Malus coronaria) is a popular ornamental tree planted in gardens and urban forests in South Korea. In 2018, severe symptoms were observed on street plantings of sweet crab apple in Jinju, South Korea including shoot blight: shoot tips, twigs and foliage of infected trees turned brown, and dried completely. The causal agent isolated from the disease lesions was identified as Pseudomonas

A foliar nematode, Litylenchus crenatae ssp. mccannii, is associated with beech leaf disease (BLD) symptoms. Information about the types of tissues parasitized and how nematode populations fluctuate in these tissues over time is needed to improve surveys as well as understand the nematodes role in BLD. During this study, the nematode was detected throughout the known range of BLD by researchers at

Phytophthora austrocedri is a recently invasive soilborne pathogen which is causing widespread mortality of Juniperus communis in northern Britain. The pathways by which a single genotype of P. austrocedri has spread to infect such a geographically dispersed range of woodland sites within a relatively short timeframe are unknown. This study examined the detectability of P. austrocedri in soil and water

The pine wood nematode (PWN), Bursaphelenchus xylophilus, causes huge economic losses in pine forests. The plant‐parasitic nematodes have a complex life cycle that includes the secretion of effector proteins through a stylet into the host cell to promote parasitism. In this study, SignalP 4.1 and TMHMM 2.0 were used in preliminary screens for candidate effectors and were expressed in Nicotiana benthamiana

During 2017, Dutch elm disease was investigated on 67 Ulmus glabra and 29 Ulmus laevis samples from 28 sites in Latvia. The presence of Ophiostoma novo‐ulmi was detected in 61.2% of the samples from U. glabra and in 34.5% of the samples from U. laevis. In 11% of cases, hybrids between subsp. novo‐ulmi and subsp. americana were identified, particularly in the sites in the southern part of Latvia. This

Florida torreya (Torreya taxifolia Arn.) is an endangered conifer with a very limited range in the USA: two counties in Florida and one in Georgia, along the Apalachicola River. The species was once abundant in its small native range but suffered a major decline, ~99% loss, in the late 1950s to early 1960s that is thought to have been caused by a disease. Recently, a canker disease caused by Fusarium

Plant lesions affect disease impact, progression and host resistance. Root lesions caused by Armillaria ostoyae (Romagn.) Herink were inspected on 24‐ to 34‐year‐old planted Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) pulled from the soil in five locations. Four hundred seventy‐nine lesions were measured for length (mm), expansion rate (mm/year) and lesion type. Lesion types were patch lesions

In 2015–2016, damping‐off symptoms were observed on Pinus sylvestris and Picea abies seedlings in four forest nurseries in Poland. Some Calonectria isolates were obtained from symptomatic seedlings by culturing pieces of necrotic tissue on malt extract agar.Morphological and molecular analyses revealed that isolates represent Calonectria montana, a recently described species from natural forests in

Since 2015, Araucaria araucana, an ecologically and economically important conifer native to Argentina and Chile, has suffered an unusual partial death of the crown throughout almost all of the distribution range in Argentina. No primary pathogen or pest was evident, associated with the phenomenon. Isolates of Mortierella, a poorly studied fungal genus in Patagonia, were obtained from the margins of