Global Geographic Distribution and Host Range of Fusarium circinatum, the Causal Agent of Pine Pitch Canker

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 global distribution of F. circinatum is poorly documented, and this problem is also true of the hosts within countries that are affected. The aim of this study was to review the global distribution of F. circinatum, with a particular focus on Europe. We considered (1) the current and historical pathogen records, both positive and negative, based on confirmed reports from Europe and globally; (2) the genetic diversity and population structure of the pathogen; (3) the current distribution of PPC in Europe, comparing published models of predicted disease distribution; and (4) host susceptibility by reviewing literature and generating a comprehensive list of known hosts for the fungus. These data were collated from 41 countries and used to compile a specially constructed geo-database. A review of 6297 observation records showed that F. circinatum and the symptoms it causes on conifers occurred in 14 countries, including four in Europe, and is absent in 28 countries. Field observations and experimental data from 138 host species revealed 106 susceptible host species including 85 Pinus species, 6 non-pine tree species and 15 grass and herb species. Our data confirm that susceptibility to F. circinatum varies between different host species, tree ages and environmental characteristics. Knowledge on the geographic distribution, host range and the relative susceptibility of different hosts is essential for disease management, mitigation and containment strategies. The findings reported in this review will support countries that are currently free of F. circinatum in implementing effective procedures and restrictions and prevent further spread of the pathogen

Sampling and Detection Strategies for the Pine Pitch Canker (PPC) Disease Pathogen Fusarium circinatum in Europe

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 considers the probability of new introductions—via contaminated seeds, wood material, soil and growing substrates, natural means and human activities—into the EU very likely. Due to early detection, constant surveillance and control measures, F. circinatum outbreaks have officially been eradicated in Italy and France. However, the global spread of F. circinatum suggests that the pathogen will continue to be encountered in new environments in the future. Therefore, continuous surveillance of reproductive material, nurseries and plantations, prompt control measures and realistic contingency plans will be important in Europe and elsewhere to limit disease spread and the “bridgehead effect”, where new introductions of a tree pathogen become increasingly likely as new environments are invaded, must be considered. Therefore, survey programs already implemented to limit the spread in Europe and that could be helpful for other EU countries are summarized in this review. These surveys include not only countries where pitch canker is present, such as Portugal and Spain, but also several other EU countries where F. circinatum is not present. Sampling protocols for seeds, seedlings, twigs, branches, shoots, soil samples, spore traps and insects from different studies are collated and compiled in this review. Likewise, methodology for morphological and molecular identification is herein presented. These include conventional PCR with a target-specific region located in the intergenic spacer region, as well as several real-time PCR protocols, with different levels of specificity and sensitivity. Finally, the global situation and future perspectives are addressed

Causes of oak stand decline

Agents causing damage to plant organisms like drought, folivore feeding, fungal pathogens, ground frosts have no significant effect on tree mortality if they occur individually, however their concurrent occurrence may lead to mass dieback of trees on a local scale. Changes in cell biochemistry of trees under the impact of stress factors enable development of fungal infections or facilitate insect attacks. This study presents examples of interactions between physiological changes (e.g. in production of enzymes, phenolic compounds, etc.) determining host plant resistance and pathogen or pest responses to these changes

The usefulness of traps and PDA medium for Phytophthora alni isolation from infected tissues and soil

The purpose of the study was to determine the usefulness of green apples as well as leaves of rhododendron as trapping methods for isolation of Phytophthora alni in disease tissues and in the soil. Apple traps as well as rhododendron leaves may be used successfully for isolation of the pathogen from roots, stem collar and from the soil, respectively. Such baits are particularly recommended for pathogen isolation from mature trees what is usually more difficult than in the case of seedlings. Apart of P. alni, faster growing of Fusarium, Botrytis, Cladosporium, Chaetomium and Trichoderma species on PDA medium were also isolated from the base of stems of diseased alders. It could be also the reason why P. alni was not always isolated from diseased tissues

Zagrożenie szkółek i drzewostanów, ze szczególnym uwzględnieniem olszy przez gatunki z rodzaju Phytophthora

Many pathogenes of Phytophthora genera (P. cactorum, P. citricola, P. cinnamomi and P. citrophthora) are present in the forest and ornamental nurseries all over the Europe. They cause serious disease of many of forest tree species (f.ex. alder, oak and beech). Infected seedlings in nurseries when planted along river plantations are the main source of infection which spread further down of the stream. More research about this phenomen is needed in Poland

Slow Sand Filter as a method of protection forest plants against phytopathogens in forest nurseries

Slow sand filtration (SSF) is a low−cost method of water disinfestation that can be used as an alternative method of water irrigation treatment in nursery to control water−borne phytopathogens. Slow sand filtration relies on physical, chemical and biological activity in controlling plant pathogens. In a SSF, the filter bed is constructed of a medium−sand with the area which can be colonised by microorganisms – biofilm. This sand media also presents a physical barrier to fungal, bacterial and oomycetes plant pathogens. In the forest nursery Kiejsze an experimental slow sand filter was constructed to study the structure of a bacterial community suppressive to plant pathogens. The total bacterial community of an experimental SSF was analyzed by denaturing gradient gel electrophoresis (DGGE) of partial 16S rRNA gene PCR products. Sequence analysis of DGGE bands from the SSF column indicated that a range of bacteria were present, among them similar to groups such as alfa−Proteobacteria, delta−Proteobacteria, beta−Proteobacteria, Planctomycetes, Actinobacteria, Firmicutes, Bacilli and an uncharacterized environmental clone. This study describes the characterization of the microbial community of SSFs used for the treatment of irrigation water in the forest nursery. Using of natural SSF filters and manipulation of microorganisms in the biofilm may be a more reproducible control method of plant pathogens in the future