Empirical models for predicting the production of wild mushrooms in Scots pine (Pinus sylvestris L.) forests in the Central Pyrenees

Mushroom picking has become a widespread autumn recreational activity in the Central Pyrenees and other regions of Spain. Predictive models that relate mushroom production or fungal species richness with forest stand and site characteristics are not available. This study used mushroom production data from 24 Scots pine plots over 3 years to develop a predictive model that could facilitate forest management decisions when comparing silvicultural options in terms of mushroom production. Mixed modelling was used to model the dependence of mushroom production on stand and site factors. The results showed that productions were greatest when stand basal area was approximately 20 m2 ha-1. Increasing elevation and northern aspect increased total mushroom production as well as the production of edible and marketed mushrooms. Increasing slope decreased productions. Marketed Lactarius spp., the most important group collected in the region, showed similar relationships. The annual variation in mushroom production correlated with autumn rainfall. Mushroom species richness was highest when the total production was highest.La cueillette de champignons est devenue une activité de loisir très répandue dans les Pyrénées centrales ainsi que dans d'autres régions d'Espagne. Aucun modèle prédictif de production ou de richesse en espèces en fonction des caractéristiques des peuplements et des stations n'est disponible actuellement. La présente étude s'est basée sur des données de récolte de champignons de 24 placettes de pin sylvestre suivies pendant 3 ans pour développer un modèle prédictif pouvant servir de modèle d'aide à la décision pour des opérations de gestion forestière. Un modèle mixte a été mis en oeuvre pour analyser les relations entre facteurs stationnels et de peuplement. Les résultats montrent que la production était maximale quand la surface terrière était de l'ordre de 20 m2 ha-1. La production totale ainsi que celle de champignons comestibles et commercialisables augmentaient avec l'altitude et dans les pentes orientées au nord. Le groupe des Lactaires (Lactarius spp.) le plus important champignon commercialisable de la région, présentait des réponses similaires. La variabilité interannuelle de production était étroitement corrélée à celle des pluies automnales. La richesse en espèce était étroitement corrélée à la production totale

Cultivation of black truffle to promote reforestation and land-use stability

Cultivation of black truffle, Tuber melanosporum Vitt., has become an important agricultural alternative in rural Mediterranean regions due to its success in relatively harsh conditions, its high market value and diminishing production in natural areas. In addition, truffle cultivation requires relatively low agricultural inputs, promotes reforestation and economic restoration of rural lands and land-use stability. However, there remain major issues regarding the management practices to ensure successful black truffle production. We therefore conducted an experiment to evaluate 3 levels of irrigation based on monthly water deficit and the effects of currently applied weed control systems and fertilization. Treatment effects were evaluated by examining the mycorrhizal status of out-planted 1-yr-old Quercus ilex L. seedlings and seedling growth parameters after 18 months in 3 distinct experimental truffle plantations located in the foothills of the Spanish Pyrenees. We found that replacing one-half of the water deficit of the driest month (moderate irrigation) promoted the proliferation of T. melanosporum mycorrhizae, while high irrigation reduced fine root production and truffle mycorrhizae. Glyphosate weed control improved seedling survival by up to 16% over control seedlings without jeopardizing truffle mycorrhizae in the first year. Fertilization did not improve seedling growth or influence its mycorrhizal status. We describe the persistent relationship between this ectomycorrhizal fungus and Q. ilex by quantifying old and new mycorrhizae and we discuss the ecological implications of the symbiosis

New qPCR protocol to detect Diplodia corticola shows phoretic association with the oak pinhole borer Platypus cylindrus

BACKGROUND: Botryosphaeria canker (causal agent: Diplodia corticola) is considered one of the most important diseases of cork oak (Quercus suber) stands since it necrotizes the subero-phellodermic layer preventing cork regeneration after harvesting. One of the most intriguing etiological issues of this disease is its plausible spreading through trunk borer insects. In this study, we highlight the phoretic relationship between D. corticola and the oak pinhole borer Platypus cylindrus (Coleoptera, Curculionidae) which massively colonizes debarked cork oaks in southern Europe. We extracted DNA from 154 adults of P. cylindrus collected in six cork oak stands in north-eastern Spain during the summer of 2021. We developed a new nested quantitative PCR-based protocol for quick detection of D. corticola carried by insects. RESULTS: The use of real time amplification of a highly specific mitochondrial marker allowed us to detect spore loads down to a single conidium within the first 29 cycles of qPCR. The 29.62% of insect pools (corresponding to 31.16% of studied insects) resulted in an estimated spore load higher than one conidium/insect, with a moderate value of mean spore load for the whole dataset (~33 conidia/insect). Estimated spore load was significantly higher in May and August, regardless of insect abundance in the field. CONCLUSION: This study provides new tools for diagnosis of this emergent pathogen that would be useful for developing monitoring strategies and epidemiological studies

Antagonistic effect in vitro of three commercial strains of Bacillus sp. against the forest pathogen Diplodia corticola

Botryosphaeria canker of Quercus suber (causal agent: Diplodia corticola) poses a major threat for cork production along the western Mediterranean Basin. Infection by D. corticola induces cankers, which reduce tree vigour and compromise phellem regeneration. European policies in forest health advise the use of environmentally friendly methods, such as biocontrol, rather than the use of chemicals in natural stands. In this study, we assessed the antagonistic potential of three commercial products involving bacteria (Bacillus amyloliquefaciens and Bacillus mojavensis) using two culture media [potato-dextrose-agar medium (PDA), and PDA amended with copper oxychloride, an inorganic fungicide] against D. corticola. Five indices based on colony dimensions showed significant antagonistic effects of bacteria on fungal growth in vitro. The copper salt showed high toxicity against D. corticola. Preliminary results suggest that the three commercial products might be used as biocontrol agents against D. corticola, whose control capacities in the field deserve further investigation