Endophytic fungi (EF) can enhance both plant growth and defense barriers against pests and pathogens, contributing to the reduction of chemical pesticides and fertilizers use in agriculture. Beauveria bassiana is an entomopathogenic fungus showing endophytism in several crops, often associated with a good capacity to limit the development of pests and disease agents. However, the diversity of the protective efficacy and plant response to different strains can be remarkable and needs to be carefully assessed for the successful and predictable use of these beneficial microorganisms. This study aims to select B. bassiana strains able to colonize tomato plants as endophytes as well as to control two important disease agents, Botrytis cinerea and Alternaria alternata, and the pest aphid, Macrosiphum euphorbiae. Nine wild-type isolates and one commercial strain were screened for endophytism, then further characterized for plant-growth promotion plus inhibition of disease development and pest infestation. Four isolates proved to have a good control activity against the biotic stressors tested, but only Bb716 was also able to promote plant growth. This work provides a simple workflow for the selection of beneficial EF, paving the way towards more effective use of B. bassiana in Integrate Pest Management (IPM) of tomato.

Soilborne pathogens and pests in agroecosystems are serious problems that limit crop yields. In line with the development of more ecologically sustainable agriculture, the possibility of using biochar to control pests has been increasingly investigated in recent years. This work provides a general overview of disease and pest suppression using biochar. We present an updated view of the literature from 2015 to 2022 based on 61 articles, including 117 experimental case studies. We evaluated how different biochar production feedstocks, pyrolysis temperatures, application rates, and the pathosystems studied affected disease and pest incidence. Fungal pathogens accounted for 55% of the case studies, followed by bacteria (15%), insects and nematodes (8%), oomycetes and viruses (6%), and only 2% parasitic plants. The most commonly studied belowground pathogen species were Fusarium oxysporum f. sp. radicis lycopersici in fungi, Ralstonia solanacearum in bacteria, and Phytophthora capisci in oomycetes, while the most commonly studied pest species were Meloidogyne incognita in nematodes, Epitrix fuscula in insects, and both Phelipanche aegyptiaca and Orobanche crenata in parasitic plants. Biochar showed suppression efficiencies of 86% for fungi, 100% for oomycetes, 100% for viruses, 96% for bacteria, and 50% for nematodes. Biochar was able to potentially control 20 fungal, 8 bacterial, and 2 viral plant pathogens covered by our review. Most studies used an application rate between 1% and 3%, a pyrolysis temperature between 500 °C and 600 °C, and a feedstock based on sawdust and wood waste. Several mechanisms have been proposed to explain disease suppression by biochar, including induction of systemic resistance, enhancement of rhizosphere competence of the microbial community, and sorption of phytotoxic compounds of plant and/or microbial origin. Overall, it is important to standardize biochar feedstock and the rate of application to improve the beneficial effects on plants in terms of disease control.

Wood vinegar is a by-product of the pyrolysis of organic raw materials. In this study, we investigated the chemical composition and biological activity of industrial wood vinegar derived from the pyrolysis of wood pruning waste. The composition of wood vinegar was characterized using liquid chromatography (LC) and gas chromatography–mass spectrometry (GC-MS). Wood vinegar bioactivity was tested against Bactrocera oleae under field conditions in an olive grove for two years. Furthermore, wood vinegar was applied in a greenhouse experiment with strawberry plants and in a strawberry field infested with the nematode Meloidogyne incognita. Finally, a seed root length bioassay was performed to evaluate the phytotoxicity or biostimulation of wood vinegar on Eruca sativa, Lactuca sativa, Lens culinaryis, Lolium multiflorum, and Solanum lycopersicum. Our results showed that wood vinegar had a pH of 3.2, with high concentrations of acetic acid (27,840.16 mg L⁻¹) and phenols (54.00 mg L⁻¹). No repellent effect against B. oleae was observed when wood vinegar was applied as an aerosol in olive groves. On strawberry plants in greenhouse conditions, wood vinegar showed phytotoxic effects at high concentrations, resulting in a decrease in the total yield of the plants. In the field, at a 1% concentration, wood vinegar led to a significant 15% reduction in the infection caused by M. incognita in strawberry plants. Finally, in the in vitro crop bioassay, wood vinegar demonstrated remarkable phytotoxicity effects at high concentrations while promoting root growth when diluted. The efficacy of wood vinegar displayed considerable variability based on concentration and delivery system, emphasizing the need for careful evaluation when considering its application, particularly in diverse crops and production systems.

The aim of this work was to compare the application of biochar, compost, and their mixtures on soil fertility and crop yields using a volcanic Mediterranean soil. For this reason, three types of organic amendments (OAs) were selected: compost1, made from olive mill waste and orchard pruning residues; compost2, made from olive mill waste, animal manure and wool residues; and biochar made from beech wood pyrolyzed at 550 °C. When selected, the OAs were characterized chemically for organic carbon (OC), total N, pH, electric conductivity (EC) and the bulk fraction of organic matter using ¹³C CPMAS NMR spectroscopy. In addition, soil chemistry was analysed at the end of each year for the following parameters: pH, OC, total N, CaCO₃, P₂O₅, NH₄, FDA and EC. Results showed that biochar had the highest OC and the lowest N and EC compared to both composts. Moreover, ¹³C CPMAS NMR showed that biochar had the lowest content of O-alkyl, methoxyl- and alkyl-C and the highest content of aromatic-C. On the other hand, compost2 and compost2+biochar mixture reduced Aubergine yield by −60% and −40%, respectively, and tomato yield by −50% and −100%, respectively. Nevertheless, a significant increase in onion and rape yields were observed when compost1, compost1+biochar and compost2 were applied, while biochar and compost2+biochar significantly decreased the yield of these crops. Overall, our results highlight that the effect of OAs on crops yield is largely variable and influenced by the interaction with soil chemistry.

Peat has long been the primary substrate for the production of ornamental and horticultural plants in pots. Today, peat is no longer considered a renewable resource due to its very lengthy regeneration time. Biochar, a solid by-product of biomass pyrolysis, has been proposed as an agricultural soil amendment. We investigated the effects of two types of biochar, namely biochar from pruning wood waste and biochar activated with wood vinegar (“smoked biochar”), on two ornamental plants (Lavandula angustifolia and Salvia rosmarinus) and on strawberries (Fragaria × ananassa). For both types of biochar, we measured the following parameters: the pH, density, electrical conductivity, humidity, calcium carbonate, total carbon, nitrogen, potassium, calcium, magnesium, sodium, and water retention. For peat, we measured the following parameters: the pH, electrical conductivity, total carbon, and total nitrogen. Our results showed an overall increase in plant growth, particularly in L. angustifolia when using 10% and 50% biochar concentrations and a 10% concentration of biochar activated with wood vinegar. In S. rosmarinus, we observed a slight increase in the total plant weight with the application of 10% smoked biochar (biochar activated with wood vinegar). Finally, in F. × ananassa, we observed an increase in the plant weight and fruit production when 10% biochar was applied. On the other hand, when high concentrations of biochar (50% and 100%) and especially smoked biochar were applied, we observed a significant reduction in the growth of all plants. We concluded that biochar and biochar activated with wood vinegar showed remarkable biological activity with marked phytotoxicity at high concentrations. They promoted plant growth when applied diluted and their use as partial peat substitutes could help support more sustainable horticultural practices.