More than 10 million metric tons of spent mushroom compost (SMC), which is a by-product of Agaricus bisporus mushroom, is produced in the world. Adding the compost to the soil resulted in improving the nutritional status of the plants. This study aims experiment is to study the effect of SMC on cucumber plant growth. A basic property of SMC and high concentrations of soluble salts restricted its implementation in the agricultural arena. The SMC was leached in order to reduce its salinity. Leached spent mushroom compost has less salinity while carbon and nitrogen content as well as inorganic cation components did not change significantly when compared to non-leached SMC. To study the effects of SMC on plant growth, leached SMC in rates of 15, 25, 35, and 45% were added to a sandy-loam soil medium. Cucumber plant growth rate was evaluated based on fruit number and plant height. Results showed that additions of 15% and 25% leached SMC to growing media significantly improved the cucumber plants growth.

Crop diseases and agricultural pests and pathogens are causing huge economic losses. The actual means for dealing with them involve the use of damaging chemical pesticides that harm the environment, threaten biodiversity, and undermine human health. This research was aimed at developing an environmentally friendly means to cope with emerging oomycete disease from tomato fields in the province of East-Azerbaijan. The oomycete disease causal agent was isolated and identified as Ovatisporangium sp. using a combination of morphological features and molecular methods. Six wood vinegars (pyroligneous acid) belonging to pine, pomegranate, pistachio, almond, walnut, and cypress were produced during this study and examined against Ovatisporangium sp. Their inhibition of volatile metabolites (VOCs) using different dilutions (1, 1/2, 1/4, 1/8, and 1/10) was assessed against the mycelial growth of Ovatisporangium sp. In vitro analysis demonstrated that pistachio, cypress, and almond dilution 1 (D 1) wood vinegar VOCs had the ability to stop the mycelial growth of Ovatisporangium sp. All other treatments including pine, walnut, and pomegranate with relevant dilutions significantly reduced the mycelial growth of Ovatisporangium sp. compared with the control (p ≤ 0.05). Wood vinegar is therefore a potent means to cope with pathogenic infections and allows plant protection against oomycete diseases.

Plant disease outbreaks are increasingly exacerbated by climate change and the conditions of stress combinations. They are negatively affecting crop yield and driving threats to food security in many areas of the world. Although synthetic pesticides offer relative success in the control of pests and plant diseases, they are often overused, and this method faces numerous drawbacks, including environmental toxicity, soil degradation, and adverse effects on human health. Therefore, alternatives are being developed and examined, including the biocontrol of pests and pathogens and biomass pyrolysis leading to wood vinegar that has shown great promise in agriculture and organic farming. However, while wood vinegar use is expanding and allows the control of numerous pests and bacterial and fungal diseases, its application to control oomycete diseases is limited. This study aimed to test wood vinegar for the control of oomycete plant pathogens from which six wood vinegars of pistachio, pomegranate, almond, pine, cypress, and walnut were produced. The inhibitory effects of volatile metabolites (semi-VOCs) of different wood vinegars concentrations (100%, 50%, 25%, 12.5%, and 6.25%) were examined against the hyphal growth of Globisporangium ultimum and Pythium aphanidermatum isolates. An in vitro analysis unambiguously demonstrated that for Globisporangium ultimum, the wood vinegar semi-VOCs of almond, pistachio (C 100% and 50%), and walnut (C 100%) totally inhibited mycelial growth. On the other hand, Pythium aphanidermatum, pistachio (C 100%, 50%, and 25%), and cypress (C 100%) expressed their abilities to completely inhibit the mycelial growth. Other treatments, including relevant concentrations of pine and pomegranate significantly inhibited the growth of mycelia of both species compared to the control (p ≤ 0.05). Therefore, wood vinegar could be considered a natural and organic product to use in agriculture to cope not only against pests, bacterial and fungal pests but also against emerging oomycete plant diseases.

Leached spent mushroom compost (SMC) and its extract were tested to suppress Lecanicillium fungicola in white button mushroom. Sterile and non-sterile mixture of SMC and peat were used to assess suppressiveness against L. fungicola in greenhouse experiments. The extract of SMC was prepared with sterile, non-sterile, filtered, supplied with nystatin, streptomycin and penicillin antibiotics to evaluate their effect in suppression of pathogen in vitro. Isolated bacteria from SMC extract were tested for antagonism rate against Lecanicillium fungicola. The results of the experiments showed that all applications rate of none-sterile SMC were effective in control of pathogen. However, the sterile SMC amendments did not have a positive effect on the pathogen suppression in vitro or in vivo, as was expected. The treatments amended with SMC 100% and 60% showed the most suppressive effect in the control of pathogen. Using of non-sterile SMC 20%, 40%, 60% and peat soil were most effective in mushroom yield. The extract of leached SMC showed inhibition of L. fungicola in petri dishes. Three bacteria isolated from extract, Bacillus subtilis, Bacillus licheniformis and Bacillus amyloliquefacien identified using 16s rRNA, showed an antagonistic effect with the fungal growth.