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Sandy soils are widespread globally and are increasingly utilized to meet the demands of a growing population and urbanization for food, fiber, energy, and other essential services. However, their poor water and nutrient retention makes crop cultivation challenging. This study evaluated the effects of integrating compost and plant growth-promoting rhizobacteria (PGPR; Azospirillum brasilense SWERI 111 and Azotobacter chroococcum OR512393) on wheat (Triticum aestivum L. var. Misr 1) grown in sandy soil under varying levels of recommended NPK (50%, 75%, and 100%) fertilization. Conducted over two growing seasons, the experiment aimed to assess soil health, nutrient uptake, microbial activity, and plant productivity in response to compost and PGPR treatments. The results demonstrated that combining compost and PGPR significantly improved soil chemical properties, such as reducing soil pH, electrical conductivity (ECe), and sodium adsorption ratio (SAR), while enhancing soil organic matter (SOM). Additionally, compost and PGPR improved soil nutrient content (N, P, K) and boosted the total bacterial and fungal counts. The combined treatment also increased urease and phosphatase enzyme activities, contributing to enhanced nutrient availability. Notably, plant productivity was enhanced with compost and PGPR, reflected by increased chlorophyll and reduced proline content, along with improved grain and straw yields. Overall, the results underscore the potential of compost and PGPR as effective, sustainable soil amendments to support wheat growth under varying NPK levels. [ABSTRACT FROM AUTHOR]

THE SUPPRESSION effect of four biocontrol agents (i.e., cyanobacteria extracts: Nostoc linckia, Anabaena variabilis, Oscillatoria agardhii, and Spirulina sp.), in combination with Rhizobium leguminosarum biovar viceae (TAL–1148), against Rhizoctonia solani in faba bean plants was investigated through laboratory and pot experiments. After testing five R. solani isolates for pathogenicity, all of the identified fungi were found to be pathogenic and to have induced symptoms of root rot and pre- and post-damping-off. Comparing the results of in vitro experiments to the untreated control, algal extracts dramatically suppressed the pathogen's ability to develop mycelially. In comparison to the control (0%), O. agardhii showed the highest reduction (59.63%), followed by N. linckia (51.85%), A. variabilis (48.52%), and Spirulina sp. (40.37%). When compared to the other studied cyanobacteria and the control treatment, the combined effect of Rhizobium and cyanobacteria extracts (O. agardhii and N. linckia) produced the highest reduction in pre- and post-emergence damping-off, measuring 13.33 and 6.67%, respectively, in pot studies. Furthermore, in comparison to the control, these treatments enhanced the number and dry weight of nodules, shoot height, dry weight of shoots, N2%, and N content. Similar results were obtained using the fungicide Rizolex-T50%, which decreased the incidence and severity of the disease but had negative effects on Rhizobium and the symbiotic N2–fixing characteristics. Plants cultivated from treated faba bean seeds showed notable increases in the activity of the oxidative reductive enzymes (i.e., peroxidase and polyphenol oxidase). Thus, it could be concluded that using algal extracts in conjunction with R. leguminosarum was thought to be a practical, secure, and economical way to manage this type of soil-borne disease. More further studies are needed to emphasize this sustainable and eco-friendly approach using different phytopathogens. [ABSTRACT FROM AUTHOR]

Fusarium solani is one of the most common pathogens, causing damping-off disease of faba bean (Vicia fabe L.) in Egypt. Four obtained isolates were able to attack faba bean plants (cv. Sakha1) causing damping-off disease. Isolate 2 (identified as F. solani) was the most virulent one in the pathogenicity test. The antagonistic effect of three Trichoderma species, i.e. T. harzianum, T. hamatum, and T. virens was tested in vitro against F. solani and in greenhouse experiments. In vitro, all Trichoderma spp., significantly reduced the mycelial growth of F. solani and showed a mycoparasitic activity against the pathogenic fungus. In greenhouse experiments, combined effect of Trichoderma spp. (as seed or soil treatments) and Rhizobium leguminosarum bv. viceae significantly reduced the pre-and post-emergence damping-off disease incidence under artificial infection with F. solani. The best protection was obtained by soil treatment of T. virens, followed by T. harzianum and T. hamatum, respectively. The treatments gave highest plant survival (%) values and improved the growth parameters, symbiotic N2 fixing and yield components, compared with infected control. The effects were similar in more cases to those of applying the fungicide Rizolex-T50%, which reduced the damping-off disease incidence but adversely affected Rhizobium sp. and the symbiotic N2 fixing parameters. Sensitivity of the Rhizobium and Trichoderma strains to some chemical pesticides (Rhizolex-T50, ground-up, malathion and Rugby) was tested. All tested fungicides showed toxic effects to Rhizobium and Trichoderma strains, even at low concentrations. The fungicide Rizolex-T50% was the most effective one even at the one forth recommended dose. [ABSTRACT FROM AUTHOR]

Powdery and downy mildews are potentially serious diseases of cucumber inflicting considerable quantitative and qualitative losses. Efficacy of Bacillus subtilis, Pseudomonas fluorescens, Derxia gummosa and Trichoderma harzianum to control both diseases on cucumber plants under greenhouse conditions was studied. Spray of cucumber plants with suspensions of these bioagents significantly reduced severity of both mildews as well as increased fruit yield (Kg/plant) compared to the control. B. subtilis recorded highest reduction of area under disease progress curve (AUDPC), being 175.0 as compared to 536.55 in the control for powdery mildew, while T. harzianum recorded highest reduction being 241.15 as compared to the control (513.45) for downy mildew. Light and scanning electron microscopy showed that Podosphaera fusca and Pseudoperonospora cubensis spores and hyphae were abnormal and both pathogens had restricted growth on treated-cucumber plants. Additionally, treated plants showed significant increase in plant growth parameters (plant height, total chlorophyll and fresh and dry weight) and the activity of defense related enzymes (peroxidase and polyphenoloxidase) compared to the untreated plants. The results suggest the possible use of B. subtilis, T. harzianum and P. fluorescens to control powdery and downy mildews on cucumber. [ABSTRACT FROM AUTHOR]