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In the current study, evaluation the ability of three isolates of Sclerotium rolfsii isolated from tomato, bean and cabbage to infect their host plants and two non-host plants was carried out. Tomato plants were strongly affected with the three isolates of the pathogen followed by cabbage plants, whereas common bean plants were the least in this respect. Six species of Trichoderma were examined for their bio-control potentials against S. rolfsii the causative of root rot in tomato, common bean and cabbage. In vitro antagonistic test showed that T. koningii exhibited high inhibitory effect as the percentage of inhibition value was higher in case of S. rolfsii (tomato isolate) followed by T. harzianum with S. rolfsii (bean isolate) and S. rolfsii (cabbage isolate). Under greenhouse conditions; T. koningii, T. viride and T. harzianum showed the highest antagonistic effect against the three isolates of S. rolfsii in pots experiment. Microscopic examinations showed that most of Trichoderma spp. grew over mycelia of the tested pathogen with surrounded, coiling, lysis of hyphae and collapse of mycelium. T. koningii and T. viride exhibited the best performance regarding to the defense enzyme secretion; chitinase and β-glucanase followed by T. harzianum. Also, all the tested Trichoderma spp. produced Indole acetic acid (IAA) and Gibberellic acid (GA) as a plant growth promoting substances in variable values.

Metal oxide nanoparticles have recently garnered interest as potentially valuable substances for the management of plant diseases. Copper oxide nanoparticles (Cu2ONPs) were chemically fabricated to control root rot disease in cucumbers. A scanning electron microscope (SEM), X-ray diffraction (XRD) and photoluminescence (PL) were employed to characterize the produced nanoparticles. Moreover, the direct antifungal activity of Cu2ONPs against Fusarium solani under laboratory, greenhouse, and field conditions were also evaluated. In addition, the induction of host-plant resistance by Cu2ONPs was confirmed by the results of enzyme activities (catalase, peroxidase, and polyphenoloxidase) and gene expression (PR-1 and LOX-1). Finally, the effect of Cu2ONPs on the growth and productivity characteristics of the treated cucumber plants was investigated. The average particle size from all the peaks was found to be around 25.54 and 25.83 nm for 0.30 and 0.35 Cu2O, respectively. Under laboratory conditions, the study found that Cu2ONPs had a greater inhibitory effect on the growth of Fusarium solani than the untreated control. Cu2ONP treatment considerably reduced the disease incidence of the root rot pathogen in cucumber plants in both greenhouse and field environments. Defense enzyme activity and defense genes (PR1 and LOX1) transcription levels were higher in cucumber plants treated with Cu2ONPs and fungicide than in the untreated control. SEM analysis revealed irregularities, changes, twisting, and plasmolysis in the mycelia, as well as spore shrinking and collapsing in F. solani treated with Cu2ONPs, compared to the untreated control. The anatomical analysis revealed that cucumber plants treated with Cu2ONPs had thicker cell walls, root cortex, and mesophyll tissue (MT) than untreated plants. Cucumber growth and yield characteristics were greatly improved after treatment with Cu2ONPs and fungicide. To the best of our knowledge, employing Cu2ONPs to treat cucumber rot root disease is a novel strategy that has not yet been reported.

Wheat stem rust causes by Puccinia graminis f. sp. tritici is a serious threat to wheat production all over the world. This study evaluated the efficacy of Bacillus subtilis, B. polymyxa and B. megaterium, Eugenol and leaf extract of Artemisia cina against the disease, and the involved mechanisms in disease resistance. B. subtilis and Eugenol treatments inhibited spore germination and increased incubation and latent periods than other treatments. Additionally, the lowest infection type, pustule length and pustule width, and receptivity (no. of pustules) were recorded in case of B. subtilis and Eugenol treatments compared with the check control. The best results in disease assessment were achieved by foliar spray application 24 h before and after inoculation. Abnormalities, lysis, collapse, and shrinking of urediniospores were recorded in treated leaves. The activities of antioxidant defense enzymes, i.e., catalase (CAT), peroxidase (POX), and polyphenoloxidase (PPO), were significantly increased in B. subtilis and Eugenol treatments. On the other hand, electrolyte leakage was decreased. The active compounds in B. subtilis were revealed by utilizing GC-MS analysis.

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ate blight caused by Phytophthora infestans is one of the most devastating diseases on potato worldwide. Partial resistance (PR) to the oomycete pathogen Phytophthora infestans was studied for ten potato cultivars in Beheira, Gharbia and Kafr El-Sheikh governorates in Egypt. Final disease severity (FDS%), area under disease progress curve (AUDPC) and rate of disease increase (r-value) were used as epiphytotic parameters to estimate PR during the growing seasons of 2016 and 2017. The cvs. Burren, Cara and Bellini exhibited the highest levels of PR to late blight, where they showed lowest values of FDS (%), AUDPC and r-value in both seasons of evaluation. Four measures i.e., means , regression coefficient (b 1), standard deviation (S 2 d) and ecovalance (wi) were used for determining the partial stability resistance of the tested potato cvs., to late blight infection. Stability parameters clearly showed that cv. Bellini was the most stable to late blight under wide range of environmental conditions. The stability analysis can help breeders to monitor the level of resistance of the tested plant material as well as to monitor the disease pressure in different environments.