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Background The use of natural preservatives became of great interest; good examples of these natural preservation agents are plant peels. The use of plant peels has dual benefits; first is their antimicrobial activity against food-borne pathogens, while the second is minimizing agro-industrial wastes. Results The evaluation of the antimicrobial potential of both methanolic and ethanolic extracts of three fruit peels (orange, pomegranate, and banana), against 4 Gram-positive (G+), 3 Gram-negative bacteria (G−), and 2 fungal strains revealed that both pomegranate peel extracts exhibited significantly higher inhibitory effect on all tested G+ bacteria. Methanolic extract of pomegranate peel gave higher activity than the ethanolic one against G+ and G− bacteria except for S. typhimurium. Against A. flavus and A. niger, both pomegranate and orange extracts showed activity ranging between 65 and 100% more than the positive control. The ethanolic extracts of all tested peels showed a considerable capacity of antioxidant compounds compared to the methanolic extracts. The highest antioxidant capacity was found for ethanolic and methanolic extracts of pomegranate, 66.870 and 56.262 mg/ml, respectively. Generally, the concentration of total phenolic compounds was higher than that of total flavonoids followed by tannins. The highest readings of all tested constituents were reported for pomegranate extracts followed by orange and then banana. The total phenolic content, total flavonoids, and tannins were proportional to antioxidant values. GC-MS of pomegranate peel extracts identified 23 compounds in the methanolic extract versus 31 compounds in the ethanolic one. These components were identified based on their retention times and mass spectral fragmentation pattern. 5-hydroxymethylfufural (HMF) represented the major component in both methanolic and ethanolic extracts with peak area percentage of 65.78% and 48.43%, respectively. Conclusions The results showed negative effect of methanolic and ethanolic extracts of pomegranate on G+ and G− bacteria and two fungal pathogenic strains. The phytochemical analysis regarded these results to the high content of phenols, flavonoids, and tannins. GC-MS chromatogram identified many compounds known to be effective as antioxidants and antibacterial and antifungal agents. These indications show that pomegranate peel may be a superior natural food-preserver, but further studies about the suitable formulation, dosage, and possible side-effects are still needed.

Insecticidal activity of the red pigment produced by a strain of the fungus Beauveria bassiana that was locally isolated from infected whitefly, Bemisia tabaci (Genn.) was assessed. The pigment is produced extracellularly and is a water-soluble. This makes it easy and simple to be recovered from fermentation broth and used in pathogenicity experiments. When applied alone to Bm. tabaci nymphs, mortality percentages of 18% was recorded. For nymphs treated with Bv. bassiana spore suspension, mortality was 60%. The best results were obtained when red pigment was combined with fungal spores with the mortality percentage being increased to up to 92%. The highest insecticidal activity against adults emerging later on from the surviving larvae of Bm. tabaci was recorded also with treatment combining pigment and fungal spores with the longest days to pupation.

In the present study, two of the most toxic bacterial strains of Bacillus sphaericus against mosquito were identified with the most recent genetic techniques. The PCR product profiles indicated the presence of genes encoding Bin A, Bin B and Mtx1 in all analyzed strains; they are consistent with protein profiles. The preliminary bioinformatics analysis of the binary toxin genes sequence revealed that the open reading frames had high similarities when matched with nucleotides sequence in the database of other B. sphaericus strains. The biological activity of B. sphaericus strains varied according to growing medium, and cultivation time. The highest yield of viable counts, spores and larvicidal protein were attained after 5 days. Poly (P) medium achieved the highest yield of growth, sporulation, protein and larvicidal activity for all tested strains compared to the other tested media. The larvicidal protein produced by local strains (B. sphaericus EMCC 1931 and EMCC 1932) in P medium was more lethal against the 3rd instar larvae of Culex pipiens than that of reference strains (B. sphaericus 1593 and B. sphaericus 2297). The obtained results revealed that P medium was the most effective medium and will be used in future work in order to optimize large scale production of biocide by the locally isolated Bacillus sphaericus strains.

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Twelve fungal isolates of the genus Fusarium were isolated from bread wheat grains infected with Fusarium head blight; 4 isolates of F. culmorum, 3 isolates of F. graminearium, 2 isolates of F. equiseti and F. moniliforme, and one isolate of F. avenaceum. The results obtained showed that all of these isolates caused head blight disease in wheat (Tamoz 2 cultivar). The isolates F. graminearium 2, F. graminearium 3 and F. culmorum 3 showed the highest Fusarium infection index (FII), which was 51.45, 50.37, and 50.03, respectively, whereas the lowest values were 24.61 and 32.04 for the isolates of F. culmorum and F.avenaceum, respectively. The identification of the most pathogenic isolates of F. graminearium 2 was confirmed by molecular diagnosis based on the matching of the nucleotide sequence of the 5.8S rRNA gene of this fungus with the nucleotide sequences of the fungal strains contained in the World Genbank database (listed on the NCBI website) and this isolate was recorded in Global Genbank under the accession number MT998864.1. The results obtained also showed that 12 of the studied wheat cultivars (Sham 6, Abu Ghraib, Babil, Milan, Sally, Hadbaa, Rabia, Bohoth 206, Sham 4, Iba 99, Dor 29 and Al Ezz) had the lowest infection levels compared to other cultivars. The FII values obtained suggested a significant superiority of the cultivars Sham 6, Abu Ghraib, Milan and Babel (which did not differ significantly among each other) with lowest values of 16.84, 16.86, 17.44 and 17.84, respectively. The effect of infection with FHB was reflected in the percentage of Fusarium damaged kernels (FDK), with lowest values of 38.43, 39.23, 41.58, 41.82 and 42.03% for the cultivars Sham 6, Abu Ghraib, Milan, Babel and Hadba, respectively. The electrophoresis of PCR products of Xgwm389, 6B NOR and Xgwm 126 markers associated with the resistance genes Fhb1, Fhb2 and Fhb3, respectively, carried out on twenty eight wheat cultivars showed that four cultivars (Sham 6, Abu Ghraib, Babel and Milan) produced bands of 140 bp in size for the marker of Fhb1 gene (Xgwm389), which is considered one of the indicators for resistance to FHB disease of wheat. The test also showed the presence of a single band of 220 bp in the wheat cultivar Sally for the gene marker Fbh2 (6B NOR), which indicates resistance to FHB disease. Whereas, the electrophoresis product for the gene marker Fhb2 (Xgwm 126) produced a band of 2100 bp in size, reflecting the presence of resistance characteristic in this cultivar. The results of this study indicated the presence of a relationship between the decrease in the infection parameters with the presence resistance genetic markers in the cultivars Sham 6, Abu Ghraib, Babel, Milan, Sally and Hadbaa, whereas the cultivars Rabia, Bohoth 206, Sham 4, Iba 99, Dor 29 and Al Ezz showed a decrease in infection parameters to a lesser degree than the remaining cultivars, but without the presence of the genetic markers investigated. Keywords: Fusarium head blight disease, molecular markers, resistance genes, wheat cultivars, Fusarium sp

In an attempt to develop a cost-effective process for bioinsecticide production by B. thuringiensis, the feeding regime during aerobic cultivation of the bacterium was investigated and optimized. The process was designed as a two-stage process; a first stage of active growth, where glucose and other nutrients were adequately supplied to the growing cells over 12 h, followed by a second stage of 2 h for spore formation and toxin release. In order to maximize spore and toxin yield and productivity, different quantities of glucose and nutrients were fed separately to the growing cells in four different fermentation runs. In all runs, glucose was converted to bacterial biomass during the first stage and subsequently to spores and crystal protein during the second phase. The best results were obtained with a fermentation run supplied with 190 g glucose in 1500 ml. Up to 20.1 g of bacterial insecticides/l were recovered from fermentation broth with a glucose to toxin conversion yield of 0.159 g/g. Also, a markedly high spore concentration of 2.31 9 10 12 c.f.u./ml was obtained. The spore-crystal protein mixture obtained was tested for its insecticidal activity against three of the most agronomically important pests. Among the bioinsecticide-treated insect pests, Egyptian cotton leafworm, Spodoptera littoralis was the most susceptible pest with the lowest LC 50 of the bioinsecticides against its larval instar and the highest virulence against adults emerged later on from the surviving larvae.