خيارات البحث
النتائج 811 - 820 من 1,443
Evaluation of Certain Synthetic and Natural Pesticides Against Whitefly Bemisia tabaci (Genn.) on Green Bean and Effect on Honeybee Apis mellifera L.
2023
Sharihan Ahmad | Walaa Abdelghany | Ahmed Ahmed | Sawsan Abdelmegeed
The green bean crop (Phaseolus vulgaris) is infested with many insects such as whiteflies (Bemisia tabaci). An investigation was carried out to study the insecticidal activity of whitefly (Bemisia tabaci), five pesticides were used, namely Thiamothoxam, Sulfoxaflor, Spirotetramat, Pymetrozine, and Flonicamid, and three commercial natural pesticides, namely Superrego, Topnine, and Bernastar. Pesticides and natural pesticides were sprayed during the two seasons of 2020 and 2021. The obtained results in terms of the reduction rate of the insects' number were as follows: The highest rate of reduction appeared in Thiamothoxam and Sulfoxaflor treatments, where it reached above 80%, while the other pesticides were in the range of 40% to 60%, and the lowest reduction rate was 34.33% and 36.00 % for Bernastar during season 2020 and 2021 respectively. When evaluating the toxicity of these pesticides and natural pesticides against honeybees (Apis mellifera), the pesticides did not reveal any toxicity to honeybees, except for Thiamothoxam, Sulfoxaflor, and Superrego The LC50 and LD50 values against honeybees were 0.2 ppm and 0.000005µg/one honeybee for Thiamothoxam, 4.5 ppm and 0.0001125 µg/one bee for Sulfoxaflor, and 0.95 ppm and 0.00002375 µg /one bee for Superego respectively.
اظهر المزيد [+] اقل [-]Role of Vitamin C Supplementation in Alleviation of Aflatoxin-Contaminated Feed of Nile tilapia (Oreochromis niloticus)
2023
Sara El-Nahal | Mohamed Amer | Mohamed Osman | Kareem Ahmed
The purpose of the research was to illustrate the effects of feeding Nile tilapia fingerlings (Oreochromis niloticus) with low doses of aflatoxins (AFs) with and without vitamin C supplementation to investigate the capacity of vitamin C in detoxification. Ten experimental diets were formulated and divided into three categories. The first category included: T1, T4 and T7 feedings included 20, 40 and 80 μg AFs kg−1 feed respectively, while both the second category T2, T5 and T8 and the third category T3, T6 and T9 were treated with contaminated feed with AFs for 57days then both categories shifted to different regime till the conclusion of the experimentation. The second category was fed uncontaminated feed while the third category was fed a supplemented diet with 100 mg Kg-1 of vitamin C. For 113 days the experiment was conducted. The results showed that shifting from a contaminated diet to an uncontaminated diet (category 2) or adding vitamin C to the contaminated diet (category 3) improved the deterioration that occurred in the values of growth performance, biochemical parameters and histological disorders caused by AFs. Furthermore, the results from the control group were superior to all the treatments.
اظهر المزيد [+] اقل [-]Efficacy of Potassium Fertilizer and Certain Pesticides for the Management of Brinjal Fruit Infection by Shoot Borer [Leucinodes Orbonalis (Guenée)]
2023
Sagar bhandari | Bikash kandel | Pramod gyawali | Saurav pokhrel | Sushil ojha | Sarita bhandari
The research aims to evaluate the efficacy of different levels of potassium fertilizer (8 g/plant K2O) as well as the insecticides neemix, spinosad, and imidacloprid at the rates of 6 ml, 0.33 ml, and 0.33 g/L water, respectively, for the management of brinjal fruits and shoot borer. The two-factor randomized complete block design with three replications was used. Significant minimum shoot damage was recorded in the plots treated with imidacloprid (0%), spinosad (1.67%) and neemix (5.0%) at 81 days after planting. Similarly, a significant minimum fruit infestation (2.90%) was recorded with imidacloprid, which was lower than those of spinosad (15.16%) and neemix (19.63%). The application of potassium fertilizer at a rate of 8 g/plant showed a significant reduction in shoot infestation (2.50%) 81 days after planting. The minimum percentage yield of infested fruit was reported with spinosad (1.03%), which was at par with other insecticidal treatments. Considering the negative impacts of chemical pesticides, neemix 6 ml/L water in combination with potassium fertilizer at 8 g/plant is recommended.
اظهر المزيد [+] اقل [-]Harvesting Microalgae by Chitosan as Sustainable Biopolymer
2023
Ola Obyd | Ayman Abou Hadid | Shawky Selim | Tarek El-Arabi
This study aimed to use the organic polymer, chitosan, as a flocculant for harvesting microalgae Chlorella. sp. Various polymer concentrations were tested. Within three min, 50 mg/L of chitosan showed the highest efficiency (98.9±0.5%), at pH 6.3, while the lowest efficiency (86.7±0.5%) was observed at pH 7.5. Harvesting efficiency in this study was chitosan concentration dependent. The present study showed that chitosan can be a promising and sustainable solution as an organic source and environmentally friendly flocculant. Additionally, it has excellent harvest productivity and requires minimum effort for quick outcomes.
اظهر المزيد [+] اقل [-]Isolation and Identification of Some Egyptian Ectomycorrhizal Sporocarps
2022
Aya Ahmed | Shawky Selim | Mona Zayed | Asmaa Ahmed | Dalia Abd El-Fattah
In contrast to the global countries, ectomycorrhizae members are not common in Egypt, however, they are very important in the afforestation of poor lands. Their occurrence in Pinus sp., Clerodendrum sp., and Eucalyptus sp. may help to explain why these trees are the most extensively dominant around the world, especially in Egypt. The identification and characterization of numerous ectomycorrhizal fungi often involve large morphological descriptions of sporocarps alone, which consequently, in some instances, raise arguments about the accuracy of these studies. The present work was achieved to isolate, identify, and characterize three ectomycorrhizal fungi from sporocarps combining morphological and molecular techniques. The morphological characteristics of tested species were assessed and compared to standard taxonomic literature. ITS-rDNA was utilized for molecular analysis using the universal fungal primers ITS1. Identification of these species was confirmed by comparing the sequences of amplified genomes of these species with respective species sequences in GenBank, followed by blast analysis.
اظهر المزيد [+] اقل [-]Element Composition and Toxicity of Seaweed Algae (Ulva lactuca, Laurencia obtuse and Padina pavonica) Toward Shrimp
2022
Ahmed Muhammad | Ibrahim Hassan | Manar Tawfeek | Hayam Ahmed Ibrahim
This study examined the macro and trace element contents as well as the cytotoxicity of Laurencia obtusa, Ulva lactuca, and Padina pavonica algae collected from the Mediterranean coast of Egypt (Alexandria coast). The results indicated that the seaweed samples contained high concentrations of Ca, Cl, Mg, K, Na, P and Fe. The Cu and Zn contents of the algae were in the ranges of 0.39-0.95 mg/100 g dw and 0.11-0.49 mg/100 g dw respectively. Fresh red algae contained the highest level of Zn and Cu, whereas the iodine level was 1.52, 1.27 and 1.01 mg/100g in fresh each of Padina pavonica, Laurencia obtuse and Ulva lactuca respectively. Fresh red, fresh green, dry green, dry red, in addition to fresh and dried brown algae had maximum lead (Pb) levels of 0.16, 0.14, 0.13, 0.12, 0.04 and 0.02 g/100 g respectively. Fresh red algae contained the highest Cd and Mn levels, whereas dried brown algae exhibited the lowest Cd and Mn concentrations. Different extracts of fresh and dried brown algae exhibited significant larvicidal activity against brine shrimp. LC50 values indicated that dry samples were more cytotoxic than fresh samples.
اظهر المزيد [+] اقل [-]Seasonal Effects on Some Eco-Morphological and Physiological Characters of Tamarix nilotica (Ehrenb) Bunge Growing Naturally in Egyptian Northern Coastal Salt Marshes
2022
Aya Mehanny | Gamal Khalifa | Ola Abd Elbar | Sami Habib | Maryam Abba Dawud
Tamarix nilotica is a perennial halophyte growing naturally at the Mediterranean coastal salt marshes. Vegetative parts were collected in two successive winters and summers to investigate the seasonal effects on the ecomorphological and physiological responses of T. nilotica. The results indicated that either in winter or summer seasons, T. nilotica can reduce the effect of soil salinity by excreting salts outside its body through salt glands. Summer season was characterized by low content of soil moisture (due to rare rainfall), high soil EC, high light intensity and high temperature; there-fore, plant induced certain morphoanatomical changes in leaves and stem to face the previously mentioned adverse conditions. The most remarkable changes to reduce transpiration process was found by decreasing leaf area and increasing cuticle thickness and mesophyll tissue thickness. In addition, the most marked physiological changes in summer were the significant in-crease in total phenols, proline, free amino acids and total soluble sugars. These compounds can work as osmotic regulators and/or antioxidants. These features enhance the defensive mechanism against dehydration and permit T. nilotica to tolerate the stress conditions in salt marsh habitat.
اظهر المزيد [+] اقل [-]Evaluation of Some Essential Oils Against Wax Moth Larvae (Lepedoptera: Galleria mellonlla L.) and Adult Honeybee Workers (Hymenoptera: Apismellifera L)
2022
Ekbal Helaly | Mahmoud A Ali | Naglaa Ghazala
This study was conducted to investigate the effects of five essential oils (garlic, Allium sativum; camphor, Cinnamomum camphor; menthol, Mentha sp.; cinnamon, Cinnamomum erum; and clove, Dianthus sp.) on wax moth larvae and adult honeybee workers under laboratory conditions. Cinnamon, garlic, menthol, clove, and camphor oils were found to be highly effective against wax moth larvae, with 100 percent mortality achieved after 48 and 96 hours for cinnamon and garlic oils respectively, and after 120 hours for clove and mint oils. Camphor oil provided 96.60% accumulative mortality after 120 hrs. Moreover, all the essential oils were highly safe for adult honeybee workers under laboratory conditions. Accumulative corrected mortality rates after 72 hr were 15.96, 9.02, 13.18, 29.16, and 8.88% for treatments with cinnamon, clove, camphor, mint, and garlic oils respectively.
اظهر المزيد [+] اقل [-]Improvement of Growth and Productivity of Mango Trees Using Some Growth Stimulants under Salinity Conditions
2022
Fatma Abdalla | Hassan Elwakeel | Noha Mansour | Sabry Osman
A study was carried out in a mango orchard on reclaimed land for two seasons in 2019 and 2020. The experiment was implemented on fifteen years old mango trees “Fagri Kalan” budded on seedling mango rootstock and planted at 4 × 4 m. This experiment involved two soil growth stimulants (K humate, magnetite) and foliar application with cobalt. The experiment involved two factors, the first one was soil application with K humate by two levels (50 and 100 g/tree/year) and magnetite by two levels (250 and 500 g/tree /year) plus control, whereas the second factor was a foliar application with Co as cobalt sulfate by three levels (0, 15, and 30 ppm Co). The experiment was carried out in a factorial experiment in split plot design with three replicates whereas each replicate was represented by two trees. Result indicated that soil application with K humate at 100 g/tree followed by magnetite at 250 g/tree or foliar application with Co at 15 ppm alone or the combination between (K humate at 100 g/tree and cobalt at 15 ppm) gave the highest values of yield/tree, fruit weight, TSS, reducing sugars, leaf N, P, K, and Fe content of “Fagri Kalan” mango trees grown under salinity conditions.
اظهر المزيد [+] اقل [-]Productivity Improvement of Canola Genotypes Under Salinity Stress Conditions by Integration between Mineral and Nano-Scale forms of Nitrogen Fertilizer
2022
Doaa Mohamed | Mohamed Fergany | Elsayed Elhabbasha | Mohamed El-temsah
Two field experiments were conducted during in 2019/20 and 2020/21 seasons to study the impact of integration among mineral and nanoparticle nitrogen (N) fertilizer levels on yield traits and chemical characters of some canola genotypes grown under salt stress conditions. Four treatments of N fertilization (190 kg N/ha as recommended dose; 50% of the recommended, 95 kg N/ha+nano nitrogen (5 L/ha); 25 % of the recommended, 47.5 kg N/ha+nano-nitrogen (5 L/ha), and nano-nitrogen (rate of 5 L/ha). canola genotypes (Trabber, Agamax, and Serw4) performance were assessed under three levels of saline irrigation water (control, 2000, and 4000 mg L-1). Results showed that increasing salinity levels up to 4000 mg L-1 led to decreasing in all studied yield parameters compared with those of control (tap water). Trabber genotype excelled significantly in most of the yield characteristics. Integration between nanoscale and mineral nitrogen fertilizer, i.e. 95 kg N/ha+5 nano N L/ha) showed superiority over all applied N treatments, recording the highest values. It could be concluded that since application of 95 kg N/ha+5 nano N L/ha exploiting the nano form of N saves about 50% of applied nitrogen in canola under saline conditions. Accordingly, nanoparticles help the environmental pollution to be reduced.
اظهر المزيد [+] اقل [-]