جستجوی مقالات مرتبط با کلیدواژه « Biological control » در نشریات گروه « زراعت »

The purpose of this experiment was to investigate the effect of foliar spraying of bacterial herbicides and aqueous extracts of plants on the morphological characteristics and starch of barnyard grass weed and rice.

This experiment was conducted as split factorial based on a randomized complete block design cityAmol with three replications in the two cropping years of 2018 and 2019. Factors included the foliar application of aqueous extracts plants and surfactant of sorghum, broccoli, nettle, eucalyptus, elder-berry, Streptomyces sp-albos containing thaxtomin, Xanthomonas campestris bacteria and control as the main factor, the concentration of the extract was zero, 5, 10 and 15 per thousand as a subfactor and the plant species of rice were Tarom cultivar and barnyard grass weed as a sub-sub factor.

By extracts foliar application, barnyard grass seed yield and biological yield decreased and the seed starch percent increased. Rice seed yield in the use of 5 per thousand broccoli extract and 5 per thousand Streptomyces sp-albos was not significantly different from the control. By increasing the concentration of the extract, seed yield and biological yield of rice and barnyard grass showed a further decrease. The lowest seed yield in rice at 3.16 tons/ha was related to elder-berry extract and in barnyard grass 0.68 and 0.61 tons/ha was related to nettle and elder-berry extract.

According to the obtained results, Allelopathy and plant pathogens can be one of the basic ways to control weeds in a sustainable agricultural system.

To evaluate the allelopathic and fungicidal effect of saffron leaf and corm aqueous extracts on the germination and growth characteristics of London rocket (Sisymbrium irio) and Fusarium solani, independent experiments were conducted as factorial arrangement based on the completely randomized design with four replications at the Faculty of Agriculture of Birjand University in 2022. Treatments to test the inhibitory effect of saffron extract on London rocket seed germination characteristics including two types of saffron organs (leaf and corm) and seven extract concentrations (0, 0.25, 0.5, 1, 1.5, 2, and 4 w/v %). Experimental treatments to investigate the inhibitory effect of saffron extract on the growth of Fusarium solani fungus including two types of saffron organs (leaf and corm) and seven extract concentrations (0, 1, 0.5, 25. 0, 0.125, 0.625, and 0.0312 w/v %). The results showed that the type of extract has an effect on the germination percentage, germination rate, mean germination time, length and fresh and dry weight of radicle, the length, fresh and dry weight of the plumule, seedling dry weight, and the seedling vigor of London rocket were significant, and the corm extract had more negative effects compared to the leaf extract. As the extract concentration increased, its inhibitory effect also increased. The extract concentration of 4% significantly reduced the radicle length and fresh and dry weight, the plumule length and fresh and dry weight, seedling dry weight, and seedling vigor of London rocket compared to the control. The results of the interaction showed that the lowest percentage of germination, germination rate, radicle length and fresh and dry weight, plumule fresh and dry weight and seedling dry weight of london rocket were observed at the concentration of 4 % corm extract. The results of the interaction effect of extract type and extract concentrations on Fusarium solani colony diameter showed that all the concentrations of corm extract inhibited the growth of Fusarium solani in all four stages of sampling. In leaf extract, concentrations of 0.125, 0.25, 0.5 and 1% completely inhibited the growth of Fusarium solani in all four stages of sampling. Finally, the results of these experiments showed that the effect of inhibiting the germination and growth of london rocket as well as the antifungal effect is greater in saffron corm extract than the leaf extract. Therefore, considering the results of this research and conducting more research in the field of allelopathic and fungicidal effects of saffron organ extracts, we can proceed to produce natural herbicides and fungicides.

AbstractThe use of soil fungi such as Fusarium is one of the strategies for controlling and managing parasitic plants. Accordingly, in order to evaluate the pathogenic potential, Fusariumoxysporum was isolated from the stems of infected plants of Phelipancheaegyptiaca and after identification, it was tested in a greenhouse using two treatments inoculated with fungal suspension. F. oxysporum and control treatment (no inoculation) were performed. In the inoculated treatment, fungal suspension with a concentration of 107 × 5 spores per ml, at a rate of 50 ml per pot and in the control treatment, tap water was used. Studied traits were including total number of parasite stems, number of parasite stems removed, number of diseased and dead parasite stems, number of healthy parasite stems, and number of flowering stems, number of parasite stems per plant, stem height of the parasite and the dry weight of Egyptian broomrape and tomato plants. The results of comparing the mean of the two treatments with t-test showed a significant difference in the dry weight of broomrape and tomato so that the mean dry weight of broomrape in the treatment inoculated with F. oxysporum (6 g), compared to the control treatment (16.84 g), was 2.8 times lower. Also, the highest dry weight of tomato (36.43 g) was observed in the inoculated treatment with F. oxysporum, which increased by 44.27% compared to the control with 25.25 g. In the host range test, none of the tested plants showed signs of persistent infection, including permanent wilting and necrosis. In general, the use of this fungus in the biological control of Egyptian broomrape could have an effect on all studied traits, reduce the dry weight of Egyptian broomrape and increase the dry matter of tomato.

One of the most important pathogens in plants such as pomegranate, are root-knot nematodes (Meloidogyne spp.) which cause considerable damage to this important export product. Due to the importance of this subject, an study has been conducted between 2018 and 2019 in the Faculty of Agriculture of Lorestan University. The treatments include organic fertilizer (40, 60, and 80 t/ha.), vermicompost (40 t/ha.) and Marygld product (200, 300 and 400 g/m2) with the study, itself, being in a completely random design on the dominant root-knot nematodes species, M. javanica under greenhouse conditions on pomegranate seedlings. The measurement indicators include gall index, the number of egg sacs, and the final population of egg and J2 larvae in the soil and the roots, as well as growth factors of pomegranate seedlings. Reproduction factor and the percentage of increase/decrease of root knot nematode population, have been calculated in each treatment compared to the initial population of the same treatment. Results show vermicompost (40 t/ha.) with 94.35% reduction in population of egg and larvae has had the highest effect on reducing the nematode population compared to other treatments. Marygld 400, 300, and 200 g/m2 treatments are ranked next, with a reduction of 93.47%, 91.21%, and 92.65% in nematode population, respectively followed by by nematode reduction of the composts of 80, 60, and 40 t/ha by 89.67%, 86.55%, and 86.81% respectively.

In order to investigate the environmental biological control of soybean charcoal rot disease by using the mutated formulation of Trichoderma Harzyanum with gamma ray, factorial field experiments in a completely randomized block design for morphological traits was performed in a farm located in Islamshahr in 2018-2019. The experiment consisted of 12 treatments including control, application of commercial biological fungicide of Trichoderma, soybean and inoculation of mutant and non-mutant Trichoderma fungi in powder and granules. The results showed that the effect of treatments was significant for all soybean morphological traits. The use of Trichoderma fungi treatments increased the quantitative amount of morphological traits such as grain yield, total dry weight, number of pods per plant, number of sub-branches, plant height, number of seeds per pod, one thousand seed weight, number of seeds per plant, harvest index, protein content and oil content, so that the highest average grain yield belonged to granular mutant Trichoderma and powder mutant Trichoderma treatments with averages of 3531.25 and 3527.5 kilogram per hectare, respectively. The results also showed that the interaction of formulation and pathogen in the number of pods per plant in the treatments of granular mutant Trichoderma and pathogenic powder mutant Trichoderma with 47 pods had the highest rate.

Wilt and root rot diseases caused by Fusarium oxysporum and Fusarium solani are among the most important diseases of chickpea throughout the world and Iran. However, there is not effective chemical fungicide against these soil-borne pathogenic fungi. In recent years, rhizospheric bacteria and fungi developed as promising biofungicides against soil-borne plant pathogens. These microbes exploit several mechanisms such as antibiotics, volatile organic compounds, sidereophore and induced systemic resistance to suppress pathogenic fungi. Recently, the cost of agrochemical innovation and the period of time for their registration have increased rapidly due to stringent legislation, both of these reasons favor investment in the manufacture of biopesticides. The annual progress rate of the biopesticide bazaar is more than 16%, but that of synthetic pesticides has been decreasing by 1.5% annually. Biopesticide companies such as Agroquest, Gustafson, Marrone Bio Innovation, Certis, BioWorks, Becker Underwood, ABiTEP GmbH, and Prophyta have released effective biopesticides to the market. Agrochemical great-companies such as Bayer CropScience have also been engrossed in the bio-pesticide market. Bayer CropScience bought Agroquest in 2012 at a price of 425 million US dollars. Overall, biological control of plant pathogens is promising technology in management of plant disease in sustainable agriculture.

 In this study, potential of plant growth promoting rhizobacteria (PGPRs) were investigated on biological control of this diseases in laboratory and greenhouse condition. Soil samples were collected from chickpea fields in Kermanshah and Kurdestan provinces. The effect of isolated bacteria were assessed on mycelial growth of F. oxysporum and F. solani in dual culture test. The chickpea seeds were inoculated by 109 CFU/ml of each bacterial isolates and sown in pots. The effect of bacterial isolates have been investigated on plant growth factors in greenhouse situation. The same experiment was conducted to assess the biocontrol ability of selected isolates against Fusarium wilt and root rot disease of chickpea. The greenhouse experiments were conducted based on completely randomized design with four replicates. Data were subjected to analysis of variance procedure in SAS ver. 9.1 software and means compression analysis was done by Fisher protected LSD. Finally, the 16S rDNA of the four selected isolates, B2, B3, B6 and B13 were sequenced and identified based on Genebank data.

Sixteen out of 100 isolated inhibited the growth of both fungi in vitro. Isolates B13 with 11 mm inhibition zone had the highest growth inhibition activity against F. oxysporum. In absence of pathogens, B2 increased aerial part dry weight from 1.08 to 3.69 g in greenhouse condition. B3 and B4 were the best isolates in improving root growth. They increase root dry weight to 1.42 and 1.36 g, respectively. B2 and B13 isolates had the greatest effect on plant health and reduced disease severity up to 90% in F. oxysporum inoculated plants. The lowest biocontrol activity against F. oxysporum was recorded for isolate B6. B2 increased aerial part fresh weight from 0.56 to 2.49 g, root fresh weight from 0.24 to 1.31 g. B6 was the best isolate for suppression of F. solani and reduced the disease index by 73%. This isolate increased aerial organs fresh weight as up to 3.2 folds and root fresh weight up to 2.9 folds. However, all of bacteria isolates were able to reduce Fusarium root rot disease, significantly. Isolates B2, B3, B6 and B13 were characterized as Bacillus sp., Achromobacter sp., Bacillus pumilus and Burkholderia sp. based on 16S rDNA sequencing, respectively. Bacillus spp. strains exploit several mechanisms such as antibiosis, volatile organic compound production and induced systemic resistance against plant pathogens. These bacteria are good candidate to be formulated in spore suspension form. Here, Achromobacter introduced as good candidate for biological control of Fusarium diseases of chickpea for first time. Overall, plant probiotic bacteria could be consider as promising approach in management of chickpea Fusarium diseases.

Bacterial isolates have different ability in plant growth improvement and suppression of plant pathogens. Bacillus sp. was the best isolate for enhancing the shoot dry weight while Achromobacter sp. was the best to improving root dry weight. Indeed, bacteria have several mechanisms for promoting plant growth. Auxin induction by volatiles of Bacillus spp. increase root while decreasing the shoot accumulation of auxin. Overall, consortia of bacteria strains seems to be promising approach to suppression of both diseases in chickpea.

The saffron (Crocus sativus - Iridaceae) or red gold is an invaluable and economic agricultural crop which is important for exportation. Saffron fields comprises some agricultural pests same as other crops which are active in different regions of Iran and damge to it. In this faunistic survey, the fauna of beneficial Arthropoda (predators and parasitoids) was studied in some saffron fields of Iran (Southern Khorasa, Razavi Khorasan, Kerman, Fars and Lorestan provinces). In total, 31 predator insects within five orders, Coleoptera (Carabidae, Staphylinidae), Diptera (Asilidae, Syrphidae), Hymenoptera (Formicidae), Thysanoptera (Thripidae) and Heteroptera (Anthocoridae, Miridae, Nabidae, Reduviidae), and also five species of Araneae (spider) and five species of Acari were collected and identified as the predator arthropods. Additionally, 26 species of parasitoids in two orders, Diptera (Tachinidae) and Hymenoptera (Braconidae, Chalcididae, Eulophidae, Ichneumonidae, Pteromalidae) were collected from saffron fields too. Among the collected natural enemies, three species Apechthis capulifera (Kriechbaumer, 1887), Virgichneumon albilineatus (Gravenhorst, 1820) and Netelia melanura (Thomson, 1888) (all Ichneumonidae) are new records for the fauna of Iran. Upon the present investigation, totally 67 species of predator and parasitoid arthropods were collected from saffron fields and neighbouring areas which this high diversity of natural enemies is invaluable and important in biological control of agricultural pests.

The current study been conducted to achieveto effective antagonists for diseases control of seedling damping-off greenhouse pepper, casead by Rhizoctonia solani. Experiments has conducted based on completely randomized design in the faculty of agriculture and natural resources of Lorestan University in 2016-17. First, the fungi and biological agents were isolated and identified of the rhizosphere of Solanaceae plants. The antagonistic ability of fungal and bacterial isolates, such as Trichoderma harzianum and Trichoderma virens fungi and Bacillus subtilis bacteria, against R. solani was studied by using dual culture method. As well as antagonistic ability of fungal and bacterial agents and Trichomix HV biological fungicide were study in a greenhouse condition. The results showed that both species of T. harzianum and T. virens the prevented growth of fungi 9.45 and 15.59 percent respectively by colonization and sporulation in PDA. Antagonistic bacterial also caused effects such as outpour of the contents of hyphae, color change at the tip of hyphae, thinning and reduction of mycelium up to 8.47 percent. Also, results in greenhouse condition showed that B. subtilis and T. harzianum treatments have the most positive effects on growth traits such as height and weight (wet and dry) of the root and stem and reduced the severity of the disease up to 60.33 and 70.33 respectively; therefore they are the best antagonistic agents to control R. solani on pepper.

In the present study, natural active enemies of pests in sugar beet fields in some regions of Iran including Gonbad, Ramian, Agha Qala (Golestan province), Nahavand (Hamadan province), Fereydoun-Shahr, Borkhar, Golpayegan (Isfahan province), Shahrekord (Chaharmahal & Bakhtiari province), Naghadeh, Miandoab (West Azarbaijan province) were studied. A total of 45 species of natural enemies including 10 parasitoids and 35 predators of the order, Hymenoptera (Braconidae: seven species in six genera; Ichneumonidae: single species), Diptera (Tachinidae: two species in two genera; Asilidae: four species in four genera; Syrphidae: three species in three genera), Coleoptera (Carabidae: seven species in six genera; Coccinellidae: five species in four genera), Hemiptera (Anthocoridae: six species in two genera; Miridae: five species in three genera; Nabidae: two species in two genera; Reduviidae: two species in two genera), and Neuroptera (single species from the family Chrysopidae) were collected and identified in different parts of the country. Due to high diversity of natural enemies in sugar beet fields, the support of these beneficial insects is necessary in order to reduce the consumption of chemical pesticides, and the success of natural enemies effectiveness.

The field experiment to study the effects of intercropping on weed control, in the Agricultural Research Station of Lorestan University of 2014-15 and 2015-16 in 4×5 factorial randomized complete block design with three replications, in two consecutive years in one place was carried out on dry land. In this experiment, two plants (legume and cereal or broad leaf vetch and barley cultivar Abidar) in the form of additive series intercropping system with four levels of weed (weeding, once weeding, double weeding and non-weeding) and complementary components of intercropping in five levelsThe lowest number of weeds (in square meters) of first and second year with a mixture of 100: 70 (barley:vetch) was equivalent to 21 and 21.35, sole cropping of barley was the lowest greatest weight weed control (34.54 g/m²). the levels mix, combination of 100: 40 and 100: 70 most of the weeds dry weight, respectively (24.56 and 23.77 gr/m2). So, at the mentioned levels (intercropping balanced) efficiency of weed control in the second year was than the first year. Also, by reducing the share of vetch from 100 to 70 and 40 percent, the exploitation of the environment reduced and minimum LERt in the second year and different levels of weed was belonged to 40:100 seed ratio.