Reduced Root Rot Research Articles

Role of Hydrogen Peroxide (H2O2) and Trichoderma koningii in Reducing Root Rot Disease of Tomato Causing by Fusarium solani

Two isolates of the pathogenic fungus Fusarium solani the causative of tomato root rot disease named Fs1 and Fs2 were isolated from tomato plants infected with root rot disease. Results showed that both examined isolates had significant effects on the percentage of seed germination of tomato and damping-off disease. Thus, isolate Fs1 was more effective than isolate Fs2, as it recorded a percentage of germination and damping-off 56.6 and 71.6% respectively, compared to the control treatment, which recorded 100 and 0% respectively. It was found that the use of hydrogen peroxide (H2O2) at concentrations of 50, 100 and 200 ppm had a significant effect on the fungal radial growth, dry weight (DW) and sporulation of F. solani. Antifungal activity of H2O2 appeared even at the lowest concentration (50 ppm), which inhibited radial growth to 49.33%, and decreased the dry weight to 498 mg, and the sporulation to 3.75×106 spores. Additionally, the results indicated significant inhibitory effects of hydrogen peroxide (H2O2) and the bioagent Trichoderma koningii on F. solani growth. It was noticed that H2O2 has compatible effects with T. koningii, where the antagonistic ability of T. koningii against F. solani increased when the concentration of H2O2 had increased. The results revealed that the treatment F. solani + H2O2 (200 ppm) + T. koningii significantly reduced the percentage of damping-off and plant survival to 9.40 and 5.39% respectively, in comparison with the control treatment and F. solani alone treatment, which reached 20.22, 14.48, 34.32 and 67.41% respectively.

Bio-synthesis and characterization of silver nanoparticles from Trichoderma species against cassava root rot disease

Cassava root rot disease caused by the fungal pathogens Fusarium solani and Lasiodiplodia theobromae produces severe damages on cassava production. This research was conducted to produce and assess silver nanoparticles (AgNPs) synthesized by Trichoderma harzianum for reducing root rot disease. The results revealed that using the supernatants of T. harzianum on a silver nitrate solution changed it to reddish color at 48 h, indicating the formation of AgNPs. Further characterization was identified using dynamic light scattering (DLS) and scanning electron microscope (SEM). DLS supported that the Z-average size is at 39.79 nm and the mean zeta potential is at − 36.5 mV. SEM revealed the formation of monodispersed spherical shape with a diameter between 60–75 nm. The antibacterial action of AgNPs as an antifungal agent was demonstrated by an observed decrease in the size of the fungal colonies using an increasing concentration of AgNPs until the complete inhibition growth of L. theobromae and F. solani at > 58 µg mL−1 and at ≥ 50 µg mL−1, respectively. At in vitro conditions, the applied AgNPs caused a decrease in the percentage of healthy aerial hyphae of L. theobromae (32.5%) and of F. solani (70.0%) compared to control (100%). The SR-FTIR spectra showed the highest peaks in the first region (3000–2800 cm−1) associated with lipids and fatty acids located at 2962, 2927, and 2854 cm−1 in the AgNPs treated samples. The second region (1700–1450 cm−1) consisting of proteins and peptides revealed the highest peaks at 1658, 1641, and 1548 cm−1 in the AgNPs treated samples. The third region (1300–900 cm−1), which involves nucleic acid, phospholipids, polysaccharides, and carbohydrates, revealed the highest peaks at 1155, 1079, and 1027 cm−1 in the readings from the untreated samples. Finally, the observed root rot severity on cassava roots treated with AgNPs (1.75 ± 0.50) was significantly lower than the control samples (5.00 ± 0.00).

New fungicides for managing Phytophthora diseases of tree crops with foliar and soil applications

Four new modes of action, oxathiapiprolin, fluopicolide, mandipropamid, and ethaboxam, have or are pending registrations on multiple tree crops in the USA including avocado, citrus, almond (and other tree nuts), and stone fruits to be used in sustainable anti-resistance rotation and mixture programs for managing Phytophthora diseases. All four fungicides are highly toxic in vitro against species of Phytophthora from different tree crops. Efficacy of foliar applications of oxathiapiprolin and mandipropamid for the management of citrus brown rot persisted for over 10 weeks. Still, residues could be removed to non-detectable levels by postharvest washing and brushing of fresh-market fruit. The four fungicides were highly effective in reducing root rot and crown/trunk cankers on tree crops and demonstrated acropetal systemic movement through the xylem after soil application and absorption by almond, citrus, and cherry roots. This was substantiated by reduced lesion size in stem inoculations of potted trees that were treated by soil applications or by in vitro bioassays and HPLC–MS–MS analyses of root, stem, and leaf extracts. Using an adapted Bromilow model that is based on the partition coefficient logP that indicates the lipo- or hydrophilicity and the acid dissociation constant pKa, mobility of ethaboxam, fluopicolide, mandipropamid, and oxathiapiprolin in plants was predicted, and this was supported by our studies. Mandipropamid and a mandipropamid–oxathiapiprolin pre-mixture are now registered as foliar applications for managing citrus brown rot, whereas oxathiapiprolin and fluopicolide are registered, and ethaboxam is pending registration as soil applications to control citrus root rot. Oxathiapiprolin has also been registered for soil use on almond and other nut crops, as well as avocado, and soil applications of mandipropamid are planned to be restricted to nursery use of multiple crops.

Bio- and synthetic fertilizers for reducing root rot and wilt and improving growth and flowering characteristics of rose

Root rot and wilt diseases are among the most pressing obstacles to the production of rose flowers in Egypt. Isolation results showed that these diseases are mainly caused by seven soil-borne fungi. However, Fusarium roseum, Verticillium dahlia, and Rhizoctonia solani were the most pathogenic fungi against Rosa gallica and R. chinensis compared to other isolated fungi. The present study aimed to investigate the potential of some bio- and synthetic fertilizers, including seaweed extract, Rhizobacterin, NPK, and potassium silicate, as well as the chemical fungicide vitavax 200, to control root rot and wilt and improve growth and flowering traits of both R. gallica and R. chinensis. Under in vitro conditions, the highest linear growth inhibition of pathogenic fungi was achieved by seaweed extract followed by potassium silicate, at 400 ppm each. In addition, vitavax 200 at 400 ppm completely inhibited the linear growth of these fungi. The results also showed that all treatments applied in vivo significantly reduced the incidence of diseases on rose plants in both seasons, leading to an improvement in all growth and flowering parameters and an increase in the content of photosynthetic pigments, total carbohydrates, nitrogen, phosphorus, and potassium. In this regard, seaweed extract (4 and 2 g/L) and potassium silicate (4 g/L) were the most efficient, while Rhizobacterin (2 g/L) and NPK (2 g/plant) were the least effective. However, vitavax 200 was the most effective of all the treatments used. In conclusion, the results proved the possibility of increasing the tolerance of R. gallica and R. chinensis against root rot and wilt, while improving growth and flowering characteristics by using some bio- and synthetic fertilizers.

Перспективы применения различных органоминеральных удобрений на яровом ячмене

The results of field experiments on spring barley conducted in 2023 on the experimental fields of the Agrobiotechnopark of the Kazan State Agrarian University are presented. The purpose of the research was to assess the impact of the use of various compositions of organomineral fertilizers based on natural minerals (zeolite, diatomite, perlite), humates and food industry waste (buckwheat husk, beet molasses) developed at the Institute of Agrobiotechnologies and Land Management of Kazan State Agrarian University on the formation of the yield and grain quality of spring barley. The objectives of the research included studying the nature of changes in plant growth and development, yield and protein content in grain when using experimental organomineral fertilizers. The object of the study was spring barley of the Raushan variety. The control was the option without fertilizers; the standard was the application of 100 kg/ha of azofoska. Experimental fertilizers were applied at a rate of 120 kg/ha. All fertilizers in the experiment were applied before sowing. The studies were carried out on gray forest highly cultivated soil. The growing season conditions in 2023 were characterized by periodically severe drought phenomena, which affected the growth and development of spring barley plants. It was found that the application of experimental fertilizers contributed to the growth of the length of roots and above-ground parts of plants, and also reduced the damage to plants by root rot. Diatomite-based fertilizer had the greatest positive effect on reducing root rot damage. The largest increase in yield over the control (by 0.73 t/ha) and standard (by 0.22 t/ha) was obtained when using diatomite-based fertilizer. The use of all organomineral fertilizers (especially those based on zeolite) leads to an increase in the protein content in the grain.

Enhancing sugar beet yield and quality in Northeast China: Investigating the synergistic impact of sugar mill filter mud and biochar on black soil

In this study, different ratios of sugar beet sugar factory filter mud and biochar in different proportions were used to assess the effect of incorporating filter mud into the field on soil quality and its influence on two distinct sugar beet (Beta vulgaris) varieties: high-yielding KWS9147 and high-sugar KWS1176. The experiment was conducted in 2022 at the Hulan Campus of Heilongjiang University in Harbin City, Heilongjiang Province, China. Eight treatments were employed, including CK1 (no filter mud or biochar application), CK2 (20 t/ha biochar), T1 (16.67kg/ha filter mud), T2 (16.67 t/ha filter mud + 20 t/ha biochar), T3 (33.33 t/ha filter mud), T4 (33.33 t/ha filter mud + 20 t/ha biochar), and T5 (50kg/ha filter mud). For sugar beets, parameters such as the SPAD value(Soil and Plant Analyzer Development, represents the relative content of chlorophyll), disease resistance (root rot and brown spot), tuber yield, and sugar content were evaluated. Soil analysis included nitrogen content, available potassium content, available phosphorus content, and soil sucrase, urease, and phosphatase activities. Results indicated that the combined application of 16.67 t/ha filter mud and 20 t/ha biochar had a positive impact on the growth indices, tuber yield, sugar content, effective phosphorus, and quick-acting potassium content in KWS1176. In contrast, for KWS9147, the most favorable effect was achieved with the application of 16.67 t/ha filter mud. This treatment improved plant leaf growth, increased tuber yield and sugar content, reduced root rot incidence, elevated alkaline dissolved nitrogen content in the inter-root soil, and enhanced soil phosphatase activity. Biochar application did not contribute significantly to these improvements. Therefore, returning sugar mill sludge to the field demonstrated its potential to enhance soil quality, promote the yield of sugar beet varieties, and improve resistance to root rot while also providing an eco-friendly solution for managing environmental issues related to sludge accumulation.

Antagonistic activity of Trichoderma asperellum against Fusarium species, chemical profile and their efficacy for management of Fusarium-root rot disease in dry bean.

Diseases caused by Fusarium pathogens lead to significant yield losses on many economically important crops. The purpose of this study was to evaluate the antagonistic capability and chemical profile of the bioagent Trichoderma asperellum against several Fusarium strains. The efficacy of this strain in reducing Fusarium-root rot disease in dry bean was also examined. The T. asperellum strain was identified based on sequencing the internal transcribed spacer (ITS) and tef1 gen regions of ribosomal DNA. Dual cultural assay demonstrated their antagonistic activity against the studied Fusarium strains due to the probable combination of competition, mycoparasitism and antibiosis. This strain was positive for cellulase, chitinase and protease activity. The crude extracts of T. asperellum significantly suppressed the growth of the tested Fusarium strains with inhibition zone values ranging from 7.3 to 19.7 mm and minimum inhibitory concentration (MIC) values ranging from 0.15 to 1.42 mg mL-1 . The gas chromatography-mass spectrometry (GC-MS) analysis of cell free supernatant and mycelial biomass of T. asperellum showed the presence of 27 and 21 compounds, respectively. The main compounds responsible for the bioactivity were butylated hydroxytoluene, hexadecanoic acid, 9-octadecenoic acid, ergosterol and hexadecanoic acid, ethyl ester. Trichoderma asperellum significantly increased plant emergence and reduced root rot caused by Fusarium solani in dry bean grown under glasshouse and field trials. Further, plant biomass and dry bean yield were higher in T. asperellum-treated plants than in control plants. Trichoderma asperellum was highly effective, through various mechanisms, against Fusarium strains especially F. solani which causes root rot in dry bean. © 2023 Society of Chemical Industry.

Effect of host genotype on biocontrol of white root rot in Pyrus communis L. rootstocks by Trichoderma harzianum and Bacillus spp.

AbstractA collection of Bacillus and Trichoderma isolates from Iran was investigated for the biological control of pear white root rot caused by Rosellinia necatrix. Among the isolates, B. amyloliquefaciens AP4, B. siamensis AP8 and T. harzianum T20a were selected based on their growth inhibition of R. necatrix in dual cultures, as well as by volatiles, diffusible extracts and culture filtrates. Four pear rootstocks (Pyrodwarf, OHF40, OHF60 and Williams) were assessed for white rot in the greenhouse following soil amendment with the three isolates. For OHF40 rootstock, none of the three isolates significantly reduced disease severity, whereas all three isolates significantly reduced disease severity for OHF69 rootstock. For Pyrodwarf rootstock, only T. harzianum T20a and B. amyloliquefaciens AP4 significantly reduced root rot, but all three isolates significantly reduced leaf fall. For Williams rootstock, all three isolates significantly reduced root rot, but only T. harzianum T20a significantly reduced leaf fall. Thus, the effectiveness of both the Bacillus and Trichoderma isolates was highly dependent upon the pear genotype. The lowest levels of white rot symptoms were observed in the Williams‐T. harzianum T20a interaction resulting in root rot severity of 46.6% and leaf fall of 4.7% at 70 dpi. While the effect of plant genotype on biocontrol activity has been reported frequently for Trichoderma, this is one of the first to report such an effect with a Bacillus biocontrol agent. Both Bacillus and Trichoderma can be effective biocontrol agents of pear white rot, but the plant genotype can have a major impact on their effectiveness.

Synergistic benefits of Funneliformis mosseae and Bacillus paramycoides: Enhancing soil health and soybean tolerance to root rot disease

To explore the response of soil metabolite composition to soybean disease, the effect of the combined inoculation of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria on soybean root rot caused by Fusarium oxysporum was studied. A factorial completely randomized design with three factors (AMF, Bacillus. paramycoides, and rot disease stress) was conducted, and eight treatments, including normal groups and stress groups, were performed using pot experiments. GC‒MS and enzymatic assays were used to evaluate the soil factors and soybean growth indicators. The results showed that there were significant differences in the composition of metabolites among the different treatment groups, and 23 metabolites were significantly related to soybean biomass. The combined inoculation of Funneliformis mosseae and Bacillus paramycoides resulted in a significant reduction in harmful soil metabolites associated with root rot disease, such as ethylbenzene and styrene. This reduction in metabolites contributed to improving soil health, as evidenced by enhanced soybean defence enzyme activities and microbial activity, and β-1,3-glucanase, chitinase and phenylalanine ammonia-lyase activities were improved to alleviate plant rhizosphere stress. Furthermore, soybean plants inoculated with the synergistic treatments exhibited reduced root rot disease severity and improved growth indicators compared to control plants. Plant height, root dry weight (RDW), and shoot and root fresh weight (SRFW) were improved by 4.18–53.79%, and the AM fungal colonization rate was also improved under stress. The synergistic application of Funneliformis mosseae and Bacillus paramycoides can effectively enhance soil health by inhibiting the production of harmful soil metabolites and improving soybean tolerance to root rot disease. This approach holds promise for the sustainable management of soil-borne diseases in soybean cultivation.

The Effect of Tomato Cultivar on Pythium Root Rot and Efficacy of Biopesticides

Barriers to broad commercial use of biopesticides include inconsistent efficacy, which can be influenced by plant species, soil type, and production system. Few studies have evaluated the effect of plant cultivar on the efficacy of commercial biopesticides to suppress disease under greenhouse production conditions. The objective of this study was to evaluate the effect of tomato cultivar on Pythium root rot and the efficacy of commercially available microbial biopesticides (Rootshield WP and Cease). Under low to moderate disease, plants treated with Rootshield had lower Pythium root rot severity compared with the control, and this efficacy was influenced by cultivar. The tomato cultivars ‘Ailsa Craig’, ‘Glamour’, and ‘Maxifort’ had up to 75% less disease when treated with Rootshield compared with the water control. This effect was not observed on cultivar ‘Trust’, a scion cultivar used in greenhouse vegetable production. Cease had no effect on Pythium root rot severity. The aboveground dried biomass of plants treated with Rootshield was lower for tomato cultivars Trust and Glamour. This research suggests that cultivar can explain some of the variability of biopesticide efficacy in reducing root rot disease. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Residual Effects of Lablab Green Manure on Root Rot Pathogens and Performance of Common Bean (Phaseolus Vulgaris L)

Organic manures often have considerable residual effect on the subsequent crops in the soil. Residual effects of lablab green manure on root rot pathogens and bean crop establishment was evaluated by conducting field experiments at two sites with varying soil fertility in Nandi South. Common bean varieties KK8 and GLP2 seeds were planted on plots previously treated with different soil amendments. Soil samples were collected before planting and six weeks after emergence to determine the populations of root rot pathogens. Throughout the experiment, data was collected on crop emergence, plant stand, root rot incidence and severity, as well as crop yield. There was increase in crop emergence by 40% for GLP2 and 19% for KK8 with corresponding 7% reduction in root rot incidence in plots previously treated with lablab green manure. There was varitions in the population of root rot pathogens between the two studies, with Kapkerer exhibiting a higher pathogen population compared to Koibem. The primary root rot pathogens isolated and identified were F. solani, F. oxysporum and Pythium ultimum. F. solani and F. oxysporum were the most dominant species isolated in over 90% plant and soil samples. Residual plots treated with lablab green manure recorded a substantial in yield with an impressive increase of 22% when compared to other treatments. Correlation analysis established that disease incidence, and severity was negatively correlated with yield while plant stand was positively correlated with yield. Our research highlights the long-term benefits of lablab green manure as an organic soil amendment, showcasing its ability to improve crop emergence, reduce root rot incidence, and boost overall crop yield. This knowledge can guide farmers in optimizing their agricultural practices for increased productivity and sustainable soil health.

Management of diseases and insect-pests of French bean in Northwestern Indian Himalayan region using integrated approaches

French bean (Phaseolus vulgaris L.) production is adversely affected by many pathogens and insect-pests worldwide. In the present investigation, effect of different bio-fortified composts, organic amendments, botanicals and pesticides were evaluated against diseases and insect- pests of french bean. The results showed that seed treatment and drenching with Trichoderma harzianum strain 11, followed by soil application of fortified farmyard manure resulted in the lowest root rot incidence, highest germination, vigour and yield in french bean. In another set of experiment, soil incorporation of Parthenium hysterophorus, Urtica dioicaandLantana camarawere found to reduce root rot incidence with high germination and pod yield. Among the bioproducts and botanicals tested, foliar spray of cow dung extract (50%) reduced angular leaf spot, rust and bacterial blight severity by 51, 69 and 25 per cent, respectively. Among the fungicides, foliar application of azoxystrobin 23 SC (0.1%) and difenoconazole 25EC (0.025%), also reduced angular leaf spot and rust severity by 93 and 90 per cent, respectively. Among different insect pest management strategies under field conditions, cartap hydrochloride and batain seed extract registered low sucking bug (Chauliops choprai) population. Integrated approaches including bio-agents, botanicals along with chemicals for managing these diseases and insect-pests were found appropriate options. Out of six different IPM modules evaluated, seed treatment with carbendazim along with foliar spray of 0.1% azoxystrobin and cartap hydrochloride resulted in lowest root rot, rust, angular leaf spot, bacterial blight and Chaulopsis choprai bug population in French bean.

FoMC69 Gene in Fusarium oxysporum f. sp. radicis-lycopersici Is Essential for Pathogenicity by Involving Normal Function of Chlamydospores.

Fusarium oxysporum f. sp. radicis-lycopersici (Forl) causes crown and root rot disease in tomato, effecting severe economic losses. However, research on the pathogenicity genes and infection strategy of Forl is limited compared to that on F. oxysporum f. sp. lycopersici (Fol). In this study, we characterized FoMC69 gene in Forl as a homolog of MC69 required for pathogenicity in rice blast pathogen-Magnaporthe oryzae. Gene expression analysis revealed that FoMC69 expressionin Forl is higher than that in Folin planta. FoMC69-knockout mutant of Forl had significantly reduced root rot symptoms compared to the wild-type strain, and full pathogenicity was restored by complementation. By contrast, ΔFoMC69 mutant of Fol presented the same symptoms as the wild type, suggesting that FoMC69 of Forl, but not of Fol, was essential for full virulence in tomato plants. Morphological differences between the Forl and ΔFoMC69 in the roots were observed by fluorescent labeling using WGA-FITC. Chlamydospores of the ΔFoMC69 mutant of Forlcontinuously increased during infection and were three times higher than that of the wild type at 21 days post-inoculation. These observations suggest that FoMC69 of Forl is required for virulence to tomato plants by involving the normal development and germination of chlamydospores.

Root-Associated Microbiomes of Panax notoginseng under the Combined Effect of Plant Development and Alpinia officinarum Hance Essential Oil.

Essential oils (EOs) have been proposed as an alternative to conventional pesticides to inhibit fungal pathogens. However, the application of EOs is considerably limited due to their highly volatile nature and unpredictable effects on other microbes. In our study, the composition of bacterial and fungal communities from the rhizosphere soil of P. notoginseng under four treatment levels of Alpinia officinarum Hance EO was characterized over several growth stages. Leaf weight varied dramatically among the four EO treatment levels after four months of growth, and the disease index at a low concentration (0.14 mg/g) of EO addition was the lowest among the P. notoginseng growth stages. The content of monomeric saponins was elevated when EO was added. Bacterial and fungal diversity in the absence of plants showed a decreasing trend with increasing levels of EO. Bacterial diversity recovery was more correlated with plant growth than was fungal diversity recovery. Compared with the control (no EO addition), a low concentration of EO significantly accumulated Actinomycota, including Acidothermus, Blastococcus, Catenulispora, Conexibacter, Rhodococcus, and Sinomonas, after one month of plant-microbial interaction. Overall, the results showed that both the plant growth stage and EOs drive changes in the microbial community composition in the rhizosphere of P. notoginseng. Plant development status had a stronger influence on bacterial diversity than on fungal diversity. EO had a more significant effect on fungal community composition, increasing the dominance of Ascomycota when EO concentration was increased. Under the interaction of P. notoginseng growth and EO, a large number of bacterial genera that have been described as plant growth-promoting rhizobacteria (PGPR) responded positively to low concentrations of EO application, suggesting that EO may recruit beneficial microbes in the root zone to cope with pathogens and reduce root rot disease. These results offer novel insights into the relationship between EO application, altered microbial communities in the plant roots, plant growth stage, and disease occurrence.

Changes in the Density and Composition of Rhizosphere Pathogenic Fusarium and Beneficial Trichoderma Contributing to Reduced Root Rot of Intercropped Soybean.

The dynamic of soil-borne disease is closely related to the rhizosphere microbial communities. Maize–soybean relay strip intercropping has been shown to significantly control the type of soybean root rot that tends to occur in monoculture. However, it is still unknown whether the rhizosphere microbial community participates in the regulation of intercropped soybean root rot. In this study, rhizosphere Fusarium and Trichoderma communities were compared in either healthy or root-rotted rhizosphere soil from monocultured and intercropped soybean, and our results showed the abundance of rhizosphere Fusarium in intercropping was remarkably different from monoculture. Of four species identified, F. oxysporum was the most aggressive and more frequently isolated in diseased soil of monoculture. In contrast, Trichoderma was largely accumulated in healthy rhizosphere soil of intercropping rather than monoculture. T. harzianum dramatically increased in the rhizosphere of intercropping, while T. virens and T. afroharzianum also exhibited distinct isolation frequency. For the antagonism test in vitro, Trichoderma strains had antagonistic effects on F. oxysporum with the percentage of mycelial inhibition ranging from 50.59–92.94%, and they displayed good mycoparasitic abilities against F. oxysporum through coiling around and entering into the hyphae, expanding along the cell–cell lumen and even dissolving cell walls of the target fungus. These results indicate maize–soybean relay strip intercropping significantly increases the density and composition proportion of beneficial Trichoderma to antagonize the pathogenic Fusarium species in rhizosphere, thus potentially contributing to the suppression of soybean root rot under the intercropping.

Application of composts and potassium sulphate on root rot incidence, morphological growth, yield components, oil content and constitutes of marjoram plants (Majorana hortensis L.)

Isolation of root rot tissue of diseased marjoram plants, yielded isolates fungal genera of Fusarium spp. and Rhizoctonia solani. Isolates of F. monoliforme and F. oxysporum, causing the highest root rot percentage and disease severity of marjoram plants in pot experiment. In the field, soil amendement with either composts of sugarcane bagasse, soybean straw and rice straw and in combination with potassium sulphate at (50 or 75 kg/feddan.). Results obtained indicated that, application of rice straw compost in combination with potassium sulphate (K2O) at 75 kg was the best treatment reduced root rot incidence of marjoram plants and highly significantly increased, plant height, fresh and dry weigh, yield components, content and percentage of essential oil as well in volatile oil high percentage of terpinene -4-ol (42.9%). Meanwhile, the high percentage of linalyl acetate (34.6%) in the application of (K2O) at 75 kg/feddan combined with soybean compost and carvacrol (32.3%) in the application of (K2O) at 75 kg/feddan. So, integration application of composts with (K2O) could be used as alternative strategies to fungicides for controlling root rot disease in marjoram, enhanching plant growth, yield components and constitutes of essential oil.

Response of faba bean to intercropping, biological and chemical control against broomrape and root rot diseases

Multispecies cropping systems contribute to sustainable agriculture with multiple ecosystem services. Effects of intercropping of various crops with faba beans on growth and yield parameters and disease severity of root rot, damping off and broomrape were investigated. This study was implemented in the laboratory, greenhouse and field to investigate the effect of the intercropping systems (fenugreek + faba bean, lupine + faba bean, garlic + faba bean and sole faba bean). The intercropping systems were combined with the application of arbuscular mycorrhiza fungi (AMF) and yeast as bio-control agents, compared to chemical application of herbicides (Glyphosate) and fungicides (Rizolex-T50), to control rot root diseases and broomrape weeds, Orobanche spp., of faba bean plants in vivo and under the naturally infested field. In vitro, yeast and Rizolex-T50 significantly inhibited mycelial growth of root pathogenic fungi. Intercropping with garlic and/or application of Rizolex-T, significantly decreased the incidence and disease index of root rot and damping-off diseases, meanwhile increased percentage of survival plants. In vivo, intercropping with fenugreek and/or application of Glyphosate, significantly reduced the number/weight of spikes/plot of broomrapes. Intercropping with fenugreek combined with AMF application promoted crop growth and significantly increased yield components. The AMF enhanced seed yield/ha when applied to the intercropping of faba bean + fenugreek and faba bean + garlic, showing the highest seed yield/ha with 3.722 and 3.568 ton/ha, respectively. Intercropping of faba bean with garlic integrated with AMF revealed the highest values of LER, 2.45, and net return, 2341 US$/ha. Our results suggested that using faba bean–garlic intercrop along with AMF inoculation can reduce root rot disease, damping off and broomrapes, as well as enhance the profitability of Egyptian farmer and sustainable production.

Combined Effects of Compost and Trichoderma spp. on Reducing Damping-off and Root Rot Diseases of Lentil Plants

Dual treatments of compost and Trichoderma spp. to control damping-off and root rot diseases of lentil were investigated.The obtained results showed that T. harzianum and T. viride were suppressive against lentil pathogen (R. solani). Likewise, both types of compost showed suppression on pathogen at 50%. The microbial population in the two composts was determined, where Com 2 showed the higher population of the recovered microbial load than Com1. Under greenhouse and field conditions, application of Trichoderma spp. and both composts individually or in combination significantly reduced the percentage of damping-off and root rot diseases of lentil caused by R. solani and increased plant survival rate of lentil compared to the infected control. It has been observed that a combined inoculation of Trichoderma spp. and both types of compost significantly increased the plant height, number of nodules and crop parameters, i.e., number of pods, number of seeds, weight of seeds as well as protein content.

Increasing the dose of fungicide in the seed treatment of soybean can reduce root rot caused by two species of Globisporangium

In Brazil, there are some commercial products composed of metalaxyl-M that can be used as seed treatment of soybean. Metalaxyl-M is a fungicide with efficacy against oomycetes, however, the concentrations and recommended doses of commercial products are not very effective. The objective of this study was to investigate the effect of increasing the dose of commercial products composed of metalaxyl-M for controlling root rot of soybean caused by two species of Globisporangium (G. irregulare and G. sporangiiferum var. ultimum) The treatments were arranged in a factorial scheme of 3 fungicides (Apron, Maxim Advanced and Maxim Quattro) x 7 doses (0.000, 0.003, 0.006, 0.012, 0.018, 0.024, 0.030 mg of metalaxyl-M per seed) x 2 soybean cultivars (‘DM57i52’ and ‘NEO530’). Separate experiments were conducted for each species of Globisporangium. There was a significant effect of the doses on the reduction of root rot severity for both soybean cultivars. The response of root rot severity according to the doses followed either logistic or Weibull regression models. The effective concentrations of metalaxyl-M that reduced 50%, 70% and 90% of root rot severity for ‘NEO530’ were higher than ‘DM57i52’ independently of the product applied. Thus, it can be concluded that the increase in fungicide dose compared to what is already used in Brazil, can promote greater levels of control of root rot caused by G. ultimum var. sporangiiferum and G. irregulare in soybean.

English

Soybean root rot is a worldwide soil-borne fungal disease threatening soybean production, causing huge losses in yield and quality of soybean. Fusarium species are well recognized as the important causal agent of Fusarium root rot. To screen the beneficial Bacillus strains with capability of suppressing soybean root rot and evaluate the impact of Bacillus combined with biochar against soybean root rot, a pot experiment was conducted with different treatments. In this study, as potential biological control measures, antagonistic Bacillus isolates and different types of biochar were added to soil separately and excellent antagonistic strains mixed with bamboo biochar were applied to the soil. The results showed that seven Bacillus strains promoted the growth of soybean seedlings and reduced root rot severity by 33 to 61%. Bacillus amylolique faciens NH2 was associated with the lowest incidence of soybean root rot, indicating its bio-control potential. The value of plant height, root length and plant dry weight of soybean in the sterilized soil mixed with biochar separately treatment were superior to those of soybean in the inoculated with pathogen treatment, especially the bamboo biochar treatment reduced soybean root rot caused by Fusarium significantly and which bio-control efficacy was 77.41%. The soybean plants shoot and root dry weights in the biochar mixed B. amylolique faciens NH2 or B. subtilis DBK treatments were increased by17.1, 10.7% and 19.51, 19.64%, respectively, which were significantly higher than those of the inoculated pathogen treatment. Compared to antagonistic strain or biochar individual treatments, the disease control efficiency on soybean root rot was up to 64.86% in NH2 strain mixed with bamboo biochar treatment, which reduced root rot severity significantly and showed a synergistic effect. These results suggest that antagonistic Bacillus strains mixed with biochar can be used as an effective alternative in managing soybean root rot. © 2021 Friends Science Publishers