Control Of Root Rot Disease Research Articles

Inoculation with Penicillium citrinum aids ginseng in resisting Fusarium oxysporum by regulating the root and rhizosphere microbial communities

Ginseng root rot disease caused by Fusarium oxysporum severely decreases root yield and quality, causing huge economic losses. Biological control is safe, environmentally friendly and sustainable. The results from bananas, sunflowers and chickpeas showed that Penicillium citrinum could control root diseases. However, its potential to control root rot disease of the medicinal plant is unclear. Here, the effects of P. citrinum YW322 isolated from ginseng rhizosphere soil on controlling root rot disease of ginseng were evaluated using the pot experiment. Four treatments were set up: no inoculation (CK), P. citrinum inoculation (PC), F. oxysporum inoculation (FO) and mixed inoculation of P. citrinum and F. oxysporum (PCFO). The results showed that the PC treatment did not affect ginseng growth when compared with the CK treatment. The plants in FO grew more slowly and rotted more severely. Distinct from FO, the ginseng plants in the PCFO treatment all grew similarly to CK. Plate confrontation experiments showed that P. citrinum YW322 inhibited the mycelium growth of F. oxysporum YFW32 by 95.75%. After 7 days of cultivation, the filtrate secreted nonvolatile inhibitory substances with 58.82% inhibition. The results from high-throughput sequencing showed that the structure of the bacterial community in ginseng roots and the fungal community in rhizosphere soil in the PCFO treatment were significantly different compared to the FO treatment (p < 0.05). Compared with FO, the abundance of Clostridium was significantly suppressed in the ginseng roots of PCFO treatment (93.5% reduction) (p < 0.05); significant enrichment of fungi such as Mortierella, Trichoderma and Penicillium was observed in ginseng rhizosphere soil in the PCFO treatment (8.26%, 17.44% and 2.80% increase in relative abundance, respectively). The relative abundance of the pathogenic fungus Fusarium decreased 31.85% compared with FO (p < 0.05). Soil physicochemical analysis showed that compared to the FO treatment, the soil pH and S-CAT activity in the PCFO treatment significantly increased (p < 0.05). Therefore, P. citrinum has potential to control ginseng root rot disease by directly inhibiting the growth of F. oxysporum and regulating the community structure of root bacteria and rhizosphere fungi to help ginseng resist F. oxysporum.

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.

A simplified synthetic community rescues Astragalus mongholicus from root rot disease by activating plant-induced systemic resistance

BackgroundPlant health and growth are negatively affected by pathogen invasion; however, plants can dynamically modulate their rhizosphere microbiome and adapt to such biotic stresses. Although plant-recruited protective microbes can be assembled into synthetic communities for application in the control of plant disease, rhizosphere microbial communities commonly contain some taxa at low abundance. The roles of low-abundance microbes in synthetic communities remain unclear; it is also unclear whether all the microbes enriched by plants can enhance host adaptation to the environment. Here, we assembled a synthetic community with a disease resistance function based on differential analysis of root-associated bacterial community composition. We further simplified the synthetic community and investigated the roles of low-abundance bacteria in the control of Astragalus mongholicus root rot disease by a simple synthetic community.ResultsFusarium oxysporum infection reduced bacterial Shannon diversity and significantly affected the bacterial community composition in the rhizosphere and roots of Astragalus mongholicus. Under fungal pathogen challenge, Astragalus mongholicus recruited some beneficial bacteria such as Stenotrophomonas, Achromobacter, Pseudomonas, and Flavobacterium to the rhizosphere and roots. We constructed a disease-resistant bacterial community containing 10 high- and three low-abundance bacteria enriched in diseased roots. After the joint selection of plants and pathogens, the complex synthetic community was further simplified into a four-species community composed of three high-abundance bacteria (Stenotrophomonas sp., Rhizobium sp., Ochrobactrum sp.) and one low-abundance bacterium (Advenella sp.). Notably, a simple community containing these four strains and a thirteen-species community had similar effects on the control root rot disease. Furthermore, the simple community protected plants via a synergistic effect of highly abundant bacteria inhibiting fungal pathogen growth and less abundant bacteria activating plant-induced systemic resistance.ConclusionsOur findings suggest that bacteria with low abundance play an important role in synthetic communities and that only a few bacterial taxa enriched in diseased roots are associated with disease resistance. Therefore, the construction and simplification of synthetic communities found in the present study could be a strategy employed by plants to adapt to environmental stress.-VujMZjCpFzTumqS8Rf9nHVideo abstract

Associated SNPs, Heritabilities, Trait Correlations, and Genomic Breeding Values for Resistance in Snap Beans (Phaseolus vulgaris L.) to Root Rot Caused by Fusarium solani (Mart.) f. sp. phaseoli (Burkholder)

Root rot is a major constraint to snap bean (Phaseolus vulgaris) production in the United States and around the world. Genetic resistance is needed to effectively control root rot disease because cultural control methods are ineffective, and the pathogen will be present at the end of one season of production on previously clean land. A diversity panel of 149 snap bean pure lines was evaluated for resistance to Fusarium root rot in Oregon. Morphological traits potentially associated with root rot resistance, such as aboveground biomass, adventitious roots, taproot diameter, basal root diameter, deepest root angle, shallowest root angle, root angle average, root angle difference, and root angle geometric mean were evaluated and correlated to disease severity. A genome wide association study (GWAS) using the Fixed and random model Circulating Probability Unification (FarmCPU) statistical method, identified five associated single nucleotide polymorphisms (SNPs) for disease severity and two SNPs for biomass. The SNPs were found on Pv03, Pv07, Pv08, Pv10, and Pv11. One candidate gene for disease reaction near a SNP on Pv03 codes for a peroxidase, and two candidates associated with biomass SNPs were a 2-alkenal reductase gene cluster on Pv10 and a Pentatricopeptide repeat domain on Pv11. Bean lines utilized in the study were ranked by genomic estimated breeding values (GEBV) for disease severity, biomass, and the root architecture traits, and the observed and predicted values had high to moderate correlations. Cross validation of genomic predictions showed slightly lower correlational accuracy. Bean lines with the highest GEBV were among the most resistant, but did not necessarily rank at the very top numerically. This study provides information on the relationship of root architecture traits to root rot disease reaction. Snap bean lines with genetic merit for genomic selection were identified and may be utilized in future breeding efforts.

Essential Oil of Foeniculum vulgare Mill. as a Green Fungicide and Defense-Inducing Agent against Fusarium Root Rot Disease in Vicia faba L.

Simple SummaryPlant extracts, including essential oils, are a viable alternative method for controlling plant diseases. This work deals with the exploitation of fennel seed essential oil (FSEO) to inhibit Fusarium solani and control Fusarium root rot disease in Vicai faba. In vitro FSEO inhibited mycelium growth by up to 80% at 400 µL/mL of FSEO. In vivo, the protective effects against Fusarium root rot disease were recorded when FSEO was applied to Vicia faba seeds. The FSEO reduced the disease severity from 98% in plants grown in infested soil with Fusarium solani to 60.1% in plants that previously had their seeds treated with FSEO. GC-MS spectrometry analyses showed that the major chemical components in the essential oil were D-limonene, menthol, estragole and 2-decenal. Applications of the essential oil resulted in increased total phenolic and flavonoid contents in leaves compared with untreated inoculated (control) plants. The defense-related genes, such as defensin and chitinase, were differentially expressed. This study revealed that the essential oil of fennel seed was effective as a control agent against Fusarium root rot in broad beans.Fusarium solani, the causative agent of root rot disease is one of the major constraints of faba bean (Vicia faba L.) yield worldwide. Essential oils have become excellent plant growth stimulators besides their antifungal properties. Foeniculum vulgare Mill. (fennel) is a familiar medicinal plant that has inhibitory effects against phytopathogenic fungi. Herein, different concentrations of fennel seed essential oil (FSEO) (12.5, 25, 50, 100, 200 and 400 μL/mL) were examined against F. solani KHA10 (accession number MW444555) isolated from rotted roots of faba bean in vitro and in vivo. The chemical composition of FSEO, through gas chromatography/mass spectroscopy, revealed 10 major compounds. In vitro, FSEO inhibited F. solani with a minimum inhibitory concentration (MIC) of 25 µL/mL. In vivo, FSEO suppressed Fusarium root rot disease in Vicia faba L. by decreasing the disease severity (61.2%) and disease incidence (50%), and acted as protective agent (32.5%) of Vicia faba L. Improvements in morphological and biochemical parameters were recorded in FSEO-treated faba seeds. Moreover, the expression level of the defense-related genes defensin and chitinase was noticeably enhanced in treated plants. This study suggested using FSEO as a promising antifungal agent against F. solani not only to control root rot disease but also to enhance plant growth and activate plant defense.

Synergistic effect of growth-promoting microorganisms on bio-control of Fusarium oxysporum f. sp. pisi, growth, yield, physiological and anatomical characteristics of pea plants

Fusarium root rot caused by Fusarium oxysporum is an aggressive disease-causing damping-off, root rot, and vascular wilt in all peas growing fields. The disease can cause 100% yield losses under favorable conditions. The present study aims to control Fusarium root rot using Trichoderma harzianum, Pseudomonas fluorescens, and arbuscular mycorrhizal fungi, singly or in combinations. The results showed that all treatments significantly enhanced not only the plant growth, total phenol, activities of antioxidant enzymes, but also, the yield and seed quality. Several changes in the anatomical, physiological, and characteristics of the treated plants were also recorded. Compared to the untreated control treatment, under greenhouse conditions, the maximum reduction of the disease severity (80%) was achieved by the synergistic triple treatment consists of arbuscular mycorrhizal fungi, Trichoderma harzianum, and Pseudomonas fluorescens, as they gave the best growth and yield parameters. The same combination showed the highest activity of the antioxidant enzyme peroxidase (57.1%), as well as the highest total phenol content (117.7%), over the control. The synergistic triple increased the contents of protein (64.6%), total soluble sugars (48.5%), and total carbohydrate (24.8%) in seeds of pea compared with the control. The synergistic triple treatment led to an increase in the thickness of the root section (25%), the thickness of the cortex (24.8%), the thickness of the vascular cylinder (31.5%), and the diameter of the xylem vessels (81.5%) of the root. Based on their efficiency and eco-safety, this synergistic triple might be very effective for controlling root rot disease of pea caused by F. oxysporum, as well as improve the growth, yield, and seed quality.

Field evaluation of Rot-fix for management of root rot disease of mulberry (Morus sp.)

Mulberry is cultivated throughout India as a host plant of silkworm (Bombyx mori L.) reared for commercial production of silk. The quality of silk produced depends largely on the quality of leaf fed to silkworm. Various mulberry diseases limit quality and quantity of silk production affecting the economic return to the farmers. Among these, root rot caused by a group of fungi is a severe threat for mulberry leaf production, especially in southern states of India due to large scale mortality and enormous crop loss. Though many fungi are isolated from the infected root, Fusarium solani is the one frequently found associated with the disease. Chemical control with fungicides is not advisable due the environmental concern and toxicity to the soil and silkworm. Thus, recently a broad spectrum environment friendly formulation viz., Rotfix has been developed by the Central Sericultural Research &amp; Training Institute, Mysore and recommended after limited on-farm and field trials. However its efficiency has not been evaluated at the farmers’ level in large scale. The present study has been conducted to evaluate the effect of Rot-fix in large scale in four southern states of India. The Rot-fix has been applied to the infected plants and their recovery has been studied. There was a high recovery (86.76-91.96%) of the infected plants after application of Rot-fix. Though the leaf yield was significantly (P&lt;0.01) lower (2.48%) in the recovered plants in first crop, by the second crop the plants were recovered completely and started giving yield the statistically on par with untreated healthy plants. The study therefore recommends the use of Rot-fix in large scale for control of root rot disease of mulberry.

Effects and Mechanisms of Symbiotic Microbial Combination Agents to Control Tomato Fusarium Crown and Root Rot Disease.

This study evaluated the effects and underlying mechanisms of different combinations of plant symbiotic microbes, comprising arbuscular mycorrhizal fungi (AMF), plant growth-promoting rhizobacteria (PGPR), and Trichoderma spp., on tomato Fusarium crown and root rot (TFCRR) resistance. A total of 54 treatments were applied in a greenhouse pot experiment to tomato (Solanum lycopersicum) seedlings inoculated with or without Funneliformis mosseae (Fm), Rhizophagus intraradices (Ri), Trichoderma virens l40012 (Tv), Trichoderma harzianum l40015 (Th), Bacillus subtilis PS1-3 (Bs), Pseudomonas fluorescens PS2-6 (Pf), and Fusarium oxysporum f. sp. radicis-lycopersici (Fo). The symbioses on the tomato root system were well developed, and the composite symbiont generated by AMF + Trichoderma spp. was observed for the first time. Compared with other treatments, Ri + Bs + Tv and Fm + Pf + Tv stimulated the greatest improvements in tomato growth and yield. The combination Ri + Pf + Th + Fo resulted in the strongest biocontrol effects on TFCRR, followed by the treatments Th + Pf + Fo and Ri + Th + Fo. Compared with the Fo treatment, most inoculation treatments improved photosynthetic performance and significantly increased defense enzyme activity in tomato plants, of which the treatment Ri + Pf + Th + Fo showed the highest enzyme activity. Metabolome analysis detected changes in a total of 1,266 metabolites. The number of up-regulated metabolites in tomato plants inoculated with Ri + Pf + Th and Ri + Pf + Th + Fo exceeded that of the Fo treatment, whereas the number of down-regulated metabolites showed the opposite trend. It is concluded that AMF + Trichoderma + PGPR is the most effective combination to promote resistance to TFCRR in tomato. The up-regulation and down-regulation of metabolites regulated by symbiotic microbial genes may be an important mechanism by which root symbiotic microorganisms promote plant growth, increase yield, and improve disease resistance.

Protective and Curative Effects of Trichoderma asperelloides Ta41 on Tomato Root Rot Caused by Rhizoctonia solani Rs33

Two molecularly identified tomato isolates, Trichoderma asperelloides Ta41 and Rhizoctonia solani Rs33, were characterized and antagonistically evaluated. The dual culture technique showed that Ta41 had a high antagonistic activity of 83.33%, while a light microscope bioassay demonstrated that the Ta41 isolate over-parasitized the pathogen completely. Under greenhouse conditions, the application of Ta41 was able to promote tomato plant growth and had a significant increase in plant height, root length, and shoot fresh, shoot dry, root fresh, and root dry weight. It also improved chlorophyll content and total phenol content significantly, both in protective and in curative treatments. The protective treatment assay exhibited the lowest disease index (16.00%), while the curative treatment showed a disease index of 33.33%. At 20 days post-inoculation, significant increases in the relative expression levels of four defense-related genes (PR-1, PR-2, PR-3, and CHS) were observed in all Ta41-treated plants when compared with the non-treated plants. Interestingly, the plants treated with Ta41 alone showed the highest expression, with relative transcriptional levels of CHS, PR-3, PR-1, and PR-2 that were, compared with the control, 3.91-, 3.13-, 2.94-, and 2.69-fold higher, respectively, and the protective treatment showed relative transcriptional levels that were 3.50-, 3.63-, 2.39-, and 2.27-fold higher, respectively. Consequently, the ability of Ta41 to promote tomato growth, suppress Rs33 growth, and induce systemic resistance supports the incorporation of Ta41 as a potential bioagent for controlling root rot disease and increasing the productivity of crops, including tomatoes.

Bacillus velezensis CE 100 Inhibits Root Rot Diseases (Phytophthora spp.) and Promotes Growth of Japanese Cypress (Chamaecyparis obtusa Endlicher) Seedlings.

Root rot diseases, caused by phytopathogenic oomycetes, Phytophthora spp. cause devastating losses involving forest seedlings, such as Japanese cypress (Chamaecyparis obtusa Endlicher) in Korea. Plant growth-promoting rhizobacteria (PGPR) are a promising strategy to control root rot diseases and promote growth in seedlings. In this study, the potential of Bacillus velezensis CE 100 in controlling Phytophthora root rot diseases and promoting the growth of C. obtusa seedlings was investigated. B. velezensis CE 100 produced β-1,3-glucanase and protease enzymes, which degrade the β-glucan and protein components of phytopathogenic oomycetes cell-wall, causing mycelial growth inhibition of P. boehmeriae, P. cinnamomi, P. drechsleri and P. erythoroseptica by 54.6%, 62.6%, 74.3%, and 73.7%, respectively. The inhibited phytopathogens showed abnormal growth characterized by swelling and deformation of hyphae. B. velezensis CE 100 increased the survival rate of C. obtusa seedlings 2.0-fold and 1.7-fold compared to control, and fertilizer treatment, respectively. Moreover, B. velezensis CE 100 produced indole-3-acetic acid (IAA) up to 183.7 mg/L, resulting in a significant increase in the growth of C. obtusa seedlings compared to control, or chemical fertilizer treatment, respectively. Therefore, this study demonstrates that B. velezensis CE 100 could simultaneously control Phytophthora root rot diseases and enhance growth of C. obtusa seedlings.

Biological Control of Root Rot Disease and Growth Promotion in Fenugreek (Trigonella foenum-graecum L.) Mediated by Microbial Antagonism

PATHOGENIC fungi are among the most serious biotic agents that attack plants and cause considerable losses in crop yield. Therefore, a sincere effort is being made to provide safe and inexpensive ecofriendly innovative approaches for managing plant diseases and reducing the fungicide pressure in our agro-ecosystem. In this study, Bradyrhizobium japonicum Asw1 was successfully used for suppressing the root rot disease of fenugreek (Trigonella foenum-graecum L.) caused by Fusarium solani. Strain Asw1 exhibited significant antifungal activity revealing remarkable antagonistic effect against the pathogen. The results showed that T. foenum-graecum was susceptible to fungal infection which severely affected the growth and metabolite content of the plant. Treatment with strain Asw1 resulted in a sharp reduction of disease incidence from 80 to 13%. Growth attributes, e.g., plant height (cm), number of leaves per plant, fresh and dry weight (g) of treated plants were significantly enhanced. The contents of chlorophylls, proteins, carbohydrates, flavonoids, phenolics and tannins were significantly (P< 0.05) reduced in the infected plants. In the treated plants, protein and carbohydrate contents were not enhanced compared to control. However, the content of total flavonoids was significantly accumulated in the treated plants which might trigger their resistance against fungal infection.

Efficiency of bio-evaporation of Arugula leaves to control root rot disease on cucumber caused by Pythium intermedium in Greenhouse

The efficiency of the Arugula (Eruca vesicaria) leaves extracts against the fungus Pythium intermedium, the root rot disease agent, was evaluated with three concentrations of 2.5, 5, 10 g / kg soil as biofumigation. The fungi around infected root of cucumber plants were isolated and diagnosed from different locations in Baghdad such as Rashidiya, Madaen, Yousifiya and Mahmudiya. The extract of arugula plants significantly reduced the incidence and severity of root rot disease on cucumber plant after 45 days of cultivation compared with control. The highest reduction in incidence and severity of the disease was about 4% and 5% respectively with arugula extract 10 g / kg soil. The study was the first record to evaluate the incidence of P. intermedium on root of cucumber plants in Iraq. Further, all concentrations of arugula extract showed increase on the growth parameters compared with control. In arugula extract 10 g/kg soil the growth parameter such as plant length, leaf length, leaf width, wet weight and dry weight were 35 cm, 5.5 cm, 6 cm, 4 g and 0.28 g respectively. Furthermore, Significant differences in the value of the biological index of arugula plant extract treatments ranging from 2627 to 3433 compared to the treatment of P. intermedium, which was about 1910, while did not differ significantly from the treatment of control with a vital index of 3830.

A pipeline for the genetic improvement of a biological control agent enhances its potential for controlling soil-borne plant pathogens

Use of biopesticides results in a reduction of the worldwide dependence on chemical pesticides, ending in a more sustainable crop protection. For this reason, biological control industry invests in continued research for more effective biocontrol agents (BCAs) using basically two strategies: isolation of new strains from nature or conventional genetic improvement. However, both are highly onerous and time-consuming. Here we show a pipeline for the genetic improvement of fungal BCAs, based on genome shuffling, the most recent and promising non-recombinant DNA technology for the rapid phenotype improvement of microbial strains. The method consisted of the construction of a parent library using mutagenic agents, followed by genome shuffling and high-throughput screening. Sarocladium oryzae BRM 6461, a known cerulenin antifungal producer strain and high biocontrol potential, served as the model fungal BCA. The pipeline aimed to select mutant enhanced strains at least one of these three desirable characteristics: antagonism, UV-B irradiation tolerance and high temperature tolerance. The experiments were conducted in laboratory and green house. After four cycles of genome shuffling we selected the superior S. oryzae GS4-03 strain, showing cerulenin production of 203.3 ± 1.4 µg/mL, 42% higher than the wild-type strain BRM 6461. The GS4-03 strain exhibited good genetic stability for at least five successive subcultivation assays. Antagonism assay showed an increased micelial inhibition of Rhizoctonia solani and Sclerotinia sclerotiorum when using GS4-03 strain compared to the BRM 6461 strain. The bioassays, showed that the superior strain GS4-03 have an increased ability to control root rot (23.4%) and white mold (8.1 times) disease compared to the wild type strain BRM 6461. Assessment of virulence of the superior strain GS4-03 against rice plants showed that improvement procedures did not change the original strain behavior in this subject. Hydrolytic activity of enzymes related to the biocontrol action as chitinase, protease and β-1,3-glucanase did not present statistical difference between GS4-03 and BRM 6461 strains. Results of dual assay culture between GS4-03 and BRM 6461 strains showed that both have different genetic backgrounds, although RAPD and ITS-rDNA tests were not fully efficient to distinguish genetically the strains. Moreover, mutations resulted in S. oryzae strains more tolerant to UV-B irradiation, but with low genetic stability. Our results report for the first time an efficient pipeline for the genetic improvement of fungal BCAs based on genome shuffling.

Isolation and characterization of endophytic bacteria for controlling root rot disease of Chinese jujube.

Fusarium oxysporum is the primary pathogen causing root rot disease that severely affects cultivation of jujube fruit in the Xinjiang province of China. The aim of this study was to identify endophytic bacteria in healthy jujube organs that could effectively suppress F. oxysporum growth. Different plant organs (leaves, twigs and roots) were collected from healthy Chinese jujube cultivated in southern Xinjiang province of China. The endophytic bacterium Brevibacterium halotolerans JZ7 was selected for its strong antagonistic activity and growth-promoting characteristics. Gas-chromatography mass-spectrometry analysis showed that acetoin, 2,3-butanediol and fenretinide were the three dominant volatile organic compounds produced by strain JZ7. Fenretinide strongly suppressed spore germination of F. oxysporum in vitro. Pot experiments showed that strain JZ7 colonized both the roots and rhizosphere soil of Chinese jujube and significantly reduced F. oxysporum level in jujube rhizosphere soil. We demonstrated that B. halotolerans JZ7 can be developed into a biological control agent to combat root rot disease of Chinese jujube in the Xinjiang province of China. The suggested strategy for biological control of jujube root rot disease is fully in accordance with the current principles of sustainability.

A research article on Trichoderma spp: An effective biocontrol agent for management of plant diseases and enhance the sustainability

Trichoderma spp. are free living asexual fungi that are present in all types of agricultural soils, root ecosystem and also in decaying wood. The fungus is also a decomposer of cellulosic waste materials and antagonistic activity showed that it is parasitic on many soil-borne and foliage pathogens viz., bacteria, fungus, virus, nematodes and higher parasitic plants and effectively control collar rot, root rot, foot rot, stem rot, sheath blight, gray mold, damping off, mildew and other disease like nematode causing problems etc. The traditional method (chemical-based pesticides) control plant diseases very effectively and suppress plant pathogens but these are not eco-friendly. Continuous use of agro-chemical and pesticides caused the resistance in pathogens towards these chemicals. It not only develops resistance among pathogens but also causes environmental pollution, this hazardous chemical pollutes water body and pollute our food chain too. It is harming fish and other aquatic lives, beneficial insects like honeybee, predator insects and other non-targeted organisms like plant growth promoting rhizobacteria-fungus (PGPR & PGPF). For overcome with these unsafe methods researchers are searching some other alternative methods that are significantly eco-friendly. Biological control agents, plants extract, crop rotation with potential crop/varieties, repellent plant, natural enemies, PGPR and PGPF are some of the most effective control measure in which, Trichoderma is the most versatile fungus genus that can control and manage phytopathogenic diseases and so increase plant growth. So, this review was summarised that Trichoderma spp. act as effective bio-agent can control many plant pathogenic fungus like Fusarium, Phytophthora, Pythium, Colletotrichum, Fulvia, Rhizoctonia, Rhizopus, Alternaria, Verticillium, and Sclerotinia etc.

Efficiency of Pseudomonas spp.-based formulation for controlling root rot disease of black cumin under greenhouse and field conditions

Black cumin (Nigella sativa) is an important seed spices crop, Fusarium root rot is a serious fungal disease responsible for significant losses worldwide, the present work was planned to study the used of some strains of Pseudomonas spp. to reduce the root rot disease of black cumin caused by Fusarium solani. Three isolates of Pseudomonas spp. were recovered from rhizosphere of black cumin plants and they were identified as Psedomonas fluorescens (PF1, PF2) and P. aeruginosa (PF3). They were tested as formulation and suspension under greenhouse and field conditions against root rot disease to reduce the disease severity. The results show that P. fluorescens (PF1) as a suspension and formulation gave the highest effect in reducing the disease severity (7.70 and 7.73%) also reduce the number of pathogenic fungi than control. All tested bacteria increased seed production than infected control. The laboratory results show that PF1 gave highest amount of siderophores followed by PF3, while P. fluorescens (PF2) show a weak production. Also, all tested bacteria have ability to phosphate solubilization with different degree among them, PF3 has highly ablitity to phosphate solubiization followed by other isolates. It could be control of F. solani the causal of root rot under greenhouse and field condition with this bioagents and could recommend using these isolates to control of root rot diseases of N. sativa under Assiut conditions.

Potential activities of Bacillus simplex as a biocontrol agent against root rot of Nigella sativa caused by Fusarium camptoceras

This study aimed to investigate the impact of two isolates of Bacillus simplex (PHYB1 and PHYB9) for controlling the root rot disease of black cumin (Nigella sativa) caused by Fusarium camptoceras (PHYF1) under greenhouse and field conditions at Assiut Governorate, Egypt. The highest reduction percentage of infection (22.5%) was recorded by the treatment of PHYB1 as suspension than the control (60%). Both isolates of Bacillus spp. provided the root and foliar dry weight under greenhouse and seed production in the field. The results showed that the isolate PHYB1 as a formulation gave the highest impact in the root dry weight (0.28 g/plant), followed by PHYB9 (0.22 g/plant), with insignificant difference between them. PHYB9 suspension also provided the highest seed production (27.97 g/plant), whereas PHYB9 as a formulation gave the lowest (24.08 g/plant). Studies on the interaction between Bacillus spp. on F. camptoceras by scanning electron microscope (SEM) revealed that both caused a complete mycoparasitism on the fungal growth. The bacterial growth was seen to adhere and colonize the hyphae, resulting in hyphal tissue maceration. Therefore, the use of both isolates of Bacillus spp. to control root rot disease of black cumin under greenhouse and field conditions can be recommended.

Compatibility of biological control agents with fungicides against root rot diseases of wheat

Root - rot diseases are considered the most serious diseases of wheat in Egypt, causing a considerable loss seed germination, plant stand and grain yield. The present study aims to evaluate the fungicidal activity of four chemical fungicides and two biological control agents. Four fungicides (i.e. triticonazole, carbendazim, carboxin + thiram and metalaxyl M + fludioxonil) and two biological control agents (i.e. Trichoderma harzianum and Bacillus subtilis) were evaluated separately and their compatibility against two pathogenic fungi, Rhizoctonia solani and Fusarium graminearum that causing root rot diseases of wheat. The in vitro studies showed that the fungicidal activity of the tested fungicides against R. solani mycelial growth was descendingly arranged as follows; metalaxyl M + fludioxonil > carbendazim > triticonazole > carboxin + thiram, while it was metalaxyl M + fludioxonil > triticonazole > carbendazim > carboxin + thiram against F. graminearum mycelial growth. In greenhouse trials, the fungicides were applied at 1.5 and 3.0 g kg-1 seeds as seed treatment, while biological control agents were applied at 4.5 and 9.0 x 106 spores mL-1 water as soil treatment. The results showed that all the treatments significantly reduced disease incidence and increased emergence and plant stands and the biological control agents were the inferior treatments. Generally, the most effective treatments for controlling root rot diseases were metalaxyl M + fludioxonil followed by carbendazim, triticonazole, while the lowest were carboxin + thiram, B. subtilis and T. harzianum as compared with the control treatment. Moreover, the results concluded that the efficiency of T. harzianum and B. subtilis in controlling R. solani and F. graminearum was obviously enhanced by their compatibility with low rates of the tested fungicides. In conclusion, the biological strategy which used throughout integrated pest management could be improved by using fungicides at low rates.

Toprak Kökenli Bitki Patojeni Funguslarla Mücadelede Biofumigasyonun Kullanım Olanakları

Fusarium, Rhizoctonia, Sclerotinia, Verticillium, Armillaria ve Rosellinia gibi toprak kökenli bitki patojeni funguslar, birçok bahçe ve tarla ürününde bitki ölümlerine ve verim kayıplarına sebep olan kök çürüklüğü hastalıklarına neden olmaktadır. Kök çürüklüğü hastalıklarının kontrolünde dayanıklı çeşit kullanımı, ürün rotasyonu, solarizasyon, fungisit uygulamaları ve toprak fumigasyonu gibi çeşitli mücadele yöntemleri uygulanmaktadır. Metil bromide ve kloropikrin gibi fumigantlarla yapılan toprak fumigasyonu toprak kökenli fungusların kontrolü için kullanılan en etkili yöntemlerden biridir. Ancak bu kimyasalların çevre ve insan sağlığına olumsuz etkilerinden dolayı dünyada ve ülkemizde kullanımı yasaklanmıştır. Bu nedenle, yeterli hastalık kontrolü sağlayan ve ticari fungisitlerle rekabet edebilen alternatif yöntemlerin araştırılmasına ihtiyaç vardır. Biofumigasyon kimyasal mücadeleye alternatif yöntemler arasında değerlendirilmekte nematodlar, yabancı otlar ve bazı fungusların neden olduğu hastalıkların mücadelesinde oldukça etkili olup, entegre mücadelenin bir parçası olarak kabul edilmektedir. Toprak kökenli fungusların kontrolünde örtücü bitkiler, organik gübre ve biyokatı atıklar biyofumigant olarak değerlendirilmektedir. Bu çalışmada toprak kökenli fungusların kontrolünde biyofumigasyon uygulamaları ve biyofumigantların funguslar üzerindeki etki şekilleri değerlendirilmiştir.

Effect of Brassica crop-based biofumigation on soilborne disease suppression in woody ornamentals

Soilborne diseases are the most economically important problem for ornamental nursery producers in the southeastern United States. The use of cover crops selected based on their biofumigant activity to improve soilborne disease management in woody ornamental production was assessed. Replicated pot bioassays were established as greenhouse trials in sterilized clay loam soil which had pre-existing populations of Rhizoctonia solani or Phytophthora nicotianae. Selected Brassica crops were seeded directly into the soil and flowering cover crops were incorporated 15 cm deep into the same pots and covered with polyethylene for 2 or 4 weeks. Volatile compounds released during the biofumigation process were collected at different time intervals. Soil type and moisture affected ITC release. Hydrangea or viburnum rooted cuttings were grown in the biofumigated (2 or 4 weeks) and non-biofumigated control pots and root rot disease severity was evaluated at the end of each bioassay. Yellow mustard (Sinapis alba, ‘White gold’), turnip (Brassica rapa, ‘Purple top forage’), arugula (Eruca vesicaria ssp. sativa, ‘Astro’), Mighty mustard (B. juncea, ‘Pacific gold’), rape (B. napus, ‘Dwarf essex’), mustard green (B. carinata, ‘Amara’) and brown mustard (B. juncea, ‘Kodiak’) cover crops were effective in suppressing R. solani and P. nicotianae. Similar disease suppression was observed whether biofumigation was performed for 2 or 4 weeks. Phytotoxicity was not observed on viburnum and hydrangea woody ornamental plants after either the 2 or 4 weeks biofumigation period with any of the tested cover crops. Viburnum and hydrangea grown in mustard green-, arugula- and turnip-incorporated soil had significantly higher whole plant and root fresh weights compared with the inoculated, non-biofumigated control plants. Although mustard green and arugula are not used currently as commercial biofumigation cover crops, they also showed promise for controlling soilborne pathogens of woody ornamental plants under greenhouse conditions.