Control Of Wilt Disease Research Articles

Selenium nanoparticles are effective in penetrating pine and causing high oxidative damage to Bursaphelenchus xylophilus in pine wilt disease control.

Research on selenium nanoparticles (SeNPs) in chemical defense and chemotherapy of plants has developed rapidly owing to their high microbial toxicity, environmental safety, and degradability. Pine wilt disease (PWD) threatens pine forests worldwide; however, it is difficult to kill the nematodes (Bursaphelenchus xylophilus) inside the tree that cause PWD using traditional pesticide formulations. SeNPs could be the key to controlling PWD. In this study, approximately 50 nm SeNPs were prepared using a simple and green method, and chitosan was used to increase their biocompatibility and stability. The preparation and characterization results showed that the prepared SeNPs coated with chitosan (SeNPs@CS) were spherical and evenly dispersed. The bioassay results showed that SeNPs@CS had an LC50 of 15.627 mg L-1 against B. xylophilus. In addition, the killing mechanism of SeNPs@CS against B. xylophilus was studied. Confocal microscopy and transmission electron microscopy demonstrated that B. xylophilus were killed by reactive oxygen species, and the penetration of nano-form materials to B. xylophilus was higher than that of non-nano-form materials. To verify the effective penetration of SeNPs in pine tissues, Cy5-labeled SeNPs@CS was observed inside pine needles and branches using frozen sections and confocal microscopy. In addition, the cytotoxicity of SeO2 and SeNPs@CS was tested, and the results showed that the cytotoxicity of SeNPs@CS to MC3T3-E1 cells was reduced. These results show that SeNPs are expected to be used as a new strategy for the control of PWD with oxidative damage and high penetration to B. xylophilus and effective target penetration and biosafety. © 2022 Society of Chemical Industry.

Influences of Serendipita indica and Dictyophorae echinovolvata on the Growth and Fusarium Wilt Disease Resistance of Banana.

Simple SummaryBy using ‘Zhongjiao No.3’ and ‘Zhongjiao No.4’ banana seedlings as plant materials, we investigated the influences of Serendipita indica and bamboo fungus (Dictyophorae echinovolvata) culture substrates on the growth and wilt disease resistance of banana. S. indica colonization significantly enhanced the growth of the two banana cultivars, while banana seedlings grown in nutrient soil containing bamboo fungus culture substrates inoculated with D. echinovolvata showed suppressed growth. Moreover, both S. indica colonization and D. echinovolvata culture substrates addition can alleviate the disease symptoms caused by Fusarium oxysporum f. sp. cubense tropical race 4 (FocTR4), and their combined application showed the best disease resistance enhancement effect. The results obtained in this study can provide a basis for the application of S. indica and bamboo fungus in the prevention and control of banana Fusarium wilt disease in the future.Recently, many control methods have been tried and applied in the Fusarium wilt disease control of banana and have achieved definite progresses. In this study, by using ‘Zhongjiao No.3’ and ‘Zhongjiao No.4’ banana seedlings as materials, the effects of Serendipita indica and bamboo fungus (Dictyophorae echinovolvata) culture substrates on the growth and Fusarium wilt disease resistance of banana were investigated. Results showed that the plant height, leaf length, leaf width, root length and root thickness, aboveground part fresh weight, root fresh weight, and relative chlorophyll content and nitrogen content in leaves of banana seedlings colonized with S. indica were all greater than those of non-colonized controls, while these parameters of banana seedlings grown in nutrient soil containing D. echinovolvata culture substrates were significantly suppressed. Both S. indica non-colonized and colonized seedlings cultivated in nutrient containing 1/4 D. echinovolvata culture substrates showed much milder symptoms compared with those cultivated in normal nutrient soil, indicating that the addition of bamboo fungus substrates to the soil can enhance the Fusarium wilt resistance of banana. The results obtained in this study can provide a basis for the application of S. indica and bamboo fungus in the prevention and control of banana Fusarium wilt disease.

Management of wilt disease caused by Fusarium oxysporum f.sp. Ciceri in chickpea

Field experiment as well as lab experiment were conducted for two years to find out effective fungicides for control of wilt disease in chickpea. Carbendazim+ thiram (1:2) and carbendazim proved to be most effective in inhibiting cent per cent growth of the test fungus at the concentrations of 250 and 500 ppm, respectively followed by thiram (500 ppm) and carboxin + thiram (500 ppm). Next effective fungicides in order were tabuconazole (500 ppm), carboxin + thiram (250 ppm), thiram (500 ppm). In field experiment, all the fungicides as seed treatments reduced the wilt disease incidence significantly over untreated check during both the years. In different treatments, disease incidence varied from 11.00 to 19.67 and 10.63 to 16.70 as against 45.67 and 42.17 percent in check in 2014–15 and 2015–16, respectively. However, seed treatment with carbendazim+ thiram (1:2) @ 2g/kg seed provided the maximum seed germination (82.33 and 80.00 per cent), minimum disease incidence (11.00 and 10.63 per cent) and maximum grain yield (1366.67 and 1366.67 kg/ha) closely followed by carbendazim and thiram during both the years.

Evaluation of indigenous seed treating materials in managing diseases of fennel (Foeniculum vulgare Mill)

The field trial conducted at Agronomy farm, S.K.N. College of Agriculture, Jobner during rabi 2015-16 & 2016-17 in randomized blocked design (RBD), evaluating the efficacy of seed treatments viz., - cow urine (2.5%), asafoetidaheeng (1.2%), castor oil seven (5%), garlic clove extract (5%) - turmeric powder (5%), T6- turmeric extract (5%) and neem oil (5%) in the management of diseases of fennel indicated that all the treatments were found superior over control. The germination per cent was highest in garlic treated plots followed by neem oil treated plots. The neem seed oil treatment followed by garlic treatments recorded the maximum control of wilt diseases. The intensity of alternaria blight and powdery mildew diseases was found least in garlic-treated plots followed by neem and castor oil-treated plants.

Effect of the Nanoparticle Exposures on the Tomato Bacterial Wilt Disease Control by Modulating the Rhizosphere Bacterial Community.

Ralstonia Solanacearum is one of the most infectious soil-borne bacterial plant pathogens, causing tomato bacterial wilt (TBW). Nanotechnology is an emerging area of research, particularly the application of nanoparticles (NPs) as nanopesticides to manage plant disease is gaining attention nowadays. However, the interaction between NPs and rhizosphere bacterial communities remains largely elusive. This study indicated that metal NPs (CuO, ZnO, and FeO) reduced the incidence of bacterial wilt to varying degrees and affected the composition and structure of the rhizosphere bacterial community. The results revealed that the application of metal oxide NPs can improve the morphological and physiological parameters of TBW infected tomato plants. Among all, CuONPs amendments significantly increase the Chao1 and Shannon index. In the early stage (the second week), it significantly reduces the relative abundance of pathogens. However, the relative abundance of beneficial Streptomyces bacteria increased significantly, negatively correlated with the relative abundance of pathogenic bacteria. In addition, the nano-treatment group will enrich some potential beneficial bacteria such as species from Sphingomonadaceae, Rhizobiaceae, etc. In general, our research provides evidence and strategies for preventing and controlling soil-borne disease tomato bacterial wilt with metal oxide NPs.

Evaluation of Some New Generation Fungicides against Pigeonpea (Cajanus cajan (L.) Millsp.) Wilt Causal agent Fusarium udum under in vitro Conditions

Pigeonpea wilt disease caused by Fusarium udum is one of the most devastating soil borne disease. The objective of this investigation was to determine the antifungal activities of fungicides which can be used to control wilt disease of pigeonpea. Among all the fungicides Azoxystrobin+Tebuconazole, Carbendazim, Tebuconazole+Trifloxystrobin, Hexaconazole, Tebuconazole exhibited 100% inhibition at all the concentrations, followed by Azoxystrobin+ Difenconazole which exhibited 92.22%, 94.4%, 94.4% and 100% inhibition at 250 ppm, 500 ppm, 750 ppm and 1000 ppm respectively.

Molecular identification and biological control of Ralstonia solanacearum from wilt of papaya by natural compounds and Bacillus subtilis: An integrated experimental and computational study

Ralstonia solanacearum is a harmful pathogen that causes severe wilt disease in several vegetables. In the present study, we identified R. solanacearum from wilt of papaya by 16S rRNA PCR amplification. Virulence ability of R. solanacearum was determined by amplification of approximately 1500 bp clear band of hrpB gene. Further, in-vitro seed germination assay showed that R. solanacearum reduced the germination rate up to 26.21%, 34% and 33.63% of cucumber, bottle guard and pumpkin seeds, respectively whereas shoot and root growth were also significantly decreased. Moreover, growth inhibition of R. solanacearum was recorded using antibacterial compound from medicinal plant and antagonistic B. subtilis. Petroleum ether root extract of Rauvolfia serpentina showed highest 22 ± 0.04 mm diameter of zone of inhibition where methanolic extract of Cymbopogon citratus and ethanolic extract of Lantana camara exhibited 20 ± 0.06 mm and 20 ± 0.01 mm zone of inhibition against R. solanacearum, respectively. In addition, bioactive compounds of B. subtilis inhibited R. solanacearum growth by generating 17 ± 0.09 mm zone of inhibition. To unveil the inhibition mechanism, we adopted chemical-protein interaction network and molecular docking approaches where we found that, rutin from C. citratus interacts with citrate (Si)-synthase and dihydrolipoyl dehydrogenase of R. solanacearum with binding affinity of −9.7 kcal/mol and −9.5 kcal/mol while quercetin from B. subtillis interacts with the essential protein F0F1 ATP synthase subunit alpha of the R. solancearum with binding affinity of −6.9 kcal/mol and inhibit the growth of R. solanacearum. Our study will give shed light on the development of eco-friendly biological control of wilt disease of papaya.

Mycoparasitic nature of Egyptian Trichoderma isolates and their impact on suppression Fusarium wilt of tomato

BackgroundPlant disease administration is difficult due to the soil-borne nature of the phytopathogens. Biological control of plant disease is a safe mode to avoid the problems related to fungal diseases that affect crops productivity.ResultsTwenty-three Trichoderma isolates were isolated from soil, surrounding healthy tomato roots from different regions in the Egyptian Governorate of Menoufia. Using a dual culture method to test the efficiency of Trichoderma isolates, the most effective isolate identified as Trichoderma atrovirde with percentage inhibition against Fusarium oxysporum f. sp. lycopersici (92.11%) and scanning electron microscope examination documented the mycoparasitic nature of T. atrovirde to F. oxysporum. Treatments with 10% filtrate T. atrovirde improved the growth aspects of tomato plants than the control plants or infected only, as well as the increase in phenol content (15.09 ug. g-1dry weight) and decreased disease incidence percentage (8%) than the plants infected only (60%).ConclusionsThis study clearly demonstrated that T. atrovirde had a significant inhibition against F. oxysporum. Greenhouse assays displayed the protective role of T. atrovirde inoculation directly against pathogen or indirectly related to the defense mechanism in the plant. So, this study recommends using T. atrovirde for biological control of wilt disease in tomato plants.

The use of endophyte fungal isolates in controlling Fusarium oxysporum, the causal agent of wilt disease on chilli (Capsicum annuum)

Fusarium oxysporum as the causal agent of wilt disease infected systemically on the chili plant (Capsicum annuum) and cause a significant loss on its production. To control the pathogenic fungi, we isolated and identified the beneficial fungi from stem, leaf, and fruit tissues of healthy plants. Then, the work tested fungi capability to inhibit the pathogen in vitro and to enter plant tissues. The results of the work indicated that seven fungi isolates consisting of Trichoderma 1, Trichoderma 2, Aspergillus, Fusarium 1, Fusarium 2, Lasiodiplodia 1, and Lasiodiplodia 2 were identified. Trichoderma and Lasiodiplodia were found from leaf and fruit tissues, whereas Aspergillus and Fusarium were isolated from leaf and stem tissues. The inhibition of F. oxysporum by these seven fungi isolates in vitro about nine days after dual culture was 53.9%, 62.5%, 38.9%, 38,3%, 26.9%, 29,4%, and 34.7%, respectively. Endophyte study with Trichoderma morphospecies 2 showed that the isolate could colonize 84% of the root, 60% of the stem, and 80% of leaf tissues three weeks after inoculation through roots. Therefore, the research results demonstrate the presence of endophytic fungi derived from the chili plant that is potential to control wilt disease in vivo.

Effect of Some Microorganisms on Controlling Fusarium Wilt of Roselle (Hibiscus sabdariffa L.)

Roselle (Hibiscus sabdariffa L.) is one of the most crucial medicinal plants all over the world. The present study was carried out with the intention of solving some problems related to soil-borne diseases. Fusarium oxysporum is associated with wilt disease of roselle plant. The application of some microbiota i.e., a mixture of Pseudomonas fluorescens (PSR-11), Bacillus subtilis (BSR-8), Pleurotus ostreatus and mycorrhizeen® individually or in combination were investigated for controlling wilt disease, growth, and yield of roselle plant. The study was conducted in sandy textured soil under sprinkler irrigation of Ismailia Agricultural Research Station, Ismailia, Egypt. Under greenhouse conditions, all the tested bioagents reduced wilt incidence and increased the percentage of survived plants. The conglomeration of the bacterial mixture of Pseudomonas fluorescens and Bacillus subtilis, Pleurotus ostreatus and mycorrhizeen® was more effective in controlling wilt disease than using any of them individually. The application of the investigated bioagents showed a significant increase in phenol, photosynthetic pigments, and dehydrogenase contents, as well as root colonization percent. The obtained results showed the ability of B. subtilis and P. fluorescens to produce lytic enzymes such as β-1-3 glucanase, β-1-4 glucanase, chitinase and protease, in addition to their production of siderophore and HCN. The consortium of all microbiota gave the best results for growth and yield parameters of roselle plant.

Partial purification and characterization of 2, 4-diacetylphloroglucinol producing Pseudomonas fluorescens VSMKU3054 against bacterial wilt disease of tomato.

We find out the antimicrobial potential of partially purified 2,4-diacetylphloroglucinol (DAPG) against Ralstonia solanacearum and fungal plant pathogens isolated from tomato rhizobacterium Pseudomonas fluorescens VSMKU3054. The present study is mainly focused on the control of wilt disease of tomato by our isolate VSMKU3054 and DAPG. The cell free culture filtrate of P. fluorescens VSMKU3054 was significantly arrested the growth of R. solanacearum and fungal pathogens such as Rhizoctonia solani, Sclerotium rolfsii, Macrophomina phaseolina and Fusarium oxysporum compared to control. The existence of DAPG from the crude metabolites of P. fluorescens VSMKU3054 was confirmed on TLC with Rf value 0.34, which is coincide with that of authentic phloroglucinol. The partially purified DAPG exhibited much higher activity against R. solanacearum at 30 µg/ml than the fungal plant pathogens compared to control. The antimicrobial partially purified compound was identified as DAPG by UV, FT-IR and GC–MS analysis. The percentage of live cells of R. solanacearum when supplemented with DAPG at 30 µg/ml, significantly controlled the living nature of R. solanacearum up to 68% compared to tetracycline and universal control observed under high content screening analysis. The selected isolate P. fluorescens VSMKU3054 and DAPG significantly controlled wilt disease of tomato up to 59.5% and 42.12% on 3rd and 7th days compared to positive and negative control by detached leaf assay. Further, in silico analysis revealed that high interaction of DAPG encoding protease with lectin which is associated with R. solanacearum. Based on our findings, we confirmed that P. fluorescens VSMKU3054 and DAPG could be used a potential bio inoculants for the management of bacterial wilt disease of tomato.

Biological control of bacterial wilt of solanaceous vegetable crops - a review

Bacterial wilt of solanaceous crops is caused by Ralstonia solanacearum (Smith) Yabuuchi et al. which includes a “species complex” that provides it high heterogeneity. The wilt disease reduces the production of crops significantly. The bacterium R. solanacearum is gram-negative, small rod with rounded ends, non-fluorescent, non-endospore forming, strict aerobe and has polar flagella (when present). All phylotypes i.e. I, IIA, IIB, III & IV, race 1 & 3 and biovars 1, 2 2T, 3 & 4 infect solanaceous crops to cause wilt disease. The pathogen has variability during its survival in the soil for a longer period which restricts the control of wilt disease. Besides, there are no such chemicals available to control wilt disease effectively at field level. An alternative approach is biological control which is ecofriendly and very effective in integrating with other management practices for controlling the disease. Biological control includes microbes, organic matter, botanicals, animal wastes and resistant varieties which are used either alone or combined with other methods to improve disease management. The microbes particularly fungi and bacteria have advantage over chemical control such as self-sustaining, self-spreading, reduced input by renewal capacity, long-term disease suppression and eco-friendly.

Phenolic compounds involved in pine wilt disease: HPLC-based method development and validation for their quantification

Pine Wilt Disease, caused by the pine wood nematode, is a severe and unsolved sanitary problem of pine forests in Europe and Eastern Asia. However, not all Pinus species are affected. Differences in their phenolic pattern may imply different resistance/susceptibility to the nematode, but this topic has not yet been investigated in detail. Therefore, a thorough analysis of phenolic compounds in different Pinus species is crucial to assess their role as markers of resistance/susceptibility to the nematode in order to understand the defense mechanisms against it, and to develop innovative strategies to manage and control wilt disease. A HPLC-based method for the simultaneous quantification of gallic acid, ferulic acid, epicatechin, taxifolin, rutin, resveratrol and secoisolariciresinol in Pinus tissues was developed and validated. The method exhibits good sensitivity, low limits of detection and quantification, good precision, and high specificity and selectivity. The method was successfully applied to the quantification of the above-mentioned phenolic compounds in thirty-six extracts of Pinus halepensis and Pinus sylvestris tissues, before and after nematode inoculation. The results showed that the studied compounds can act as potential interspecific markers of resistance/susceptibility to the pathogen. Hence, the method lends itself readily for application in scientific studies and routine analysis on this sanitary issue.

Microbiological Assessments in a Cut Flower Crop Polytunnel Field Trial Adopting Soil Covering and Microbiocides for Fusarium Wilt Suppression

Cut flower Matthiola incana were raised by local commercial cultivators in a polytunnel. The field soil beds were either left uncovered as normal or covered with polythene sheets (except a hole for plant plug space). Average temperatures in the top 5 cm soil under cover dropped from 28 oC to 18 oC compared to its spiking up to 37 oC in uncovered counterparts. Microbiological analyses indicated that soil covering induced two log10 folds reduction of the wilt causal fungi Fusarium oxysporum and concomitantly increased one log10 fold wilt antagonistic natural soil inhabiting fungi populations. Standard dip/drench mixtures of commercial and local isolates microbiocides (bacteria) applied to M. incana plug roots improved plant health assessed by visible scores of the level of damage or wilt symptoms under soil covered treatments. Scanning electron microscopy, cultural and 16S rRNA PCR analyses revealed potent antifungal bacteria attached to the hyphal surfaces of F. oxysporum as ectosymbionts that may have implications for virulence regulation and host plants’ wilt disease control. Our microbiological data support the prospects of combining physiological and microbiological interventions upon covering the soil surface that offers the local horticulturists an evidence based sustainable means of Fusarium wilt control suppression in polytunnel crops.

Characterization of Bacillus spp. from the rhizosphere of potato Granola varieties as an antibacterial against Ralstonia solanacearum

Abstract. Prihatiningsih N, Arwiyanto T, Hadisutrisno B, Widada J. 2020. Characterization of Bacillus spp. from the rhizosphere of potato Granola varieties as an antibacterial against Ralstonia solanacearum. Biodiversitas 21: 4199-4204. Ralstonia solanacearum is one of the important wilt pathogens that significantly decreased potato yields in Indonesia. One of the strategies to control wilt disease is the use of Bacillus sp. that isolated from potato rhizosphere. Bacillus sp. is an antagonist against some phytopathogenic fungi and bacteria. The objectives of the study were to identify 5 strains of Bacillus spp. (B46, B209, B211, B298, and B315) that is capable of suppressing the growth of R. solanacearum. Experimental assays were performed to determine the growth inhibition of R. solanacearum by culturing in a two-layer medium. The identification of Bacillus spp. was performed based on physiological and biochemical characters and molecular identification. Results showed that all of Bacillus spp. are capable of suppressing the growth of R. solanacearum. B. subtilis B315 isolate was the most effective biocontrol agent in inhibiting R. solanacearum growth by a bacteriostatic mechanism. All Bacillus spp. have similarities in physiological and biochemical characters. Based on the molecular analysis, Bacillus sp. B46, B209, B211, and B298 were homologous to B. subtilis subspecies spizizeni RRLKE2, whereas Bacillus sp. B315 was homologous to B. subtilis strain WIFD5.

Endophytes from Gnetum gnemon L. can protect seedlings against the infection of phytopathogenic bacterium Ralstonia solanacearum as well as promote plant growth in tomato

Endophytes are beneficial plant microbes which help the plants by producing various plant growth promoting substances and also by acting as biocontrol agents against various plant pathogens. In the present study, evaluation of endophytic bacteria isolated from Gnetum gnemon, an ethnomedicinal plant was carried out for their plant growth promoting (PGP) activity and antagonistic potential against bacterial wilt pathogen Ralstonia solanacearum. Initially a total of 40 endophytic bacteria were isolated which were clustered into 13 groups based on RFLP and BOX-PCR fingerprinting. These 13 representative isolates belonged to different genera of Bacillus (9), Solibacillus (1), Staphylococcus (2) and Caballeronia (1). Among them, six isolates were positive for production of IAA, the value of which ranged from 11.16 to 27.63 μg mL−1. Phosphate solubilisation in the range of 106.4 to –212.7 μg mL−1 was shown by three isolates. Eight isolates producedammonia, the value of which ranged from 1.3 to 6.1 μmol mL−1. All tested isolates were positive for siderophore production. For extracellular enzyme production, 7 isolates were positive for protease, 8 for cellulase and 10 for amylase production. The isolates were also tested for their antagonistic activity against R. solanacearum in vitro and in planta assay using tomato seedlings. Staphylococcus warneri GL1 showed the highest biocontrol efficacy of 77.67 % followed by Bacillus velezensis GL3 i.e. 70.1 %. R. solanacearum antagonistic isolates were analysed for the presence of antimicrobial peptide biosynthesis genes bmyB, srfAA, fenD and ituC. All the antagonistic isolates showed the presence of all four genes, except the isolate Bacillus velezensis GMC2, where the gene for fengycin synthetase (fenD) was absent. Based on in vitro PGP traits, three isolates Bacillus velezensis GL3, Bacillus atrophaeus GMC1 and Bacillus megaterium GS2 were selected, these three endophytic bacteria individually and their consortia were tested for in planta PGP activities in tomato plants. Application of Bacillus velezensis GL3 alone and consortia of three isolates showed significant improvement in growth parameters such as shoot length, fresh weight and dry weight in a pot experiment. Colonization of endosphere of treated tomato seedlings by the endophytic isolate Bacillus velezensis GL3 was confirmed by visualization of colony morphology and BOX-PCR fingerprinting. Our study highlights the potential of endophytes associated with unexplored plants like G. gnemon for development of bioformulation aimed at enhancing plant growth and bacterial wilt disease control.

Seed biopriming with antagonistic microbes and ascorbic acid induce resistance in tomato against Fusarium wilt

Seed biopriming is an emerging technique to enhance seed germination under stress conditions. An integrated approach of tomato seed biopriming with ascorbic acid, Trichoderma asperellum BHU P-1 and Ochrobactrum sp. BHU PB-1 was applied to observe the response against wilt pathogen of tomato Fusarium oxysporum f. sp. lycopersici (FOL). Tomato seeds bioprimed with the aforementioned application expressed augmented seed germination and activated of defense response. Seed germination was recorded higher (80 %) at low concentration (1 pM) of ascorbic acid as compared to high concentration of 1 mM (41 %). Combination of both ascorbic acid and antagonistic microbe treatments (T5 & T6) significantly reduced disease incidence (up to 28 %) in tomato plants at 10 days. T5 and T6 treated plants exhibited higher accumulation of total phenol content and increased activity of Phenylammonia lyase (PAL), Peroxidase (PO), Chitinase (Chi) and Polyphenol oxidase (PPO) as compared to control (T1) plants. ROS formation in the form of H2O2 was also found to be reduced in combined treatment. Histochemical analysis revealed that phenylpropanoid pathway (lignin deposition) was more activated in combined priming treatment plants as compared to individual treatment upon challenge inoculation with FOL. Transcript expression analysis of defense genes confirmed the up-regulation of PAL (2.1 fold), Chi (0.92 fold), Pathogenesis related proteins (PR) (1.58 fold) and Lipoxygenase (Lox) (0.72 fold) in T6 treatment as compared to T1 treatment plants at 96 h. This study reveals that ascorbic acid treatment with antagonistic microbes through seed priming effectively induced seed germination and elicited defense mechanism to control wilt disease in tomato plants.

On Farm Demonstration of Management of <i>Fusarium</i> Wilt Disease of Chickpea Under Rainfed Conditions in Mid Hill Region of Jammu, Jammu & Kashimir, U.T., India

Chickpea is one of the most vulnerable crop to attack of pests and diseases causing huge production losses. Among the diseases, chickpea wilt poses a severe problem in rainfed areas of Jammu region. It was observed that chickpea seeds treated with Trichoderma viride (soil application) recorded 21.50% wilt incidence followed by Trichoderma viride (seed application) 35.25%, neem seed cake 47.00%, Carbendazim 48.90%, Thiram 50.14% and Captan 56.50%. While Trichoderma viride (soil application) gave 78.50% (highest) wilt disease control, followed by Trichoderma viride (seed application) 64.75%, neem seed cake 53.00%, Carbendazim 51.10%, Thiram 49.86%, Captan 43.50% and least in check. Recommendations of the results were repeated in the 4 farmers field in Reasi district, disease incidence were 25.40% but after applying of Trichoderma viride (soil application) diseases incidence reduced to 7.95% only and it was reduced to 6.75% (Table 2). While yield of chick pea was enhanced from 5.25 to 9.20 q/ha and maximum 9.80 q/ha against least farmers’ practices i.e. 5.25% only.

Native Trichoderma harzianum strains from Argentina produce indole-3 acetic acid and phosphorus solubilization, promote growth and control wilt disease on tomato (Solanum lycopersicum L.)

Trichoderma fungi are considered as suitable biofertilizers, since they could increase the efficiency of the use of nutrients in plants and are used as biocontrol agents against plant pathogen. The aim of this study was to characterize a set of Trichoderma strains isolated from horticultural and near-pristine soils from the Argentine Pampas, and to evaluate their potentiality as a growth promoter and as a biocontroller of Fusarium wilt disease on tomato. Nineteen collected strains, identified as T. brevicompactum, T. gamsii and T. harzianum, were tested for their ability to produce the auxin indole 3-acetic acid (IAA), solubilize phosphate and biocontrol F. oxysporum. Twelve strains reduced growth of pathogenic fungus over 50% and four of them (named FCCT 16, FCCT 58, FCCT 199-2 and FCCT 363-2) exhibited IAA highest production (ranging 13.38–21.14 µg/ml) and were able to solubilize phosphate (ranging 215.80–288.18 µg/ml of calcium phosphate). Tomato plants inoculated with those four strains increased chlorophyll content, shoot length, fresh and dry weight of shoot and roots, and reduced F. oxysporum wilt disease between 10 and 30%. On the basis of our results, we conclude that soils of the Argentine Pampas harbor Trichoderma strains with beneficial dual effects which could be of interest for the development of commercial products.

Fusarium wilt of pea- A mini review

Pea (Pisum sativum L.) belongs to family Leguminosae and includes both ornamental and edible forms i.e. the garden pea and field pea. It is one of the most important legume crops and is grown over a greater part of the world. This crop is affected by a number of bacterial, fungal and viral diseases which under favourable conditions can significantly decrease both yield and quality. Fusarium wilt is an economically significant disease causing losses to the tune of 30–40 per cent. Symptoms of the disease include true wilt and near wilt. The first symptoms are usually a yellowing of lower leaves and stunting of plant growth ultimately leading to wilting of plants. This disease is caused by Fusarium oxysporum f.sp. pisi for which different races 1,2,3,4,5,6,7,8,9,10 and 11 were described on the basis of virulence. The pathogen is soil borne and can survive in the soil in the absence of pea crop for 10 years or longer as thick walled chlamydospores. A soil temperature of 23–27°C is most favourable for true wilt development. There is no satisfactory control of wilt disease once the fungus is introduced and gets established in the soil, however, different strategies viz. cultural practices, disease resistant varieties, biological and chemical methods can be integrated to achieve the best management of the disease.