Pepper Root Rot Research Articles

Some Chemical and Biological Methods to Control Pepper Root Rot Disease in Iraq

Background: Pepper growing fields in the Babil and Wasit governorates in Iraq, are suffering from a decline in production due to the spread of root rot diseases. The use of biological control techniques, such as the use of beneficial bacteria in the rhizosphere and natural plant extracts, along with chemical fungicides, has recently contributed to reducing the damage of plant pathogens globally. Methods: In this research, the main cause of root rot disease in pepper plants was isolated and diagnosed using polymerase chain reaction technology using (TEF-1α) gene, antagonistic activities of 75 rhizobacterial isolates, natural extracts of garlic and nerium and the fungicides of Promess and Tecto 500 SC were tested in vitro against the pathogen, then the superior bacterial isolates were identified. The ability of biological and chemical agents to control the disease was tested under greenhouse conditions according to the completely randomized design (CRD). Result: The results of isolation showed that the fungus Fusarium solani was dominance and the isolate Fsw45 was the most virulent. 3 of 75 rhizobacterial isolates outperformed the pathogen in an antagonistic tests and identified as Pseudomonas mendocina, P. fluorescens and Staphylococcus kloosii also the fungicides and botanical extracts showed significant antagonistic activities as well in vitro. Under greenhouse conditions, the fungicide treatments excelled in disease control by 100%. As for the 3 bacterial isolates, they achieved a significant reduction in the percentage of disease incidence and disease severity index, their abilities were higher than the nerium and garlic extracts.

First report of Pythium aphanidermatum and Pythium myriotylum causing root rot on chili pepper (Capsicum annuum L.) in Guizhou, China

Chili peppers (Capsicum annuum L.) are popular globally as a vegetable and condiment and are particularly popular in Guizhou, China. Root rot, the most prevalent soil-borne disease affecting chili peppers, is widespread in Guizhou. In 2023, it was observed in 10–20% of six fields, leading to significant economic losses. Eight strains were isolated from rotten roots of ‘Huaxi’ chili samples to support the need for appropriate pathogen control. Four strains were identified as Pythium aphanidermatum (strains: HSLJ-2, HSLJ-4) and Pythium myriotylum (strains: LDLJY-1, LDLJJ-3) through morphological analysis of sporangia, oospores, antheridia, and oogonia; multi-locus phylogenetic analysis of the internal transcribed spacer and mitochondrial cytochrome c oxidase subunit 1 gene regions; followed by pathogenicity testing using inoculated autoclaved wheat seeds. The two Pythium species were thus identified as novel causal agents of chili pepper root rot in Guizhou, China.

Detection and Analysis of Chili Pepper Root Rot by Hyperspectral Imaging Technology

The objective is to develop a portable device capable of promptly identifying root rot in the field. This study employs hyperspectral imaging technology to detect root rot by analyzing spectral variations in chili pepper leaves during times of health, incubation, and disease under the stress of root rot. Two types of chili pepper seeds (Manshanhong and Shanjiao No. 4) were cultured until they had grown two to three pairs of true leaves. Subsequently, robust young plants were infected with Fusarium root rot fungi by the root-irrigation technique. The effective wavelength for discriminating between distinct stages was determined using the successive projections algorithm (SPA) after capturing hyperspectral images. The optimal index related to root rot between each normalized difference spectral index (NDSI) was obtained using the Pearson correlation coefficient. The early detection of root rot illness can be modeled using spectral information at effective wavelengths and in NDSI, together with the application of partial least squares discriminant analysis (PLS-DA), least squares support vector machine (LSSVM), and back-propagation (BP) neural network technology. The SPA-BP model demonstrates outstanding predictive capabilities compared with other models, with a classification accuracy of 92.3% for the prediction set. However, employing SPA to acquire an excessive number of efficient wave-lengths is not advantageous for immediate detection in practical field scenarios. In contrast, the NDSI (R445, R433)-BP model uses only two wavelengths of spectral information, but the prediction accuracy can reach 89.7%, which is more suitable for rapid detection of root rot. This thesis can provide theoretical support for the early detection of chili root rot and technical support for the design of a portable root rot detector.

Assessment the Efficiency of the Bioagent Bacillus velesensis and the Biohealth Formula with Fungicide Beltanol in Control of Fusarium solani Causing Pepper Root Rot

The aim of this study was isolating and diagnosing the causative agent of root rot of pepper in Karbala province and control it using some biological applications. The results showed that the main pathogenic fungus of root rot and damping-off pepper in Karbala Province was Fusarium solani. This fungus was highly pathogenic by inhibition germination of all pepper seeds on the culture medium and in plastic pots. The treatment of integration between among Bacillus velesensis + Biohealth + Beltanol displayed the highest effectiveness in control of the pathogenic F.solani, as it reduced the disease incidence and severity to 9.00, 6.66%, respectively, compared to the pathogenic fungus alone, which amounted to 100%, 86.6%, respectively.

In vitro screening of native rhizobacteria and selection of Bacillus atrophaeus for the biocontrol of pepper root rot in the Gansu Province, China

In vitro screening of native rhizobacteria and selection of Bacillus atrophaeus for the biocontrol of pepper root rot in the Gansu Province, China

The Complete Genome Sequence Resource of Rhizospheric Soil-Derived Bacillus velezensis Yao, with Biocontrol Potential Against Fusarium solani-Induced Pepper Root Rot.

The pepper rhizospheric soil-derived Bacillus velezensis Yao from the Shangqiu region of the Henan province in China possesses antagonistic activity against Fusarium solani, which causes pepper root rot. In this report, we introduced the entire genomic sequence of B.velezensis Yao, which is 3,951,864 bp long, with 46.61% G+C content, and 4,097 genes. Using antiSMASH analysis, we predicted 12 gene clusters that encode for secondary antimicrobial metabolites and multiple genes that regulate plant bacterial interactions. The B.velezensis Yao genome data may be a valuable resource as this strain may serve as an effective biocontrol agent against pepper root rot.

Evaluation of the Biocontrol Efficiency of Bacillus subtilis Wettable Powder on Pepper Root Rot Caused by Fusarium solani.

The plant-growth-promoting rhizobacteria (PGPR) B. subtilis PTS-394 has been utilized as a biocontrol agent (in a wettable powder form) due to its excellent ability to suppress tomato soil-borne diseases caused by Fusarium oxysporum and Ralstonia solanacearum. In this study, we evaluated the biocontrol efficiency of Bacillus subtilis PTS-394 wettable powder on pepper root rot in pot experiments and field trials. B. subtilis PTS-394 and its lipopeptide crude extract possessed excellent inhibition activity against Fusarium solani, causing pepper root rot; in an antifungal activity test B. subtilis PTS-394 wettable powder exhibited a good ability to promote pepper seed germination and plant height. The experiments in pots and the field indicated that B. subtilis PTS-394 wettable powder had an excellent control effect at 100-fold dilution, and its biocontrol efficacy reached 69.63% and 74.43%, respectively. In this study, the biocontrol properties of B. subtilis PTS-394 wettable powder on pepper root rot were evaluated and its application method was established. It was concluded that B. subtilis PTS-394 wettable powder is a potential biocontrol agent with an excellent efficiency against pepper root rot.

Suppression of Pepper Root Rot and Wilt Diseases Caused by Rhizoctonia solani and Fusarium oxysporum.

Pepper is vulnerable to soil-borne fungal pathogens such as Rhizoctonia solani and Fusarium oxysporum. The potential of beneficial rhizosphere microorganisms to control R. solani and F. oxysporum f.sp. capsici was evaluated in pepper plants. Paenibacillus polymyxa and Trichoderma longibrachiatum were isolated from rhizospheric soil samples of healthy pepper plants. In vitro, both isolates caused clear reductions in the radial growth of root rot and wilt pathogens. Scanning electron microscopy displayed lysis and abnormal shape of the pathogens in dual cultures with P. polymyxa and T. longibrachiatum. The incidence and severity of root rot and wilt diseases were significantly reduced in pepper plants treated with the growth-promoting fungi (PGPF isolates; Fusarium equiseti GF19-1, Fusarium equiseti GF18-3, and Phoma sp. GS8-3), P. polymyxa, or T. longibrachiatum in comparison to the control. Moreover, the induction treatments led to increased pepper growth compared with their control. The defense related gene (CaPR4) expression was shown to be significantly higher in the treated plants than in the control plants. In conclusion, the antagonistic isolates (P. polymyxa and T. longibrachiatum) and PGPF isolates have a clear impact on the prevention of root rot and wilt diseases in pepper plants incited by R. solani and F. oxysporum f.sp. capsici. The expression of the CaPR4 gene added to the evidence that PGPF isolates generate systemic resistance to pathogen infections.

Diagnosis and bioefficacy of endospheric trichoderma strains of selected medicinal plant on pepper root rot and vascular wilt in Cameroon

We attempted to detect and assess the pathogenic potentials of the mycoflora causing wilt and root rot in pepper and to screen the antagonistic potentials of two medicinal plant-derived Trichoderma species (Trichoderma atroviride T32 and Trichoderma sp. N97) against the more pathogenic fungal pathogens. The taxonomic characterization revealed that the Fusarium spp. (56.9%), constituted of F. oxysporium f. sp. capsici (47.1%) and F. solani (9.7%) was the most distributed. Axenic soil infestation with the recovered pathogens successfully induced root rot, leaves chlorosis and root rot, resulting in 52% and 68.92% root stunting in sweet and hot pepper, respectively. The bioagents produced up to 64% inhibition of pathogens’ mycelia growth in confrontation assay, presumably by antibiosis. The ethyl acetate-based extracts from the Trichoderma spp. (10 mg/ml) completely lysed the Fusarium conidia and chlamidospores. The tested bioagents are no doubt promising biological control candidates against pepper wilt and root rot pathogens.

Pepper root rot resistance and pepper yield are enhanced through biological agent G15 soil amelioration.

Pepper root rot is a serious soil-borne disease that hinders pepper production, and efforts are being made to identify biological agents that can prevent and control pepper root rot. Our group recently discovered and produced a biological agent, named G15, which reduces the diversity and richness of fungi and bacteria when applied to pepper fields. In the soil of the G15-treatment condition, the pathogenic fungus Fusarium was inhibited, while the richness of beneficial bacteria Rhodanobacter was increased. Also, the ammonia nitrogen level was decreased in the G15-treatment soil, and the pH, total carbon, and total potassium levels were increased. Compared to the control condition, pepper yield was increased in the treatment group (by 16,680 kg acre−1). We found that G15 could alter the microbial community structure of the pepper rhizosphere. These changes alter the physical and chemical properties of the soil and, ultimately, improve resistance to pepper root rot and increase pepper yield.

The Competitive Potential of Different Trichoderma spp. to Control Rhizoctonia Root Rot Disease of Pepper (Capsicum annuum L.)

Five isolates of Trichoderma spp. were investigated, in a preliminary study, for their efficiency in controlling Rhizoctonia root rot of pepper (Capsicum annuum L.). GC-MS analysis of most active Trichoderma spp. extracted secondary metabolites were studied. The major compounds identified by GC-MS analysis included hexadecanol, nonadecene, 1,2-benzenedicarboxylic acid, octadecenoic acid (z) and hexadecanol, 2-methyl. These compounds have been found to play an important role in controlling plant diseases. The results of antagonistic activity of three isolates proved higher efficiency in controlling R. solani. Browning of the R. solani mycelium was observed where mycoparasitism occurred. The parasitism of R. solani hyphal cells by Trichoderma harzianum was studied by light and scanning electron microscopy. Sequence data of R. solani isolates (R.1, R.2 and R.4) have been submitted to the GenBank under accession numbers (MZ267232, MZ267234 and MZ267689), respectively. The most effective isolates i.e., T. asperellum, T. hamatum and T. harzianum in addition to their mixture were formulated in different forms i.e., suspension and powder, then tested at different concentrations under the greenhouse and protected cultivation conditions. Results of greenhouse studies indicated that all isolates and their mixture were effective in controlling pepper root rot disease and increasing percentage of survived plants. Moreover, results showed that suspension was effective than powder in reducing the disease. Higher bio-control efficiency at protected cultivation was obtained when the mixture of isolates was used at high concentration. Most of the Trichoderma spp. studied in the present work have been able to reduce severity of R. solani.

First report of Rhizoctonia solani AG 4 HG-III causing root rot of pepper in Kyrgyzstan

First report of Rhizoctonia solani AG 4 HG-III causing root rot of pepper in Kyrgyzstan

Effect of Trichoderma on Growth and Sporangia Production of Phytophthora capsici

Phytophthora capsici is the main agent of chili pepper root rot, causing significant yield losses in commercial fields worldwide. Management of this plant pathogen has been difficult due to its ability to develop fungicide resistance, therefore biocontrol of P. capsici appears to be a promising alternative. In this study we evaluated the effects of three species of Trichoderma: T. harzianum (Th-7), T. koningiopsis (Tk NRRL50190) and T. asperellum (Ta NRRL50191) on two mexican isolates of P. capsici (RDP-1 and RDP-2) obtained from commercial pepper fields in Aguascalientes, Mexico. The ability to inhibit mycelia growth of P. capsici was tested with in vitro assays, followed by the quantification of sporangia after dual confrontations. All Trichoderma isolates inhibited the mycelia growth of the phytopathogen, but only Ta and Tk showed mycoparasitism. Sporangia production of P. capsici RDP-1 and RDP-2 was significantly reduced by Trichoderma isolates, compared to the non-confronted control, except for the Th-RDP-2 confrontation. Sporangia of RDP-1 significantly decreased by 95.6%, 81.3% and 78% after confrontations with Tk, Ta and Th, respectively; and by 76% and 85.4% in RDP-2 by Tk and Ta, respectively. The results suggest that Ta, Tk and Th could be used as potential biocontrol agents of Phytopthora root rot, however, further studies are necessary to test the in vivo protection of Ta, Tk and Th and their synergistic effects against Phytophthora root rot of chile peppers and other P. capsici susceptible solanaceous and cucurbitaceous crops such as tomatoes, squash, melons, and cucumbers.

Rhizoctonia Root Rot of Pepper (Capsicum annuum): Comparative Pathogenicity of Causal Agent and Biocontrol Attempt using Fungal and Bacterial Agents

Rhizoctoniaroot rot of pepper (Capsicum annuum L.) is becoming serious in Tunisia. Comparative pathogenicity tests performed for Rhizoctonia solani isolates recovered from pepper and potato showed that Rhiz.7 and Rhiz.4 were the most aggressive. They reduced by 53.5%-91.4% the aerial part fresh weight of inoculated cv. Baklouti plants relative to control. Rhiz.7 decreased by 81%-88% the root fresh weight on cvs. Beldi and Baklouti. Various fungal and bacterial agents were tested against R. solani. Dual culture trials showed that Trichoderma harzianum, T. viride and Glicladiumvirensgrew and sporulated profusely over R. solani colonies and altered its hyphae. Pseudomonas huttiensis 69, P. aureofaciens 31 and Burkholderiaglathei 35 reduced pathogen growth by 9.71-12.87%. These bio-agents were tested for their effects on rhizoctonia root rot disease and pepper growth. On cv. Beldi, pre-emergence damping-off, noted after 15 days, was suppressed by 55 (for G. virens), 45 (for T. viride) and 50% (for T. harzianum). This inhibition reached 57.14% using Bacillus pumilus 420 and P. putida 227. Tested on pepper cv. Altar, all tested fungi decreased by 40% post-emergence damping-off, and significantly increased the plant height of R. solani -inoculated and treated plants by 21.13 (for T. viride) to 36.34% (for T. harzianum) relative to control. P. aureofaciens 314 and P. putida 227 completely suppressed R. solani post-emergence expression. Treatments with P. aureofaciens 314, P. aureofaciens 31, Bacillus pumilus 420, P. fluorescens Pf and P. putida 227 induced a significant increase in their height compared to control. An improvement of the aerial part fresh weight by 54.54, 48.09 and 47.74%, as compared to control, was induced by P. aureofaciens 314, B. glathei 35 and P. huttiensis 69, respectively.

Evaluation of Pepper Root Rot Resistance in an Integrated Phytophthora Blight Management Program

Phytophthora crown and root rot, incited by Phytophthora capsici, is an important and limiting disease in bell pepper (Capsicum annuum) production in many vegetable-producing areas of the United States. Soilborne oospores initiate disease when conditions are favorable, and polycyclic production of sporangia and zoospores occurs on infected plant tissue during the production season. Raised-bed plant culture, resistant cultivars, and oomycete-specific fungicides are commonly used to manage P. capsici. The objective of this study was to evaluate four bell pepper cultivars and four experimental breeding entries (collectively termed entries) for resistance to P. capsici in Michigan (MI) and New Jersey (NJ) and to determine the effect of a fungicide program on plant health and yield. The pepper cultivars included Camelot X3R (susceptible), Aristotle (intermediately resistant), and Paladin and Archimedes (resistant) for comparison. Disease symptoms included plant wilting and sunken necrotic stem lesions. In NJ, blighting of stems and foliage was also observed. In MI, >90% of the susceptible ‘Camelot X3R’ plants in the untreated plot wilted and died in both years of the study. All other entries had <10% plant wilting and death in 2014. In 2015, ‘Archimedes’ and ‘Paladin’ had <10% wilt and plant death; ‘Aristotle’, AP4835, 13SE12671, and AP4841 had 10% to 30% symptomatic plants. The fungicide program reduced disease to <10% for all entries except ‘Camelot X3R’ in 2014 and ‘Aristotle’ and ‘Camelot X3R’ in 2015. In NJ, ‘Paladin’, ‘Aristotle’, and ‘Camelot X3R’ (2014) and ‘Archimedes’, ‘Aristotle’, and ‘Camelot X3R’ (2015) had >30% plant wilting and death in the untreated plot. In the fungicide-treated plot, AP4841, AP4835, and AP4839 (2014), and AP4839 (2015) had <10% of plants with disease symptoms; ‘Camelot X3R’ and ‘Aristotle’ had >40% plant wilting and death in both years. In MI, marketable yield for ‘Paladin’ in fungicide-treated and untreated plots was significantly higher than the other entries in both years (P < 0.05). AP4839 was the highest yielding entry in NJ in the untreated plot, and AP4839 and ‘Archimedes’ were highest yielding in the fungicide-treated plot in 2014 and 2015, respectively. Fruit size for 13SE12671 was the largest among entries in both locations. There was no entry × fungicide program interaction in MI.

Integrated Control of Pepper Root Rot

Isolation trials of pathogens causing root rot disease of pepper plants collected from El Behera and El-DakahliaGovernorates revealed the presence of two isolates of Rhizoctonia solani, one of each of Fusarium solani, F. oxysporum,Alternaria alternate, Sclerotium bataticola and Phytophthora capsaci. Isolation from seeds of 2 pepper cvs. Sweet(California wonder) and hot (Cayenne) exhibited the presence of A. alternate, F. solani and S. bataticola. F. solani wasmore present on sweet pepper (41.5%) than hot pepper (38.2%).The reaction of the pepper cultivars to the isolated fungi showed that the mixed infection; with all tested fungi, wassevere pathogenic, the sweet cultivar was more susceptible (Total mortality 73%) than the hot cultivar (47%), both peppercvs, showed significant decrease in shoot and root fresh and dry weight compared with the control.In vitro studies; 2 isolates of each T. harzianum, T. viride and one of Bacillus subtilis were used. The results showedthat B. subtilis significantly decreased the growth diameter of the tested pathogens. T. viride isolate 2 and T. harzianumisolate 1 were more effective. Tazolien fungicide at 0.19 g/ li was superior followed by Rhizolix-T at 0.45g/l. Hot pepperoil and camphor oil completely inhibited the growth of F. solani, S. bataticola and R.solani at 500 mg/l.Green house experiments showed that T. harzianum significantly decreased infection percentages (less than 7%) inboth cultivars with mixed inoculation infection. Rhizolix-T. at 0.45 g./l. was next, where it decreased the infection up to 3-10% (53-83% untreated control). The use of hot pepper oil and camphor oil significantly decreased infection up to 20% inhot pepper and 30-37% in sweet pepper.Seed treatment increased significantly the chlorophyll content of leaves. Estimation of total phenols in leaves ofpepper cultivar showed increase of phenol content after infection, the increase was more in hot pepper than the sweetcultivar.

Efficacy of chloropicrin application by drip irrigation in controlling the soil-borne diseases of greenhouse pepper on commercial farms in Poland

Three demonstration experiments were conducted on commercial greenhouse farms to assess the efficacy of chloropicrin (CP), applied by drip irrigation, in controlling Verticillium wilt and root rot disease complex of bell pepper, in comparison with dazomet at 40 g m−2. Chloropicrin was applied through drip irrigation system at 20, 30 and 40 g m−2 of emulsified commercial formulation. The concentration of CP in water was constant, and the required doses were obtained by delivering different amounts of the irrigation water per area unit (from 12.5 to 33 mm). The highest mean efficacy in reducing the inoculum density of Verticillium dahliae in the soil at all locations was obtained after CP application at 30 and 40 g m−2, about 85 and 86%, respectively. The number of viable microsclerotia recovered from the soil on the day of pepper planting was significantly correlated with the final incidence of Verticillium wilt disease (r = 0.962). The highest mean efficacy in controlling Verticillium wilt of pepper (86.4%) was obtained after soil treatment with CP at 40 g m−2, and ranged from 80.2 to 95.6%. The yield was stronger correlated with root rot severity (r = −0.849**) than with progression of Verticillium wilt, expressed by AUDPC (r = −0.651**). The dominant soil-borne pathogen responsible for pepper root rot was Colletotrichum coccodes. All chemical treatments provided a significant reduction in root rot severity compared to the untreated control. On-thefarm evaluation revealed that soil fumigation with drip-applied chloropicrin presents a feasible option for pepper growers.

Mapping of a Novel Race Specific Resistance Gene to Phytophthora Root Rot of Pepper (Capsicum annuum) Using Bulked Segregant Analysis Combined with Specific Length Amplified Fragment Sequencing Strategy.

Phytophthora root rot caused by Phytophthora capsici (P. capsici) is a serious limitation to pepper production in Southern China, with high temperature and humidity. Mapping PRR resistance genes can provide linked DNA markers for breeding PRR resistant varieties by molecular marker-assisted selection (MAS). Two BC1 populations and an F2 population derived from a cross between P. capsici-resistant accession, Criollo de Morelos 334 (CM334) and P. capsici-susceptible accession, New Mexico Capsicum Accession 10399 (NMCA10399) were used to investigate the genetic characteristics of PRR resistance. PRR resistance to isolate Byl4 (race 3) was controlled by a single dominant gene, PhR10, that was mapped to an interval of 16.39Mb at the end of the long arm of chromosome 10. Integration of bulked segregant analysis (BSA) and Specific Length Amplified Fragment sequencing (SLAF-seq) provided an efficient genetic mapping strategy. Ten polymorphic Simple Sequence Repeat (SSR) markers were found within this region and used to screen the genotypes of 636 BC1 plants, delimiting PhR10 to a 2.57 Mb interval between markers P52-11-21 (1.5 cM away) and P52-11-41 (1.1 cM). A total of 163 genes were annotated within this region and 31 were predicted to be associated with disease resistance. PhR10 is a novel race specific gene for PRR, and this paper describes linked SSR markers suitable for marker-assisted selection of PRR resistant varieties, also laying a foundation for cloning the resistance gene.

Damping-Off and Root Rot of Pepper Caused by Fusarium oxysporum in Almería Province, Spain.

Bell pepper (Capsicum annuum L.) is intensively cropped in ~9,920 ha of plastic houses in southern Spain. In summer 2013, pepper seedlings cv. Melchor, Acorde, Galena, Prometeo, and Souleria, with 4 to 8 leaves, grown in a nursery greenhouse near El Ejido, Almería Province, exhibited root rot and stunting. Incidence of symptomatic plants was ~35% among over 10 million. Fusarium sp. was consistently isolated on potato dextrose agar (PDA) from primary and secondary roots of symptomatic plants. Eight single spore isolates (FC1, FC2, FC3, FC4, FC5, FC6, FC11, and FC12) were identified on PDA, carnation leaf-piece agar medium, and Spezieller Nährstoffarmer agar medium as Fusarium oxysporum because of their production of macroconidia (20.5 to 38.2 × 3.9 to 5.8 μm) containing mostly three or rarely four septa, with foot-shaped basal cells. Microconidia (5.9 to 16.5 × 2.6 to 4.7 μm) with 0 to 1 septa formed on false heads on short monophialides and chlamydospores. DNA was extracted from various isolates used in the pathogenicity test, and a portion of the elongation translation factor 1-alpha using primers EF-1 and EF-2 was amplified and sequenced. All the pathogenic isolates were identical, and they differed from the non-pathogenic in 6 to 8 base pairs. The isolates had 99% homology with several isolates of F. oxysporum corresponding to different specialized forms (vasinfectum, lilii, lycopersici, and radicis-lycopersici) at the Fusarium-ID database (1) and GenBank. The sequences of two isolates, FC-6 and FC-12, were deposited in GenBank with accession nos. KF928930 and KF928931, respectively. The pathogenicity of these eight isolates was tested on pepper cv. Melchor in 1-liter containers filled with vermiculite in August and October. Seedlings were inoculated at sowing. PDA plates fully covered with the colony of each isolate were separately blended and homogenized with 300 ml of sterile distilled water. Inocula (5.0 × 105 to 9.4 × 106 conidia/ml) were poured at 50 ml per container. Each experiment had four replicates and 5 to 6 plants per replicate. Treatments with different isolates were arranged in a randomized complete block design. In both experiments, the same number of uninoculated seedlings served as controls. The plants were maintained for 40 days following inoculation in a greenhouse with mean temperatures of 24.0 to 32.4°C and 23.6 to 31.20°C for August and October experiments, respectively. In both experiments, all control plants and those inoculated with FC2, FC3, and FC4 remained asymptomatic. The first wilting occurred 11 days after inoculation. At the end of the August experiment, plants inoculated respectively with FC1, FC5, FC6, FC11, and FC12 showed symptoms in 60, 70, 65, 80, and 90% and 25, 0, 15, 40, and 25% died. At the October experiment, plants showed symptoms in 91.7, 95.8, 100.0, 91.7, and 87.5% and 83.3, 75, 62.5, 83.3, and 79.2% died. Symptomatic plants exhibited damping-off, necrosis of the primary and secondary roots, and sometimes necrotic streaks on the stem. F. oxysporum was consistently recovered from the primary root of symptomatic plants in both experiments and 10 of these isolates were inoculated in a third pathogenicity test, being all pathogens, thus fulfilling Koch's postulates. Although F. oxysporum was reported in peppers (2), to our knowledge, this is the first report of F. oxysporum as the causal agent of damping-off and root rot in pepper seedlings in Almería Province.

Role of Endomycorrhizae on Controlling Stem- and Root-Rot of Pepper Caused by Sclerotium rolfsii

This study was designed to investigate the effect of inoculation time with vesicular arbuscular mycorrhizal (VAM) fungi, Glomus spp., on the interaction between root-rot and stem-rot of pepper caused by Sclerotium rolfsii Sacc. as well as its growth. The results indicated that addition of Glomus spp. significantly increased the shoot and root fresh and dry weight with significant decrease to the disease severity (59-89%). Effect of the mycorrhizal inoculation using five species of Glomus by two different inoculation treatments on incidence of Sclerotium stem-rot as well as crop parameters of pepper plants inoculated with the tested fungus was investigated. Generally, mycorrhizal inoculation increased pepper shoot and root fresh and dry weight compared with uninoculated plants. Meanwhile, seedlings arose from seeds treated with Glomus spp. increased growth parameters and yield. G. coronatum and G. luteum were the best mycorrhizae to increase crop parameters. On the other hand, G. etunicatum, G. diaphanum and G. luteum were the best to protect pepper plants against S. rolfsii.