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Showing 37 results for Biocontrol


Volume 0, Issue 0 (1-2024)
Abstract

Ganoderma boninense Pat. is a persistent soil-borne pathogen that causes significant losses in oil palm (Elaeis guineensis Pat.) productivity. In this study, we evaluated the antifungal activity of volatile organic compounds (VOCs) produced by a fungal isolate, later identified as Paraconiothyrium archidendri F10, against G. boninense. The isolate was identified based on ITS-rDNA sequence analysis and BLASTn results. VOCs produced by P. archidendri F10 were found to inhibit G. boninense mycelium growth by up to 55.8% in four days, with the mycelium exhibiting wavy, non-smooth, and wrinkled morphology, abnormal branching, fused, defective hyphae, and lysis from within. The major VOC components were esters, with 7,9-ditert-butyl-1-oxaspiro[4.5]deca-6,9-diene-2,8-dione being the most abundant (16.72%). The other top-ranking components were 2-O-(6-ethyloctan-3-yl) 1-O-hexyl oxalate (8.71%), methyl heptadecanoate (8.66%), and butyl acetate (5.66%), with minor components comprising less than 5% of the total VOCs. Our findings suggest that P. archidendri F10 has potential as a biofungicide for controlling G. boninense in the field.

Volume 1, Issue 1 (3-2012)
Abstract

Soybean, Glycine max (L.) Merr is one of the most important oilseed plants in the world and Phythophthora root and crown rot is a significant limiting factor for its planting. In the present study the antagonistic effect of 12 Trichoderma spp. in vitro and these Trichoderma spp. in combination with Bradyrhizobium japonicum in vivo on Phytophthora sojae and soybean growth were tested. In laboratory tests the effects of Trichoderma isolates were studied in dual culture, volatile compounds and culture filtrate metabolites. The most hyphal growth inhibitions were obtained using T. virens, T. orientals and T. brevicompactum in dual culture tests and T. atroviride in volatile compounds test. The effects of Trichoderma culture filtrates on P. sojae hyphal growth were studied at six concentrations in CMA medium and the results showed that culture filtrates of all species inhibited the hyphal growth and that different concentrations had different inhibitory effects. The most inhibition was obtained by T. virens and T. brevicampactom culture filtrates. The greenhouse tests were carried out as two experiments. In the first experiment the effects of coated seeds with Trichoderma isolates and B. japonicum, alone and in combinations, on control of P. sojae and in the second experiment the effect of these two biocontrol agents on soybean growth, alone and in combinations, were assayed. In the first experiment, germination percentage, damping-off, seedling vigour index (SVI) and disease severity were measured and results showed that T. brevicompactum as alone and in combinations, was the most effective species. In the second experiment, coated seeds with Trichoderma isolates and B. japonicum, as alone and in combinations, significantly promoted the growth of treated seeds and the most effective species were T. orientals, T. brevicompactum and T. spirale. Hence, results indicate that T. brevicompactum, as the second most common species after T. harzianum in Iran, was the most successful species applied individually and in combinations with B. japonicum to act as biocontrol agent for P. sojae and was also able to promote plant growth.



Volume 1, Issue 4 (12-2012)
Abstract

Biological efficacy of Trichoderma species may differ due to variations in ecosystems. This study was conducted to assess the biocontrol efficacy of some native Trichoderma isolates against Fusarium oxysporum, an important causal agent of potato wilt disease under laboratory and greenhouse conditions in Shahrood Agricultural Research Center, Shahrood, Iran during 2006-2007. Fourteen isolates were collected among which eight showed promising ability in inhibiting growth of the pathogen through dual culture and production of volatile and non-volatile metabolites but T. asperellum (T2) and T. atroviride (T3) were almost more efficient than other isolates in inhibiting the mycelial growth of the pathogen in comparison to control (P ≤ 0.01). Eight isolates were evaluated against the disease under green house condition. Potted plants treated with Trichoderma isolates + F. oxysporum showed lower disease incidence in comparison to Fusarium infested control (P ≤ 0.05). Best disease control was observed in potted plants treated with F. oxysporum + T. asperellum (T2) showing 2.5% disease incidence in contrast to Fusarium infested control, in which disease incidence was 73%.

Volume 2, Issue 3 (9-2013)
Abstract

Various molecular techniques are available to make differences and to study the genetic divergences among species and populations, of which the most efficient ones are PCR-based markers. One of these methods, molecular fingerprinting, enables the distinction of closely related populations. ISSR-primers are universal primers that can be used for such studies. The utility of these primers was tested for threepopulations of Eretmocerus mundus Mercet (Hym, Aphelinidae), a primary parasitoid of the whiteflies. Of the 60 ISSR primers, that were checked, as many as 64 bands were obtained from 16 primers. The band sizes ranged from above 200 to 1000 bp for different primers. The rate of divergence among the bands was strong enough to make a clear difference among the studied specimens; however the intricacy of using these primers is very much for studying the divergence among several populations. Therefore, sequencing of specific regions of DNA could bring more success to find out divergence among populations of these tiny parasitoids.    

Volume 2, Issue 4 (12-2013)
Abstract

The cypress family, Cupressaceae, has a global dispersion. Currently, endophytic microorganisms from plants are being investigated for their diversity and bioactivities. Here, we aimed at exploration and characterization of cultivable endophytic fungi from foliar tissues of Cupressaceae, i.e. Cupressus arizonica, C. sempervirens var. cereiformis, C. sempervirens var. fastigiata, Juniperus excelsa, Juniperus sp. and Thuja orientalis. Asymptomatic fresh foliar tissues, collected from mature healthy plants, were sterilized and the inner layers were plated on culture media at 26-28 °C for 2-12 weeks, until fungal colonies emerged and were purified. Endophytic Penicillia i.e. Penicillium aurantiogriseum, P. chrysogenum, P. commune, P. echinulatum, P. expansum and P. viridicatum were the dominant fungi recovered. Results indicated that both host plant and geographical location of sampling affected the biodiversity and bioactivity of endophytic Penicillia. Results also indicated that those endophytic Penicillia had significant bioactivities. According to our results, both intra-and extra-cellular secondary metabolites from all isolated Penicillia had significant cytotoxic and antifungal effects against the model fungus Pyricularia oryzae and cypress fungal phytopathogens Diplodia seriata, Phaeobotryon cupressi and Spencermartinsia viticola. Further studies indicated the significant antimicrobial bioactivities of superior Penicillia against model bacteria. Altogether, this study highlights, for the first time, the biodiversity of endophytic Penicillia from Cupressaceae plants and documents their significance for agrochemical/drug discovery and for plant disease biocontrol.  

Volume 2, Issue 4 (12-2013)
Abstract

Application of Trichoderma species is a harmless method in controlling soil borne plant diseases thus reducing hazardous pesticide use and environmental pollution. Some Trichoderma isolates performing proper inhibitory effect against Fusarium oxysporum f. sp. tuberosi under laboratory and green house conditions were screened against wilt disease of potato caused by this pathogen under field condition in Shahrood Agricultural Research Center, Iran, during 2009-2010. Results of two years field studies indicated that T. virens (T7) followed by T. asperellum (T2) were superior to others in reducing the disease in comparison to infested control. In comparison to Fusarium infested plots, yield was higher in all plots treated with Trichoderma, but highest yields were obtained from plots in which T. virens (T7) and T. asperellum (T2) were involved respectively. It might be stated that isolates of T. virens and T. asperellum are among the effective biocontrol agents against Fusarium wilt disease of potato and can be used as formulated biofungicides in reducing this disease.

Volume 3, Issue 2 (6-2014)
Abstract

The aphid species, Cinara pini (Linnaeus, 1758) reported in our previous work as a new aphid on pinus trees for Iran, was described using the classic method and through analysis of COI gene sequence. In the next step, we addressed the efficiency of the entomopathogenic fungus, Lecanicillium longisporum (Zimm.) Zare and Gams strain LRC 190, on the aphid. The fungus was administered to the second instar nymphs and adults using topical application procedure. The results indicated that the entomopathogen caused 90% mortality in adults over seven days at a concentration of 108 spores/ml, while the same control level was achieved for nymphs by 8 × 107 spores/ml. The LC50 values were obtained as 1.2 × 106 and 6.9 × 105 spores/ml for adults and nymphs, respectively. The present study suggests that the entomopathogenic fungus, L. longisporum could be considered as a potential candidate in biocontrol programs of C. pini. This is the first report on the pathogenicity of L. longisporum on C. pini.

Volume 3, Issue 3 (9-2014)
Abstract

Striga hermonthica is a parasitic weed which largely constrains maize and sorghum production in Western Kenya. The weed mostly invades small scale farms and depending on severity, it may cause damage ranging from 10% to complete crop failure thereby aggravating the food insecurity in that region. This study aimed at evaluating fungal isolates as possible biocontrol agents against the weed. Fungi were isolated from diseased Striga hermonthica and their virulence efficacy against the weed tested in a greenhouse. All the fungal isolates tested caused infection and consequently death of the weed. Fusarium incarnatum had the highest infection rate of 92% followed by Gibberella intricans and F. chlamydosporum at 90% each. Fusarium oxysporium caused the highest mortality of 60% with Gibberella intricans, causing the least mortality of 36%. F. oxysporium was the most aggressive and potent fungal isolate against the weed hence a suitable candidate for exploitation as a mycoherbicide against the weed.  

Volume 3, Issue 4 (12-2014)
Abstract

Macrophomina phaseolina is one of the major yield limiting factors of melons in tropical and subtropical regions. For eco-friendly and effective management of the disease, 24 gamma induced mutants from Trichoderma harzianum were evaluated against three isolates of the pathogen representing three geographically different regions viz. Khorasan (isolate 1), Garmsar (isolate 2) and Khuzestan (isolate 3). The isolates of Trichoderma (mutants and wild type) were evaluated against the pathogen in dual culture and through production of volatile and non-volatile inhibitors. Maximum growth inhibition was observed in Th1, Th4, Th15, Th9 and Th22 mutants after three days. In greenhouse evaluation against M. phaseolina (isolate 1) among the inoculated treatments minimum plant infection was observed in Th9 treatment (28% disease reduction) as compared to infected control and among the uninoculated treatments Th1and Th9 mutants resulted in maximum growth of roots and shoots of melon plants as compared to uninfected control. These mutants are introduced as potential candidates against M. Phaseolina. The results proved that gamma-mutagenesis by enhancing the antagonistic properties of T. harzianum 65 can be useful for the biocontrol of soil borne plant pathogens such as Macrophomina phaseolina.

Volume 4, Issue 1 (3-2015)
Abstract

On the basis of preliminary in vitro screening tests, a competent strain of Pantoea agglomerans ENA1 (P. agg. ENA1) recovered from soybean nodule was evaluated for its antagonistic activity against Macrophomina phaseolina causal agent of charcoal rot of soybean. The results of various in vitro assays showed that P. agg. ENA1 is capable of exerting strong antagonistic effect against M. phaseolina inhibiting its mycelial growth up to 89% as compared to control. The results showed a significant reduction of the disease as measured in host-plant weight increase, reduced microsclerotial coverage of the host tissues and decreased population of the pathogen in soil. Soils treated with the antagonist in presence of the pathogen resulted in 40% increase in aerial fresh weight and 63% decrease in root and stem surface covered by microsclerotia as compared with control. Furthermore, a significant decrease in the pathogen population ranging from 73 to 76% was observed in sterile and non-sterile soils, respectively. P. agg. ENA1 is suggested as a potent biocontrol agentthat provides excellent rhizosphere colonization and control of M. phaseolina    

Volume 4, Issue 3 (9-2015)
Abstract

Application of antagonistic agents in the rhizosphere of plants is an important approach in control of soil-borne pathogens. Establishment and persistence of biocontrol agents in the soil is a major concern in biological control. This study aimed to determine the effect of plant debris of oak forests on activity of Pseudomonas fluorescens and Trichoderma vierns against Meloidogyne javanica in tomato in green house conditions. In different treatments, both or one of the bioagents were applied to the soil inoculated with M. javanica and amended or unamended with oak plant debris. Based on the results, the growth–related factors of tomato improved in those treatments, in which plant debris were mixed with the soil. In case of nematode-related factors, the number of galls on roots decreased significantly in pots amended with plant debris. Maximum reduction in reproduction factor was observed in treatments with one or both of the biocontrol agents. In comparison to unamended treatments, the rate of reduction in root gall was 56.3% for treatments receiving T. virens and maximum increase in dry weight of root was observed in soils treated with P. fluorescens or T. virens, 68.2% and 56.1%, respectively.

Volume 5, Issue 3 (9-2016)
Abstract

Fusarium proliferatum, as a toxigenic fungus, is one of the important agents of onion basal rot (FBR). Among the control methods of the disease, biological control is considered as one of the best options. In this study, Trichoderma harzianum strain T100 at the rate of 1 × 106 cfu/g was mixed with pot soil artificially infested with F. proliferatum. Also Glomus mosseae was applied to each pot at the rate of three grams of soil containing 80 chlamydospores/ml. Combination of T100 and G. mosseae was used as well. Onion seeds were disinfected & planted in pots, arranged in completely randomized design in 4 replicates under greenhouse condition and finally, the individual or combined effects of these bioagents were assessed on FBR control and also root colonization by Glomus 23, 30 and 36 days after sowing. Inoculation of Arbuscular mycorrhizae improved onion growth effectively, but its biocontrol effect was not considerable. Trichoderma amended soil decreased disease incidence by 25% but its usefulness as biocontrol agent was reduced in the course of time. AM root colonization was decreased in plants in presence of Trichoderma. Nevertheless, the disease control in combination of Trichoderma and Glomus treatment was better than the treatments by each one of the agents singly. The disease control achieved by fungicide seed treatment was inferior to that of Trichoderma and Glomus in combination.  

Volume 6, Issue 1 (3-2017)
Abstract

Surfactin is one of the most efficient biosurfactants excreted by Bacillus subtilis which displays the highest potential as induced systemic resistance elicitor among all metabolites produced by B. subtilis. Environmental factors have considerable effect on surfactin production. In this study surfactin production of two Bacillus subtilis strains were analyzed using high performance liquid chromatography (HPLC). C14 and C15 surfactins were detected in the ethanol extract from acid-precipitated supernatant. HPLC analyses of different media including Nutrient Broth (NB) medium, NB plus 40g/l glucose, NB plus 10% soil extract and NB plus 10% plant extract medium, clearly showed that these bacteria produced different amounts of surfactins C14 and C15 in these media. Surfactin production in NB/plant medium was relatively the highest in quantity. Microelements analysis of media containing plant and soil extract with atomic absorption spectrometry showed high amounts of Fe, Mn and Zn in medium containing plant extract compared with that of soil extract. Since these elements play an important role in surfactin production, high amounts of Fe, Mn and Zn in NB/plant extract medium compared to the NB/soil extract medium could be the possible reason for relatively higher amounts of surfactins C14 and C15 produced in NB/plant medium. So adding these important elements to soil may boost biocontrol effect of B. subtilis against plant pathogens.

Volume 7, Issue 1 (3-2018)
Abstract

In recent years, biological control has become a promising and ecologically friendly alternative to chemical control in the management of soil-borne plant diseases and several biological control agents have been introduced as potential bio-fungicides. The aim of this study was to investigate different biological control agent consortia against Rhizoctonia solani root rot disease of common bean. Bacillus pumilus INR7, Trichoderma harzianum and Rhizophagus intraradices were used individually or in combination. There were two application methods: simultaneous application of biocontrol agents with the plant pathogen, and pre-inoculation of biocontrol agents one month before the pathogen. Treatments containing B.pumilus INR7 were the best treatments for suppression of the disease in the simultaneous application method, where B. pumilus INR7 + T. harzianumreduced the disease up to 54%. However, in pre-inoculation method T. harzianum alone was the only treatment that reduced disease severity up to 49% compared to the infected control; other treatments did not haveany significant effect on disease severity. In current study, combination of T. harzianum and R. intraradices was unable to decrease disease severity and improve plant growth. This phenomenon was common in both simultaneous and pre-inoculation experiments. However, results showed that B. pumilus INR7 and R. intraradices were compatible with each other. Their combination not only decreased the disease, but also improved the dry weight of common bean in both application methods. Our results revealed that B. pumilus INR7 had positive interaction with T. harzianum. This combination increased their ability to suppress root rot disease and improve plant health, significantly. Overall, combinations of biocontrol agents have good potential to be applied in modern agriculture, but such combinations need to be checkedin advance for their compatibility in greenhouse and field experiments.

Volume 8, Issue 1 (1-2019)
Abstract

Aphis gossypii Glover (Hemiptera: Aphididae) is an important cucumber pest especially in greenhouse. The efficacy of simultaneous release of generalist predator, Orius albidipennis Reuter (Hemiptera: Anthocoridae) and a specialist parasitic wasp, Aphidius colemani Viereck (Hymenoptera: Braconidae), was evaluated in laboratory conditions against the pest. For this purpose, investigations were carried out on preference of the predator between parasitized and non-parasitized aphids. In addition, production of volatile infochemicals between the natural enemies (NEs) was studied by olfactometry trials. In another part of this research, systemic production of volatile synomone by the infested cucumber plants for attraction of each NE was examined by the olfactometry tests. Results revealed that O. albidipennis had no obvious preference to either the parasitized or non-parasitized aphids, while both NEs were significantly attracted to volatiles emitted from infested host plants. Our findings revealed that each of the NEs avoided odors which indicated the presence of another intraguild competitor. The documented facts from the entire study reveal that the NEs are good biocontrol agents against A. gossypii on cucumber, but their avoidance from each other makes simultaneous release of the predator and parasitic wasps unsuitable for biological control of this aphid.
 
 
 

Volume 8, Issue 3 (7-2006)
Abstract

Trichoderma harzianum (T39), T.virens (DAR74290), T.viride (MO), T. harzianum (M) and TrichderminB a commercial formulation of T. harzianum(Bi) were evaluated as potential biological agents for the control of charcoal stem rot in melon caused by Macrophomina phaseolina. Cell-free metabolites of T. harzianum(M), T. harzianum (T39) and T. virens (DAR 74290) inhibited growth of M. phaseolina completely in vitro and appeared to be fungicidal. T. viride (MO) inhibited fungal growth from 34.9% to 71%. T. harzianum (T39), T. harzianum (M), T. virens (DAR 74290), T. viride(MO) and T. harzianum (Bi) were tested for their ability to protect melon plants from disease caused by M. phaseolina in a glasshouse experiment. The percentage of stand plants with the antagonist alone or in combination with the pathogen was significantly (p<0.05) greater than in plants inoculated with the pathogen alone. The percentages for the stand plants in treatments were as follows: T. harzianum (T39), T. harzianum (M), T. virens (DAR 74290), M. phaseolina, M. phaseolina + T. virens (DAR 74290), M. phaseolina + T. harzianum (T39) and M. phaseolina + T. harzianum (M),at 95, 100, 97.5, 15, 64.25, 75.25 and 47.55 percent respectively. The percentage for the stand plant in the commercial Trichodermin B + M. phaseolina treatment (96.7%) was greater than for M. phaseolina alone (46.7%) and demonstrated the best result in the control of charcoal stem rot in melon.

Volume 8, Issue 4 (8-2019)
Abstract

Biocontrol of Fusarium oxysporum f. sp. ciceris by six Bacillus species was evaluated. Also plant growth promoting potential of the bacteria was assessed. Results showed that four bacterial strains produced the chitinase and cellulase enzymes and all isolates produced indole acetic acid. Bacillus licheniformis proved to be the most productive of hydrogen cyanide and particularly, Bacillus firmus solubilized phosphorus on Pikovskaya solid and liquid media. The majority of strains were able to produce siderophore and three produced NH3. Results showed that the Flip05-156C chickpea variety was less susceptible to Foc isolates compared to Flip93-93C and there was a clear difference in pathogenicity of the Foc isolates. Thus, Foc1 and Foc2 isolates caused 31.25% and 41.66%, plant mortality, respectively. As regards PGPR effect, results showed that B. licheniformis gave the best branching number, stem length and root weight of both chickpea varieties. However, Bacillus lentus distinctly improved the root length while Bacillus amyloliquefaciens improved weight of the vegetative parts.
Younes Karimpour, Majid Jafarlu, Hossein Lotfalizadeh,
Volume 9, Issue 2 (6-2023)
Abstract

This is the first case of host record for parasitoid wasps of the genus Diglyphus Walker (Hymenoptera, Eulophidae) from the Anthomyiidae (Diptera) family. This result is based on specimens of D. anadolucus Doğanlar, 1982 which reared from parasitized larval specimen of Pegomya terebrans (Rondani) as a leaf miner of cotton thistle, Onopordum acanthium L. (Asteraceae). Diglyphus anadolucus is reported from Iran for the first time. Some biological notes and morphological characteristics of D. anadolucus along with related photographs are given. An updated checklist of the twelve known Diglyphus species in Iran togther with their host associations is also provided.
Sangeeta Rawat, Sandeep Kumar,
Volume 9, Issue 2 (6-2023)
Abstract

Psyllaephagus malloticolae Rawat & Kumar sp. nov. a parasitoid of Trioza malloticola (Crawford) (Hemiptera, Psylloidea, Triozidae) causing galls on leaves of the Kamala tree, Mallotus philippensis Muell, 1865 is described from India. An updated key to all the known allied species of Psyllaephagus Ashmead from India is also provided. The new species comes close to P. garuga Sudhir & Singh, 2011 but differs from it in having Funicular V the longest segment, mid-tibial spur longer than basitarsus, and the exserted ovipositor sheath.

Arefeh Gholami, Reza Hosseini,
Volume 10, Issue 1 (3-2024)
Abstract

Damsel bugs (Hemiptera, Nabidae) are predatory insects belonging to the order of Hemiptera. During the spring-summer of 2021–2022, nabid specimens were collected from Guilan province and adjacent areas. In this study, three species (four subspecies) belonging to two genera were collected and identified: Himacerus mirmicoides (O.Costa, 1834); Nabis viridulus Spinola, 1837; Nabis pseudoferus pseudoferus Remane, 1949 and Nabis pseudoferus orientarius Remane, 1962, furthermore, four species (four subspecies) belonging to two genera were examined from the insect collection of the Natural History Museum of the University of Guilan (UGNHM) including Himacerus major (A.Costa, 1842); Nabis pseudoferus transcaspicus Remane, 1962; Nabis punctatus punctatus A.Costa, 1847 and Nabis capsiformis Germar, 1838. In this paper, based on the morphological characteristics and genitalia of males, brief diagnostic descriptions, illustrated identification key and digital images of species habitus were provided to facilitate the identification of Nabidae of Guilan province and its adjacent areas.

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