Fungal Plant Pathology Research Papers (original) (raw)

A technique was standardized to screen for resistance to stem rot (Sclerotium rolfsii Sacc.) in groundnut (Arachis hypogaea L.). A total of seven different inoculation techniques were screened by using susceptible genotype TMV-2. The techniques involved inoculation of 10 day old groundnut plants raised in pots by spreading mycelial propagules of S. rolfsii grown on sorghum grain medium (SGM) on soil surface, Inoculum spread on the soil surface and covered with groundnut leaf debris, Inoculum placed around the collar region, Inoculum placed around the collar region and covered with groundnut leaf debris, Inoculum mixed in the soil, Inoculum mixed in the soil and covered with groundnut leaf debris, Agar disc method. Among these techniques inoculum spread on the soil surface and covered with groundnut leaf debris was found to be most efficient in getting highest per cent incidence of stem rot (84.86%) and pod rot (70.48%). How to view point the article : Poornima and Sunkad, Gururaj (2020). Standardization of inoculation technique to identify the sources of resistance against stem and pod rot of groundnut. Internat. J. Plant Protec., 13(1) : 58-61,

- by Poornima Timoti
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- Plant-pathogen interactions, Fungal Plant Pathology

A survey (2012-2014) of forest plant pathogenic fungi in Vikarabad, Narsapur, Manchippa, Bhadrachalam, Eturnagaram, Mannanoor, Adilabad and other areas revealed 20 pathogenic fungi. Among these eleven form new additions to the fungi of... more

- by Dr.D. Nagaraju
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- Mycology, Mycology and Plant pathology, Medicinal Plants, Fungal Biodiversity

Beauveria bassiana (Balsamo) Vuillemin, a white muscardine fungus has drawn attention worldwide as potential biocontrol agent against insect-pests since decades. In the rice ecosystem, B. bassiana has been established as potential mycoinsecticide against major insect-pests of rice viz., Cnaphalocrocis medunalis, Nilaparvata lugens, Dicladispa armigera, Scirpophaga incertulas etc., but its efficacy against phytopathogens of rice in simultaneous application is least studied. Among major phytopathogens of rice, bacterial leaf blight incurs a yield loss of up to 12-75%, affecting crop at seedling, tillering and vegetative stages. Therefore, recent studies have inclined towards unravelling antimicrobial potential of B. bassiana as effective plant disease antagonist, thereby, opening a newer dimension in dualpurpose crop protection strategies. In the present study, antagonistic abilities of fifteen (15) native isolates of B. bassiana were evaluated against Xanthomonas oryzae pv. oryzae causing bacterial leaf blight of rice by conducting agar-plug diffusion and inverted plate assays. The results showed that, majority of B. bassiana isolates viz., Bb31, Bb45, Bb48, Bb25, Bb53 were able to inhibit bacterial growth, with maximum per cent inhibition was recorded in the range of 60-84% through development of inhibition zone. Further, antibacterial ability of B. bassiana was also attributed to release of non-volatile inhibitory metabolites responsible for the formation of inhibition zone on the bacterial lawn. These findings provide substantial evidences on antibacterial abilities of B. bassiana against X. oryzae pv. oryzae and further provides a scope to test the efficacy of B. bassiana against bacterial leaf blight of rice in the glasshouse and field condition in addition to their potential entomogenous behaviour against insect-pests of rice.

- by Lipa Deb
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- Fungal Plant Pathology, Beauveria bassiana, Bacterial blight of rice, Plant Pathology

The influence of different application rates of the plant growth-promoting rhizobacterium, Pseudomonas aeruginosa, population densities of the root-knot nematode, Meloidogyne javanica, moisture and other plant-associated bacteria in the suppression of root rot–root knot disease complex of tomato are described. The impact of these factors on bacterial rhizosphere and inner root and shoot establishment are also presented. The highest inoculum level of P. aeruginosa (7.4 × 108 cfu ml−1) in the presence of the lowest population density of M. javanica (500 J2/plant) caused the greatest reduction in gall formation due to M. javanica. The number of root–knot nematodes recovered from soil and roots treated with P. aeruginosa were also significantly reduced. Root infection caused by the soilborne root-infecting fungi Fusarium oxysporum, F. solani and Rhizoctonia solani was also effectively suppressed following application of P. aeruginosa. A P. aeruginosa-Bacillus subtilis treatment was the most effective in the suppression of root-rot disease complex with enhancement of plant growth. Biocontrol and growth promoting potential of the bacterium was enhanced when soil was kept at 50% or 75% moisture holding capacity, whereas a 25% MHC reduced bacterial efficacy. Rhizosphere population of P. aeruginosa declined drastically in P. aeruginosa-Bradyrhizobium japonicum treatments. Rhizosphere colonisation by P. aeruginosa seems to be governed by two factors: Initial inoculum size of the bacterium and severity of the root-knot disease. Endoroot and endoshoot colonisation of the bacterium was dependent on degree of root-colonisation by Fusarium oxysporum. An inoculum level 2.5 × 108 cfu/ml of P. aeruginosa was optimal for the enhancement of plant growth, whereas inoculum below this level reduced plant growth.

- by Syed Ehteshamul-Haque
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- Fungal Plant Pathology

Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flower plant and is commercially grown in about 719 ha in Andhra Pradesh with an annual production of 503 t. Out of this, majority of the area is in Chittoor and the casual organism was identified as Sclerotium rolfsii Sacc. and the disease was named as collar rot (Harinath Naidu, 2000). The symptoms observed were shrunken and brown coloured bark which first appear on the collar region later spreading to roots. When the bark was peeled off, the internal tissue revealed brown to black discolouration with rotten roots. Yellow to pink discolouration followed by shedding of leaves was observed leading to drying of plants.

- by Aruna sri Pinagari
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- Fungal Plant Pathology

166 10.3. Diagnosis Methods and Field Monitoring of Strawberry Diseases 167 10.3.1. Molecular methods applied to phytopathogenic fungi 167 10.3.2. Past and present diagnosis methods 168 10.3.3. PCR alternatives applied to fungal diagnosis 169 10.3.4. Other molecular techniques used to study fungal pathogens 172 10.3.5. Web-based decision support systems 174 10.3.6. Proteomics advances in strawberry fungal pathogens 181 10.4. Conclusions 184

- by Amjad M Husaini
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- Horticulture, Fungal Plant Pathology, Strawberry, Plant Disease

micro and macro-algae different culturing techniques

- by Mai Mohsen
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- Phycology, Algae Culture, Algae Biotechnology, Fungal Plant Pathology

One of the major issues facing humankind is global food security. A changing climate, coupled with a heightened consumer awareness of how food is produced and legislative changes governing the usage of agrichemicals for improving plant health and yield, means that alternative, more integrated and sustainable approaches are needed for crop management practices. To this end, there is increasing recognition of the value of the role of microbial inoculants in agriculture. The focus of this review is to understand how plant-growth-promoting bacteria and arbuscular mycorrhizal fungi can play a part in improving crop yield by promoting the health status of the plant through the sequestration of various nutrients and in the control of plant diseases.

Research was done on rice grains showing fungal symptoms.

- by GHAZALA BUTT
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- Biology, Fungal Plant Pathology

Cumin (Cuminum cyminum L.) is one of the oldest seed spice and the important production
constraint is wilt caused by Fusarium oxysporum f. sp. cumini Prasad and Patel (Foc) and crop
losses could be up to 60%. Maximum population of Foc was estimated at 0-5 cm soil depth in the
presence of crop, but the population density tended to decline progressively with distance from
the surface. Resting structures of the Foc, the chlamydospores, survive in the soil for more than
10 years. The inoculum density in the soil increases with each year of cumin cultivation and is
directly proportional to disease incidence in the field. In this review, an effort has been made to
compile research findings generated during past four decades on symptomatology, ecology and
management strategies like summer ploughing, crop rotation, sowing time, soil solarization,
efficient bio control agents, organic amendments, seed dressing fungicides and tolerant varieties.
In the absence of resistant sources against Foc, to reduce population of pathogen below the
economic threshold level, integration of cultural, chemical and biological control measures is the
only effective way to manage wilt in the fields.

- by ritu mawar
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- Fungal Plant Pathology

The objective of this study was to examine Fusarium verticillioides and possible methods to cheaply, easily and efficiently measure its contamination in maize. The principle method proposed was to detect change in CO2 respiration using non-invasive infrared (IR) sensors. The validity and usability of the new IR sensor, Photosynq, was confirmed while the experiments were carried out. In an idealized scenario, the concentration of CO2 in the air should increase with increased fungal concentrations, based on the principle that F. verticillioides respires CO2. However, this study found that the respiration of maize grain is more complicated than previously believed, because of the diverse interactions between different fungal strains, bacteria and environmental conditions. Even when carried out in a controlled laboratory setting, there is too much uncertainty to be able to quantify fungal contamination with a high degree of accuracy.

- by Dana Brems, DPM
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- Fungal Plant Pathology, Plant Pathology

Onion crop grown in west coast of sothern India has been seriously affected by the problem of onion twister disease charetorized by the symptoms viz., twisting of leaf and neck, slight to prominent galls in roots with root proliferation and scanty discolouration of root system. Survey carried out during rabi/summer of 2011-12 and 2012-13 revealed the prevalence of such disease in all the major onion cultivating areas of Karnataka (India). The highest disease index of 29.37 and 24.05 per cent was noticed Uttar Kannada district during 2011-12 and 2012-13 respectively. Aetiological investigations revealed the association of a nematode with symptomatic onion plants having root galls. Isolated nematode when inoculated, resulted in slender plants with typical abnormal elongation of leaf with proliferation and neck twisting during initial stage and at later stage whole plant appeared to be abnormal showing typical twisting symptoms. Artificially inoculated plant with typical symptoms were found to have severe galling with typical hooks like roots. At later stage discoloration and complete destruction of root system demonstrated the Koch's postulate for the involvement of isolated nematode in the disease. Identity of the nematode was confirmed as Meloidogyne graminicola by morphometric and perineal pattern studies. This is the first report of association of rice root knot nematode involved in onion twister disease.

- by Suresh Patil
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- Ecology, Mycology and Plant pathology, Fungal Plant Pathology, Plant Pathology

Global food security is vulnerable due to massive growth of the human population, changes in global climate, the emergence of novel/more virulent pathogens, and demands from increasingly discerning consumers for chemical-free, sustainably produced food products. Bacterium- based biological control agents (BCAs), if used as part of an integrated management system, may satisfy the above demands. We focus on the advantages, limitations, problems, and challenges involved in such strategies.

- by Siva Velivelli
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- Agricultural Engineering, Botany, Plant Ecology, Agribusiness

Rice is affected by quite a number of diseases that results in high yield losses. Among the fungal diseases, kernel smut is known to occur worldwide in many countries. Biological method of plant disease management seems to be an alternative to chemical fungicides in managing rice diseases. In this study, effects of some bioagents on Tilletia barclayana, the causal agent of rice kernel smut were investigated, under greenhouse conditions. The study focused on mechanis m mediating suppression of T. barclayana by investigating the effect of different bioagents on the activities of defense related enzymes, i.e peroxidase (POX), polyphenoloxidase (PPO), phenylalanine ammonia lyase (PAL). Among 15 fungal and bacterial isolates, Bacillus pumilus was found to be the most promising bioagent (BCA) for controlling the disease. Generally, the tested bioagents significantly increased the activities of defense related enzymes and total protein content compared with control treatment. Obtained data suggests use of efficient and environmentally safe bioagents to control rice kernel smut disease.

- by Mohsen M Elsharkawy
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- Biochemistry, Biological Control, Enzymes, Fungal Plant Pathology

P. infestans strains have been isolated in pure culture from blighted samples, collected in the
Moscow, Leningrad, Astrakhan, Smolensk, and Kostroma regions, Mariy El Republic, and Belarus.
The fungicide resistance of collected strains has been tested in Petri dishes with agar medium.
The most efficient fungicides are azoxystrobin and dimethomorph. The efficiency of fluazinam,
chlorothalonil, and mancozeb is also rather high. Therefore, the application of these fungicides
in recommended dosages can provide a successful potato late blight control. The strains, highly
resistant to metalaxyl, has been revealed in the Moscow and Smolensk regions, and also in Belarus.

The current research was planned to evaluate the response of 37 wheat (Triticum aestivum) genotypes against leaf rust resistance under field conditions during 2017-18. Areas under disease progress curve (AUDPC) of all the varieties were calculated. Leaf rust severity response was variable among the tested genotypes. Out of thirty-seven genotypes, five wheat lines i.e. 17BT007, 17BT013, 16BT008, 16BT010 and 16BT011 were immune. Seven lines were found to be resistant with AUDPC values ranged from 1 to 199. Response of ten lines was moderately resistant while five lines were categorized as moderately susceptible. Ten genotypes exhibited susceptible response against leaf rust with more than 600 AUDPC value. High values above 600 of AUDPC showed greater incidence of leaf rust on wheat plants while lower AUDPC values indicated resistance to leaf rust. Present research provided the resistant wheat lines to the breeders to incorporate in their breeding program against leaf rust.

- by Plant Protection
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- Fungal Plant Pathology
- by Srđan G Aćimović
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- Tree Physiology, Fungal Plant Pathology, Plant Bacteriology, Plant Protection

Chickpea is an economically important food crop, which is subjected to infection by a host of fungal, viral and bacterial pathogens. Thirty isolates of Pseudomonas fluorescens were isolated from the rhizosphere of Chickpea fields. These were tested against F. oxysporum in dual culture method. Among these, four (Pf 1, Pf 3, Pf 5 and Pf 8) isolates were showed bright fluorescence under UV light were further tested. All the cultural and biochemical studies confirmed them to be P. fluorescens. The isolates also showed positive response for siderophore production and plant growth promoting activity on Chickpea cultivar Bital 98. Among these isolates Pf 3 and Pf 5 shown significant results by increasing root length and shoot length. Both the Pf 3 and Pf 5 isolates were found significantly superior than other isolates in increasing the shoot length (12.7 cm) and root length (24.5 cm) over control. The isolates Pf 3 was recorded high vigor index (3830) followed by Pf 5 (3648). The least vigor index was recorded by Pf 1 (2631).

Charcoal rot incited by Macrophomina phaseolina is one of the major diseases of green gram and black gram in Pakistan
reducing yields up to 40%. As there are no long-term control strategies for this seed- and soil-borne pathogen, therefore,
in the present study, seven indigenous species of Trichoderma were evaluated for their in vitro and in vivo effectiveness
against M. phaseolina with the objective to identify alternatives to pernicious fungicides. All seven species of Trichoderma
significantly retarded the growth of M. phaseolina in vitro. Maximum reduction (79.63%) was observed with T. harzianum
followed by T. hamatum (76.3%) while T. pseudokoningii caused the minimum decrease (58.14%) in growth of the fungus.
Similarly, Trichoderma species had significant effects on number and size of sclerotia.M. phaseolina produced the minimum
number of sclerotia in the presence of T. hamatum followed by T. harzianum causing reductions of 69.5 and 66.84% over
control, respectively. The maximum reduction in size of sclerotia was caused by T. harzianum. The maximum plant
survival of green and black gram was obtained with T. harzianum followed by T. hamatum and T. viride. The maximum
individual germination of 86.67% was achieved with T. harzianum at a concentration of 2× 108 (propagules/ml), while the
minimum (33.33%) was recorded with T. pseudokoningii at 2× 104. Trichoderma concentrations also had significant effects
on plant survival, being the maximum at the highest concentration. The plant survival decreased as the concentrations of
the antagonists decreased showing a direct relationship between plant survival and concentrations.

- by Prof. Dr. Tariq Mukhtar
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- Fungal Plant Pathology

Sweet potato is a perishable food crop that is prone to weevil and fungal infection. Development of diseases due to fungal infection will lower its quality, reduce marketable price and sometimes the tubers are unable to sell. Crop losses due to diseases not only have bad implication to farmers, but also give threat to global food production and food security. This study was conducted to identify and document the insect and fungal pathogens associated with sweet potato diseases. For this purpose, infected tubers were collected, incubated and isolated before conducting the pathogenicity test. Ninety sweet potato weevils, Cylas formicarius had emerged and caused extensive damaged to the tuber. Following the sweet potato weevil infestation, four fungal isolates were successfully identified as Fusarium oxysporum (one isolate), Penicillium sp. (one isolate) and Aspergillus sp. (two isolates). All these isolates were pathogenic to sweet potato tubers with different level of diseases severity, ranged from 33.33% to 42.59%. Identification of weevil and fungal pathogen associated with sweet potato diseases is important to help in control strategy to avoid epidemic diseases that may cause loss of economic return. Besides that, farmers should applied integrated pest management control for continuous production of good quality sweet potato tuber.

- by Shamsul Bahri Abd Razak
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- Fungal Plant Pathology

Inoculation of faba bean seedling with freshly harvested teliospores of two isolates of Uromyces viciae fabae (Pers.) Schroet, resulted in successful germinating of telispores. Among the 12 faba bean cultivars tested using artificial inoculation, only 4 cultivars developed the five spore stages allowing the completion of the rust life cycle. Pycnia began to appear, as chlorotic flecks only, on the upper surfaces of the leaves 12-14 days after teliospore inoculation. Aecia formed only 10-12 days later on lower surfaces directly opposite to the pycnia formation. Aeciospores were collected and were used for inoculation of faba bean leaves. Uredia were formed 14-16 days later of aeciospores inoculation, under greenhouse conditions

Extensive leaf spot was observed on all leaves of young macadamia trees planted in new orchards in Queensland, Australia. The loss in photosynthetic ability of these trees may contribute to their demise and poor establishment compared to trees without symptoms. A survey of fungal leaf spots on macadamia trees in 20 commercial orchards in Queensland revealed two distinctive types of symptoms. Leaves showing circular dark brown spots with yellow halos (Type 1) and irregular dark brown spots (Type 2) were collected. Fungal isolates associated with the infected leaves were identified by morphological characteristics and DNA sequencing as Neopestalotiopsis clavispora for Type 1 spots and Colletotrichum siamense for Type 2 spots. Koch’s postulates were fulfilled for N. clavispora and C. siamense. Pathogenicity assays showed that both fungi caused severe leaf spots, which are identical to the respective field disease symptoms. In order to clearly characterise them, the two leaf spots were named as Pestalotiopsis leaf spot (Type 1 spots) and Colletotrichum leaf spot (Type 2 spots). This is the first report of N. clavispora and C. siamense causing leaf spots in macadamia in Australia.

- by Victor Galea and +1
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- Molecular plant pathology, Fungal Plant Pathology, Plant Pathology
- by Mustafa N Owaid
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- Fungal Plant Pathology, Viruses, Medical Bioengineering, Plant Pathology

Field studies were conducted to evaluate the comparative efficacy of six systemic and four non-systemic fungicides against early blight of tomato caused by Alternaria solani (Ellis and Martin). The experiments conducted during Kharif 2014 to study effect of some promising fungicides found under in vitro studies as foliar sprays against early blight of tomato. Three foliar sprays of at 15 days interval with Difenoconazole 25 EC was the most effective fungi toxicant reducing the disease incidence to 23.48 per cent from 61.23 per cent, unsprayed check. The other fungicides in order of their decreasing efficacies were Flusilazole 40 EC >Hexaconazole 5 EC >Mancozeb 75 WP. Propineb 70 WP proved least efficacious among the test fungitoxicants reducing the disease incidence to 43.70 per cent from 61.23 per cent, unsprayed check. Similarly Difenoconazole 25 EC again proved most effective fungitoxicant in case of disease intensity reducing the disease intensity to 16.39 as against 41.31 per cent observed in unsprayed check. The other fungicides in order of their decreasing efficacies were Mancozeb 75 WP >Flusilazole 40 EC >Hexaconazole 5 EC. Propineb 70 WP proved least efficacious among test fungi toxicants reducing the disease intensity to 24.11 per cent. Difenoconazole 25 EC gave the highest disease control of 61.67 and 60.32 per cent in case of disease incidence and disease intensity respectively while the least per cent disease control of 43.70 and 41.63 per cent respectively was given by Propineb 70 WP.

Olive is the most widely grown fruit tree in Jordan; it is annually attacked by the olive fruit fly, Bactrocera oleae (Rossi), whose larvae usually cause great economic losses in fruit yield. Alternaria solani, Aspergillus niger, Cladosporium herbarum, Fusarium solani, Penicillium digitatum, P. italicum and Rhizopus stolonifer were found associated with the fly infestation with a sample frequency ranging from 6.7-33.3%. Penicillium digitatum was the most dominant species. All molds were vulnerable for a hot water treatment at 50 and 70ºC as indicated by their low spore germination and colony-forming unit except for P. digitatum and P. italicum which were the most heat-tolerant. When the olive oil was inoculated with pure cultures of these molds, the mold fungi were able to colonize olive oil. Rhizopus stolonifer was the greatest colonizer and besides Alternaria solani, both had obviously reduced the oil peroxide value over the control without greatly affecting the oil free fatty acid content.

- by Muwaffaq Karajeh
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- Fungal Plant Pathology
- by Subrahmaniam Nagarajan
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- Fungal Plant Pathology, Phyto-epidemiology

Defensins are cysteine-rich cationic antimicrobial peptides contributing to the innate immunity in
plants. A unique gene encoding a highly cationic bi-domain defensin MtDef5 has been identifed
in a model legume Medicago truncatula. MtDef5 consists of two defensin domains of 50 amino
acids each linked by a 7-amino acid peptide. It exhibits broad-spectrum antifungal activity against
flamentous fungi at submicromolar concentrations. It rapidly permeabilizes the plasma membrane
of the ascomycete fungi Fusarium graminearum and Neurospora crassa and induces accumulation of
reactive oxygen species. It is internalized by these fungi, but uses spatially distinct modes of entry
into these fungi. It co-localizes with cellular membranes, travels to nucleus and becomes dispersed in
other subcellular locations. It binds to several membrane-resident phospholipids with preference for
phosphatidylinositol monophosphates and forms oligomers. Mutations of the cationic amino acids
present in the two γ-core motifs of this defensin that eliminate oligomerization also knockout its
ability to induce membrane permeabilization and fungal growth arrest. MtDef5 is the frst bi-domain
plant defensin that exhibits potent broad-spectrum antifungal activity, recruits multiple membrane
phospholipids and forms oligomers in their presence. These fndings raise the possibility that MtDef5
might be useful as a novel antifungal agent in transgenic crops.

- by Siva Velivelli
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- Plant Ecology, Plant Biology, Plant Tissue Culture, Biocontrol of Plant Pathogens

Plant growth promoting rhizobacteria (PGPR), are associated with roots, found in the rhizosphere and can directly or indirectly enhance the plant growth. In this study soil was collected from rhizosphere of chickpea fields of different areas of Rawalpindi division of Pakistan. PGPR were isolated, screened and characterized. Eight isolates of rhizobacteria (RHA, RPG, RFJ, RC, RTR, RT and RK) were isolated from Rawalpindi division and were characterized. The antagonistic activity of these PGPR isolates against root infecting fungi (Fusarium oxysporum and Verticillium spp.,) was done and production of indole acetic acid (IAA), siderophore and P-solubilization was evaluated. The isolates RHA, RPG, RFJ, RC, RRD and RT were found to be positive in producing siderophore, IAA and P-solubilization. Furthermore, most of the isolates showed antifungal activity against Fusarium oxysporum, and Verticillium spp. The rhizobacterial isolates RHA, RPG, RFJ, RC, RRD, RTR, RT and RK were used as bio-inoculants that might be beneficial for chickpea cultivation as the rhizobacterial isolates possessed the plant growth promoting characters i.e. siderophore, IAA production, phosphate solubilization. In in vitro tests, Pseudomonas sp. and Bacillus spp. inhibited the mycelial growth of the fungal root pathogens. The isolates (RHA and RPG) also significantly increased (60-70%) seed germination, shoot length, root length of the chickpea. The incidence of fungi was reduced by the colonization of RHA and RPG which enhanced the seedling vigor index and seed germination. The observations revealed that isolates RHA and RPG is quite effective to reduce the fungal root infection in greenhouse, and also increases seed yields significantly. These rhizobacterial isolates appear to be efficient yield increasing as well as effective biocontrol agent against fungal root pathogen.

Leaf spot disease caused by Alternaria alternata is one of the major diseases of Aloe vera and is prevalent
in almost all the Aloe vera growing countries. The present study was carried out to test efficacy of antagonist and
fungicides in inhibiting the pathogen under in vitro condition. Among the five strains of Trichoderma harzianum viz.
Th-2, Th-4, Th-6, Th-9 and Th-12 tested. Maximum per cent inhibition in mycelial growth was recorded in Th-12 (30%)
followed by Th-2 (25) while minimum inhibition (16.25) was observed Th-9. Out of five fungicides tested in vitro,
Hexaconazole and Carbendazim was found to be highly effective showing complete inhibition at 100 ppm. Whereas,
minimum inhibition (7.50) was recorded in Propiconazole.

- by Dr. K. K . SAINI
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- Fungal Plant Pathology

Shaban, W.I.A. and Abdelssalam, M.M.M. 2009. Evaluation of combining ability of some agronomic traits and susceptibility to Fusarium wilt in watermelon hybrids. Tunisian Journal of Plant Protection 4: 15-28. Four lines, two testers of watermelon and their 8 F1 hybrids which were developed through line × tester mating design, were used to study the general and specific combining ability and heterosis for six growth traits and resistance to Fusarium wilt. Biochemical parameter such as phenolic content of healthy and infected plants was analyzed. Line 480 was good combiner for average fruit weight, while tester Giza 21 was good combiner for number of fruits per plant. All crosses were non-significant for all traits studied except PI612145 × Giza 21; it was significant with positive value for rind thickness trait. With respect to heterosis effects, cross 480 × Giza 21 gave earliest female flower over mid-parent, crosses Giza 21 × PI612145 and 424 × 96604005, whereas 480 × Giza 21 gave highest values with significant effect for fruit yield per plant, average fruit weight and number of fruits per plant, respectively. Resistant genotypes were recorded for line 96604005 and crosses 480 × 96604005 and 480 × Giza 21 which produced the highest percentage of survived plants and have a strong increase in phenolic content production in addition to production of high aerial part dry weight. Resistance trait showed increasing in F1 genotypes coming from crosses between high susceptible line 96604003 and testers 96604005 and Giza 21 (resistant and moderate resistant, respectively). In addition, crossing between moderate resistant line 480 and testers 96604005 and Giza 21 produced resistant F1 genotypes.

- by Waleed I Shaban
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- Plant Breeding, Fungal Plant Pathology

Fungal spores are a significant fraction of the atmospheric bioparticles (bioaerosols) and many species are capable of inducing the production of specific immunoglobulin E (IgE), aggravating the clinical symptoms of allergic respiratory diseases in sensitized individuals. The aim of this work was to evaluate the distribution of potentially allergenic Pleosporales spores in two locations with different urbanization indexes, characterizing its seasonal pattern. The seasonal distribution of several spore types belonging to the Pleosporales (Alternaria, Drechslera, Epicoccum, Paraphaeosphaeria, Pithomyces, Pleospora and Stemphylium) in Amares (rural area) and Porto (urban area) was continually studied from January 2005 to December of 2007, using Hirst-type volumetric spore traps. Alternaria was the most abundant fungal spore type found in the atmosphere of Amares and Porto. This fungal type, together with Drechslera, Epicoccum, Pithomyces and Stemphylium, was mainly present during summer. Nevertheless, Leptosphaeria, Pleospora and Venturia spores were detected during winter and spring, while Paraphaeosphaeria spores were also observed during summer and autumn. These different seasonal patterns were responsible for the expansion of the exposure period for the Alt a 1 allergen. The concentration of the studied spore types was higher in the rural area than in the urban one, with exception for Pleospora and Drechslera. According to the correlations with meteorological factors, the selected fungal spores can be divided into two groups: (i) Alternaria, Drechslera, Epicoccum, Pithomyces and Stemphylium presented positive correlations with temperature and negative correlations with relative humidity and rainfall; (ii) Leptosphaeria, Paraphaeosphaeria, Pleospora and Venturia presented a contrary behavior. Usually, the occurrence of the Alt a 1 allergen has been associated with the presence of airborne Alternaria spores; the present work follows the seasonal distribution of other fungal spore species known to contain this molecule. The widespread occurrence of Alt a 1 plays an important role in the incidence and aggravation of allergic disorders.

- by L. Delgado
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- Fungi, Allergy, Fungal Plant Pathology

Onion (Allium cepa L.), an important edible species of genus Allium cultivated both in rabi and kharif season in Indian Punjab. It is planted directly by seeds or by bulb sets for table purpose and seed production. Onion is reported to be attacked by many viruses among these, Onion yellow dwarf virus (OYDV), Leek yellow stripe virus(LYSV),Garlic common latent virus, Shallot latent virus and Garlic virus X have been reported from India. These virus(es) attack onion either singly or in combination and causes severe losses. Present study was carried out to study the effect of virus (es) on symptoms and yield parameter. Serological and molecular detection from infected samples confirmed the association of OYDV and LYSV in onion. The virus symptoms associated with onion were categorized in three category (i) Symptomless plant with flattened older leaves (ii) Yellow stripping on leaves, flattening and stunting of plant (iii )Severe twisting, thinning, partial and complete yellowing of leaves, stunting of plant and such plant did not bolt. The first category symptoms are more prominent in crops raised by seeds, whereas, the other two categories are prominent in crop raised by bulb sets. Growth parameter such as plant height, leaf diameter, number of leaves were recorded both in infected and healthy control. Severe reduction in growth parameter i.e. 16.89, 12.24, 1.50 per cent reduction in height of plant, no of leaves per plant and diameter of leaves, respectively, were recorded over healthy control. Yield parameter viz. bulb weight, seed weights were also recorded. Reduction in bulb weight by 56.16% and seed weight by 7.50% over healthy control was observed. This data revealed that virus complex of onion is responsible for drastic reduction in bulb and seed production in north-western part of India.

- by Irfan khan
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- Mycology and Plant pathology, Plant Virology, Plant Molecular Virology, Plant Virus

To optimize the number and timing of trunk injections for season-long control of apple scab (Venturia inaequalis), we evaluated 1-2 and 4 seasonal and cross-seasonal injections of potassium phosphites and synthetic fungicides and quantified residues in leaves and fruit. Phosphites accumulated in the canopy at the highest concentrations, aligned well in time with scab suppression, and gave better leaf scab control of 41.8-73.5% than propiconazole (16.9-51.5%) or difenoconazole + cyprodinil (5.4-17.4%). More injections of phosphites controlled leaf scab better than fewer (23.7% vs. 48.2%), and more fungicide injections resulted in 21.9-51.1% better leaf scab control than fewer. Leaf scab control with phosphites was 3.2-13.9% better with 4 cross-seasonal compared to 4 seasonal injections, while 1-2 seasonal compared to 1-2 cross-seasonal injections improved scab control for 4.2-22.1%. On shoots, injected phosphites provided comparable or for 4.4-10.5% and 22.3-41.4% better scab control than spray standards. On fruit, injected phosphites slightly improved control compared to sprayed phosphites or the sprayed fungicide standard (33.4-40.8%). Two seasonal injections of phosphites controlled shoot scab 5.7% better than 9 spray applications. Five sprays of difenoconazole + cyprodinil controlled scab better than their injections. Fruit residues of phosphites reached 2.8 ppm and declined in all treatments except in 2 seasonal injections and phosphite sprays. Cyprodinil and difenoconazole fruit residues reached 0.02 and 0.07 ppm and declined sharply towards the end of the season. These were far below the USA, Codex, and EU MRL-s of 1, 0.8 and 0.5 ppm for difenoconazole, and 1.7, 2 and 1 ppm for cyprodinil, respectively.

The present investigation was carried out to study the effect on seed germination and seedling vigour by seed borne fungi of pea (Pisum sativum L.).During the present study different culture filtrate effects of seed borne fungi showed reduction in seed germination and seedling vigour. The percent inhibition in germination was maximum with the culture filtrate of Fusarium solani (93.46%) and the minimum percent inhibition was in case of Aspergillus and pencillum spp. The reduction in plumule length was minimum in culture filtrate of A. flavus. The decrease in plumule length (mm) was maximum in case of culture filtrate of R.solani (11.01) and F. moniliforme (10.33) as compared to control. Root growth in Pisium sativum L .was sensitive to culture filtrate of pathogenic fungi. All filtrates reduced root length with variable phytotoxic potential among them significantly. The minimum reduction in radicle length was recorded with culture filtrate of F. oxysporum (9.11mm) as compared to control (67.53mm). The seedling vigour is less affected by A. flavus and pencillum spp.

- by Khursheed Aalum
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- Fungal Plant Pathology

Banana fruit crop is one of the most valued commodities in the agriculture export industry. Fusarium wilt
disease also well known as the Panama disease has been plaguing this industry since 1919. Its causal agent,
Fusarium oxysporum f. sp. cubense (Foc) is a highly destructive and a variable pathogen for which no effective
control measure exists. The durability of a sustainable management strategy depends on the pathogen
population structure. In this study 55 Foc isolates from nine different banana farms of district Thatta of Pakistan
were investigated for morphological and genetic diversity. The Foc isolates under study produced septate to
unseptate microconidia, monophialides, sickle shaped 3-5 septate macroconidia with basal foot, and globose
chlamydospores present singly, in pairs or in chains. Pigmentation in colonies varied from white, purple, salmon
pink to peach. The optimum temperature for colony growth and sporulation was 25°C. The growth rate among
the Foc isolates ranged from 6 to 8 days. Foc isolates mostly exhibited good to medium sporulation rate. No
statistical correlation was observed between growth rate and sporulation potential. Out of six, only five ISSR
primers amplified and generated 42 scorable bands ranging from 350bp to 2.5Kb in sizes and 40 were
polymorphic (83.4% to 100%). Structure software revealed a genetic admixture population structure with low
level of variation among the isolates. UPGMA dendrogram clustered Foc population into two major clades. The
present study reports low levels of diversity in Pakistani Foc isolates at both morphological and genetic level.

- by Alia Mushtaq
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- Molecular plant pathology, Fungal Plant Pathology

Present exploration is strictly carried out for selective species of Cleome viz. Cleome chelidonii L.f., C. speciosa Raf., C. gynandra L., C. simplicifolia (Camb.) Hook f. & Thoms and C. viscosa L. All these species are herbs growing at same locality but in different soil types as Cleome chelidonii grows vigorously in moist places and also in the rocky regions, while C. simplicifolia and C. viscosa grow luxuriantly in the black soil in rainy season. Cleome simplisifolia has very short life cycle up to 3-4 months only. C. viscosa and C. gynandra grow throughout the year but more vigorously during rainy season. C. gynandra grows predominantly in waste places along waste water. C. speciosa is cultivated species growing widely in shadow places in the red soil particularly during rainy season. It is famous for its beautiful showy inflorescence and hence cultivated in gardens. Several researchers have evidences that stomatal densities change in response to changing atmospheric levels of c...

- by B. Karadge
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- Climate Change, Ethnobotany, Conservation Biology, Taxonomy

Cherry leaf spot disease, caused by Blumeriella jaapii (Rehm) Arx., is an increasing concern to nursery producers of ornamental cherry in the southeastern United States. Spores were trapped starting in late March before symptoms were observed in the field, which indicates that leaf debris from diseased trees are an important source of primary inoculum. Previously infected trees of six cultivars ('Kwanzan', 'Yoshino', 'Okami', 'Snowgoose', 'Autumnalis' and 'Akebono'), which were overwintered in a controlled environment protected from airborne spores, developed disease symptoms in late spring, indicating that dormant buds may also be a source of primary inoculum. Because ornamental cherry trees are propagated by budding and cuttings, disease management should incorporate cultural practices that focus on propagation from disease-free trees and fungicide applications beginning at petal drop to protect emerging leaves.

The disease on leaves was characterized by the appearance of small, reddish to dark brown pinpointed spots measuring approximately 3 mm in size, with angular to irregular margins, and as the spots grew, they become more or less circular in outline, with reddish brown to black centers and were surrounded by a yellowish halo which on coalescing formed irregular necrotic patches. Severe infection resulted in premature defoliation. Small, sunken, circular, black spots, averaging 6 mm in size surrounded by reddish brown margins, embedded with dark brown to black acervuli releasing creamy white spore droplets under moist conditions. Severely infected fruits were roughened and developed cracks were the characteristic disease symptoms observed on fruit. The pathogen constantly associated with the disease was isolated. The pathogen on potato dextrose casein hydrolysate thiamine agar medium produced compact, glistering, dull white to reddish brown cottony mycelial mat after 45 days of incubation at 22±1°C. The morphological characters of the pathogen associated with the disease were studied both on host (in vivo) as well as on after culturing on potato dextrose agar medium incorporated with casein hydrolysate thiamine (in vitro). On the host the hyphae were branched, smooth, thick walled, septate, hyaline and measured 8.25-8.75 µm in width averaging 8.48 µm, the size of the conidia ranged from 14.46-20.68  9.42-12.46 µm. with an average size of 17.57  10.94. From culture on potato dextrose casein hydrolysate thiamine agar medium the fungus exhibited compact, dull, white, glabrous, glistering cottony growth. The white colour of the fungal colony finally changed to reddish brown after 30 days of incubation at 22±1°C. The hyphae were hyaline, smooth, thick walled, branched, septate, and measured 8.54 to 8.98 µm in width averaging 8.76µm, the conidial size ranged from 16.36-22.70 µm in length and 10.37-14.65 µm in width averaging (19.5612.51 µm).

European forests host a diversity of tree species that are increasingly threatened by fungal pathogens, which may have cascading consequences for forest ecosystems and their functioning. Previous experimental studies suggest that foliar and root pathogen abundance and disease severity decrease with increasing tree species diversity, but evidences from natural forests are rare. Here, we tested whether foliar fungal disease incidence was negatively affected by tree species diversity in different forest types across Europe. We measured the foliar fungal disease incidence on 16 different tree species in 209 plots in six European countries, representing a forest-type gradient from the Mediterranean to boreal forests. Forest plots of single species (monoculture plots) and those with different combinations of two to five tree species (mixed species plots) were compared. Specifically, we analyzed the influence of tree species richness, functional type (conifer vs. broad-leaved) and phylogenetic diversity on overall fungal disease incidence. The effect of tree species richness on disease incidence varied with latitude and functional type. Disease incidence tended to increase with tree diversity, in particular in northern latitudes. Disease incidence decreased with tree species richness in conifers , but not in broadleaved trees. However, for specific damage symptoms, no tree species richness effects were observed. Although the patterns were weak, susceptibility of forests to disease appears to depend on the forest site and tree type.

- by Bogdan Jaroszewicz and +1
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- Functional Ecology, Forest Ecology, Fungal Plant Pathology, Trees
- by Aamna Ishaq
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- Fungal Plant Pathology

Seedling production under smallholder farming systems can be negatively affected by both abiotic and biotic factors. Seedling damping-off caused by Rhizoctonia solani is one of the major biotic factors which causes significant yield reduction. Management is mainly based on the application of synthetic fungicides and cultural practices. However, both methods have limitations which result in their inefficiency. Several studies have reported on the use of plant extracts and biological control to manage plant diseases. The aim of this study was to formulate an effective and practical approach to manage tomato seedling dampingoff using extracts of Monsonia burkeana and Moringa oleifera and a biological control agent Trichoderma harzianum. The efficacy of both extracts was investigated under laboratory conditions to determine the most suppressive concentration to R. solani growth. Methanolic extracts from both plants significantly suppressed pathogen growth at different concentrations. M....

- by Mapotso Kena
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- Biology, Medicinal Plants, Fungi, Fungal Plant Pathology

Beauveria bassiana is the most widely studied entomopathogenic fungi which have drawn attention worldwide not only as an insect-pest control but also as management of plant pathogenic fungi and bacteria along with their plant growth promotion activities. Mechanisms of plant disease suppression by Beauveria sp. involve antibiosis, mycoparasitism, competition, endophytism and induced systemic resistance. Moreover, production of wide array of volatile organic compounds, hydrolytic enzymes (chitinases, amylases, lipases, cellulases, caseinases and proteases) and various secondary metabolites (beauvericin, bassinolide, beauvolide, beauviroloide, oosporein, bassianin and tenellin) triggers its antifungal and antimicrobial properties against various plant pathogens. Beauveria sp. have been reported to suppress diseases caused by various foliar and soil borne phytopathogens belonging to Oomycetes

- by Lipa Deb
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- Fungal Plant Pathology, Beauveria bassiana, Antagonism

Citrullus colocynthis, belonging to the family of cucurbitaceae. It is a xerophytic desert plant, widely used for its medicinal purpose. In tribal areas it is used for the treatment of constipation, oedema, bacterial infection, cancer, diabetes and abortifacient. Present study is based on developing a protocol for plantlet regeneration from the nodal segment. The sterilized explants were inoculated in different concentrations of cytokinins and auxins. Among the various treatments, MS (1962) medium supplemented with BAP (2.0mg/l) gave the best shooting culture establishment. For shoot elongation MS medium supplemented with IBA (0.1 mg/l) was found to be best. In vitro elongated shoots rooted on MS medium supplemented with IBA (0.1 mg/l). The plantlets were hardened, acclimatized and transplanted in the field, where they showed 60% survival rate.

- by Shikha Roy
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- Ethnobotany, Photosynthesis, Bioremediation, Fungal Plant Pathology

In the present study 28 localities of Telangana and Andhra Pradesh were surveyed (2001-2002) for the occurrence of fungi from various substrates like litter, wood, bark, humid soil, leaves, decaying dead leaves, plant debris, twigs and others. Altogether 66 fungal species were isolated and among these anamorphic fungi formed the bulk of fungal flora. Periconiella cocoes, Pseudobotrytis bisbyi, Ramichloridium musae and Saccardea echinocephala are the new additions to the fungi of Telangana and Andhra Pradesh. Some fungi like Ganoderma sps. and Memnoniella sps. have already been established for their biotechnological importance.