THE publication, in 1926, of the monograph “The Aspergilli” by Thorn and Church was a landmark in the taxonomic study of this important genus of moulds. The fact that a re-working of the genus after twenty years has necessitated no fundamental change in classification is the best evidence of the sound scholarship which went to the writing of the monograph. Nevertheless, its very excellence gave other workers confidence, not only in identifying Aspergilli, but also in describing new species, with the result that a fair amount of new material has accumulated during the intervening years. A Manual of the Aspergilli By Charles Thom Kenneth B. Raper. Pp. ix + 373. (London: Bailliere, Tindall and Cox, 1945.) 38s. 6d.

A Manual of the Aspergilli

Background Extensive and growing use of different chemical pesticides that affect both the environment and human health raises a need for new and more suitable methods to deal with plant pathogens. Nanotechnology has enabled the use of materials at the nanoscale with exceptional functionality in different economic domains including agricultural production. This study aimed to evaluate antifungal potential of selenium nanoparticles (SeNPs) and silver nanoparticles (AgNPs) stabilized with different surface coatings and characterized by different surface charge on plant pathogenic fungi Macrophomina phaseolina, Sclerotinia sclerotiorum and Diaporthe longicolla. Results AgNPs were coated with three different stabilizing agents: mono citrate (MC-AgNPs), cetyltrimethyl ammonium bromide (CTAB-AgNPs) and polyvinylpyrrolidon (PVP-AgNPs). SeNPs were coated with poly-l-lysine (PLL-SeNPs), polyacrylic acid (PAA-SeNPs), and polyvinylpyrrolidon (PVP-SeNPs). Seven different concentrations (0.1, 0.5, 1, 5, 10, 50 and 100 mg L-1 ) of nanoparticles were applied. All AgNPs and SeNPs significantly inhibited the growth of the tested fungi. Among the tested NPs, PVP-AgNPs showed the best inhibitory effect on the tested plant pathogenic fungi, especially against S. sclerotiorum. The similar inhibition of the sclerotia formation was observed for S. sclerotiorum treated with PLL-SeNPs. Conclusion Obtained results provides new insights on fungicide effect of AgNPs and SeNPs stabilized with different coating agents on different plant pathogens. Further work should focus on detailed risk/benefit ratio assessment of using SeNPs or AgNPs in agriculture taking into account whole agroecosystem. © 2020 Society of Chemical Industry.

Antifungal activities of silver and selenium nanoparticles stabilized with different surface coating agents.

Maize is an important food security crop along with rice and wheat globally. Losses caused by biotic stresses in maize are substantial and Curvularia leaf spot is important among them. Further management of Curvularia leaf spot is done primarily through chemicals, therefore an attempt was made to evaluate the efficacy of com- monly used systemic and non-systemic fungicides against the pathogen, and most susceptible growth stage for disease development was identified. In vitro evaluation of four systemic and four non-systemic fungicides was done at different concentrations, for checking the growth of pathogen. The data revealed that Carboxin (at 25 ppm) completely inhibited growth of pathogen. Further among non-systemic fungicides treatment of Mancozeb showed maximum growth inhibition (98. 24% at 200 ppm). Under glass house conditions mancozeb was found to be more effective than Carboxin for controlling the disease severity. Further to determine the time of application of fungicides, developmental stage most susceptible to Curvularia lunata was studied. Three growth stages (Knee height stage, Silking stage and Tasseling stage) were compared. Maximum disease index and severity was found at Silking stage (47% and 53.75%, respectively) followed by Tasseling stage (42.5% and 18.4%, respectively) and Knee height stage (37% and 30%, respectively), indicating that the disease progresses with the maturity of the plant and is maximum at the Silking stage. Results suggest that susceptible maize varieties may give higher yield with the optimisation of the time of application of the fungicides and higher economic and environmental gains can be achieved with judicious use of fungicides.

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Determination of susceptible growth stage and efficacy of fungicidal management of Curvularia leaf spot of maize caused by Curvularia lunata (Wakker) Boedijn

Eucalyptus cultivation has expanded considerably in Brazilian systems, leading to the current search for technologies to optimize growing conditions and the production of seedlings in nurseries. Based on the understanding that the development of tree species such as Eucalyptus sp. can be influenced by endophytic fungi that act directly as plant growth-promoting species, cloned seedlings of Eucalyptus grandis x Eucalyptus urophylla hybrids grown from minicuttings we stimulated with three species of endophytic fungi and the effects of inoculation on seedling growth was evaluated. Strains of Trichoderma sp., Fusarium sp. and Papulaspora sp. were forced to colonize the root system of the plants, which were continuously maintained under protected cultivation. Inoculation of the symbionts had positive effects on stem length, stem diameter and the fresh and dry biomass of the treated plants. Non-inoculated plants presented a shorter stem length than the plants treated with any of the endophytic species. The cloned seedlings inoculated with Trichoderma sp. exhibited the greatest stem measurements at 120 days after transplanting. The seedlings inoculated with Fusarium sp. displayed a greater number of leaves than the other seedlings as well as greater amounts of fresh and dry biomass. The authors also conducted quarterly evaluations of the increment in seedling growth promoted by the inoculants, which were more effective in the early stages, up to 60 days after transplanting. Keywords: Inoculants, microorganisms, minicutting, tree species

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Growth promotion mediated by endophytic fungi in cloned seedlings of Eucalyptus grandis x Eucalyptus urophylla hybrids

Four antagonistic fungi Aspergillus flavus Link, A. fumigatus Fresenius, A. niger van Tiegh. and Trichoderma viride Pers. were isolated from field soil of Rauwolfia serpentina by serial dilution method and selected to evaluate their antagonistic potentiality against Colletotrichum gloeosporiodes (Penz.) Sacc, the causal agent of anthracnose of Rauwolfia serpentina (L.) Benth. ex Kurz following dual culture colony interaction, volatile and non-volatile metabolites. In dual culture method Trichoderma viride showed maximum (84.28%) inhibition of test fungi followed by Aspergillus niger (77.39%), A. fumigatus (43.71%) and A. flavus (29.32%). Volatile metabolites of T. viride showed higher (77.64%) inhibition of test fungi followed by A. flavus (75.58%), A. fumigatus (60.88%) and A. niger (58.23%). Non-volatile metabolites of antagonistic fungi showed that A. flavus showed (94.42%) inhibition of test fungus followed by T. viride (90.90%), A. niger (86.13%) and A. fumigatus (73.73%). Aspergillus flavus, A. niger and T. viride may be exploited commercially as a biocontrol agent against anthracnose disease of R. serpentina. \nDhaka Univ. J. Biol. Sci. 28(2): 219-226, 2019 (July)

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Antagonistic potential of soil fungi against Colletotrichum gloeosporiodes (Penz.) Sacc., the causal agent of anthracnose of Rauwolfia serpentina (L.) Benth. ex Kurz

Antagonistic potentials of seven rhizoshere soil fungi viz., Aspergillus flavus Link., A . fumigatus Fresen., A . niger Tiegh., A . terreus Thom., Penicillium sp., Trichoderma harzianum Refat. and T . viride Pers. were tested in opposition to six pathogenic fungi viz., Colletotrichum sp., Curvularia lunata, Fusarium moniliforme , F . oxysporum , F . semitectum and Phomopsis sp. isolated from different leaf spots and fruit rots of brinjal. Out of seven soil fungi, Trichoderma harzianum was found most effective to control the growth of all the test fungi in the study of colony interactions and effects of volatile and non-volatile metabolites. This fungus may be exploited commercially to biocontrol the diseases. DOI: http://dx.doi.org/10.3329/bjb.v43i2.21675 Bangladesh J. Bot. 43 (2): 213-217, 2014 (September)

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Antagonistic potential of rhizosphere fungi against leaf spot and fruit rot pathogens of brinjal

DOI: http://dx.doi.org/10.3329/dujbs.v23i1.19833 Dhaka Univ. J. Biol. Sci. 23 (1): 97-99, 2014

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Evaluation of fungicides on fungi associated with fruit rots and leaf spots of brinjal

The incidence of anthracnose disease was observed lowest in December (10.87%) and highest in July (80.50%) at the three selected betel vine fields of Shalon village in Moulvibazar district. The young stems were found more prone to attack than the old ones. Pathogenicity test showed Colletotrichum dematium and C. gloeosporioides produced characteristic disease symptoms on betel stems. Among them C. dematium is a new document as a pathogen of anthracnose of betel vine. Out of five fungicides, complete inhibition of both the pathogens in vitro occurred with corozole EC (25% propiconazole), folicur EC (25% tebuconazole) and trooper WP (75% tricyclazole). Among the four antagonistic fungi, Penicillium sp. showed more antagonistic potentiality against the pathogens. DOI: http://dx.doi.org/10.3329/dujbs.v23i2.20092 Dhaka Univ. J. Biol. Sci. 23(2): 127-133, 2014

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KS Hossain

Papers

Antagonistic potential of rhizosphere fungi against leaf spot and fruit rot pathogens of brinjal

Evaluation of fungicides on fungi associated with fruit rots and leaf spots of brinjal

Anthracnose of betel vine and its in vitro management