scholarly journals Occurrence of Postharvest Fungal Rots of Sweet Potato (Ipomoea batatas (L) Lam.) in Southwest Nigeria and their Control with Sawdust Extracts

Author(s):  
F. Beckley ◽  
S. O. Awoyemi

A study was conducted in three agroecological zones (AEZs) of Southwest, Nigeria to evaluate the incidence and pathogenicity of postharvest fungal rots of sweetpotato and their control with extracts of sawdust from some tropical trees.  Survey of rotted tubers was conducted in 18 markets across the three AEZs: humid rainforest (HF), derived savannah (DS), and southern guinea savannah (SGS). Fungi associated with rotted tubers were isolated, identified and their pathogenicity determined. In vitro fungitoxicity of Anogeissus leiocarpus, Gmelina arborea and Cola nitida sawdust extracts were assessed in an experiment laid out in a Completely Randomized Design (CRD) with 3 replicates. Six fungi species found to be associated with rot on tubers were Botryodiplodia theobromae, Rhizopus stolonifer, Aspergillus niger, Trichoderma viride, Penicillium oxalicum and Fusarium oxysporum. Highest (35%) rot incidence was observed in HF zone with R. stolonifer as the most prevalent. Botryodiplodia theobromae was most prevalent (68.75%, 54.54%) in SGS and DS zones respectively. All the six isolated fungi were pathogenic to sweetpotato but induced varying levels of rot severity. Botryodiplodia theobromae, R. stolonifer or A. niger induced complete (100%) rot of inoculated tubers. Sawdust extracts reduced mycelial growth of test pathogens at three sawdust concentrations (50 g/L, 75 g/L and 100 g/L) tested. Inhibition of fungal growth increased with extract concentration. Anogeissus leiocarpus sawdust extract at 100 g/L exhibited highest range of mycelial growth inhibition (8.80 - 73.0%) across tested pathogens. Gmelina arborea sawdust extract at 100 g/L significantly inhibited (p<0.05) mycelial growth of B. theobromae, P. oxalicum and T. viride while C. nitida exhibited strong fungitoxicity to F. oxysporum at 100 g/L. Application of the sawdust extracts at 50 g/L, 75 g/L and 100 g/L concentrations has the potential to minimize postharvest fungal rot of sweetpotato.

2010 ◽  
Vol 2 (3) ◽  
pp. 72-76 ◽  
Author(s):  
Bilal Ahmad PADDER ◽  
Prem Nath SHARMA ◽  
Renu KAPIL ◽  
Anju PATHANIA ◽  
Om Prakash SHARMA

Three bioagents (Trichoderma viride, T. harzianum and Gliocladium virens) and five biopesticides (Achook, Neemgold, Wannis, Spictaf and Neemazal) were evaluated under in vitro and in vivo conditions against Colletotrichum lindemuthianum. All the three antagonistic fungi caused significant inhibition of mycelial growth, maximum being with T. viride (69.21%) followed by T. harzianum (64.20%). Among the biopesticides tested at four concentrations, Wanis applied @ 1000 ?l/ml caused maximum inhibition of 82.12 per cent followed by Spictaf (52.85%). T. viride and Wanis @ 1000 ?l/ml were most effective in reducing the seed borne infection. Integration of bioagents with Bavistin showed that disease can be effectively managed with seed dressing either with Bavistin or biopesticide followed by foliar treatment with fungicide or biopesticide.


Author(s):  
Kevison Romulo da Silva França ◽  
Flavia Mota de Figueredo Alves ◽  
Tiago Silva Lima ◽  
Alda Leaby dos Santos Xavier ◽  
Plínio Tércio Medeiros de Azevedo ◽  
...  

This study evaluates the in vitro effects of Lippia gracilis essential oil on the mycelial growth of phytopathogenic fungi. Experiments were carried out using a completely randomized design to assess the effects of eight treatments. Five replicates were evaluated for each experimental group. The essential oil was incorporated into the potato dextrose culture medium and poured into Petri dishes. Treatments were comprised of different concentrations of the oil (0.0125, 0.025, 0.05, 0.1, and 0.2%), a negative control (0.0%), and two positive controls (commercial fungicides). The plates were inoculated with fungi including Colletotrichum gloeosporioides, C. musae, C. fructicola, C. asianum, Alternaria alternata, A. brassicicola, Fusarium solani, F. oxysporum f. sp. cubense, and Lasiodiplodia theobromae and were incubated for seven days at 27 ± 2°C. The following variables were measured to verify the differences observed among treatments: percentage of mycelial growth inhibition and index of mycelial growth speed. All concentrations of L. gracilis oil inhibited the mycelial growth of the fungal species evaluated. The complete inhibition was observed between concentrations of 0.0125 and 0.1%. Treatment with oil inhibited fungal growth with similar, or even greater, efficiency than commercial fungicides.. We recommend the development of in vivo tests to verify whether L. gracilis essential oil can protect against fungal disease in live plants.


Author(s):  
Akhilesh Kumar Kulmitra ◽  
Neha Sahu ◽  
V.B. Sanath Kumar ◽  
Thejesha A. G. ◽  
Amlan Ghosh ◽  
...  

The five different bio-agents viz., Trichoderma viride, T. harzianum, T. virens, Pseudomonas fluorescens and Bacillus subtilis were evaluated against Pyricularia oryzae at four and eight days after incubation through dual culture technique. Among the five different bio-agents, highest per cent inhibition of mycelial growth of fungus was recorded in T. virens i.e. 67 per cent and 70 percent after four and eight days after incubation respectively with mean of 68.5 per cent followed by Trichoderma viride with the inhibition of 61 and 63 per cent respectively with mean of 62 per cent. The Pseudomonas fluorescens did not show any inhibition of mycelial growth of P. oryzae as the pathogen over grew the bio-agents.


2018 ◽  
Vol 30 (1) ◽  
pp. 75 ◽  
Author(s):  
Gul B. Poussio ◽  
Manzoor A. Abro ◽  
Jamal U. D. Hajano ◽  
Muhammad I. Khaskheli ◽  
Khalid I. Rajput ◽  
...  

Fusarium oxysporum f.sp. lycopersici (FOL) is a highly destructive fungal pathogen of tomato crop causing wilt disease which may reduce 10 to 90% yield. In Pakistan, tomato is widely grown in Sindh province, major territories are district Hyderabad, Tando Allahyar and Mirpurkhas. Thus, surveys of these territories were conducted to record intensity of the disease and confirm etiology. Furthermore, potential of different botanical pesticides and commercially available fungicides were tested to inhibit mycelial growth of the causal fungus. The experiment was laid down with complete randomized block design with three replications. The results showed that the disease was occurring in all locations with the range of 8-47 % incidence. F. oxysporum f.sp. lycopersici was predominantly isolated from the collected disease sample during survey and pathogenic nature of the fungus was tested on the tomato Golo variety through soil drenching method. The disease incidence of 30 and 42 % (72 % as total) was recorded in inoculated tomato plants at 20 and 40 DAI, respectively. Maximum (67 %) inhibition of the fungal growth was found by neem seed extracts at higher dose of 8 % concentration followed by 63 % with neem seeds and Eucalyptus at 6 and 8 %, respectively. Alternatively, the Nativo 75 WG fungicide was found most effective in reducing the redial mycelial growth of target fungus followed by Topsin-M at 1000 ppm where as Aliette and Melodedue fungicides were found least effective under in-vitro conditions.


2017 ◽  
Vol 9 (4) ◽  
pp. 2327-2331 ◽  
Author(s):  
Balkishan Chaudhary ◽  
Sanjeev Kumar ◽  
Shiva Kant Kushwaha

Three biocontrol agent viz., Trichoderma viride, Trichoderma virens and Trichoderma harzianum were evaluated to test the antagonism against Fusarium udum under in vitro conditions. All the three biocontrol agents have the potential of parasitizing the growth of Fusarium udum in vitro. The rate of parasitism was found fastest in T. viride (61.12% over growth in 96 hrs) than T. virens and T. harzianum. The volatile compounds from Trichoderma viride suppressed the mycelial growth of Fusarium udum by 43.13% and found effective when compared to Tricho-derma virens and Trichoderma harzianum. Non-volatile compounds or culture filtrate from Trichoderma virens at 15% concentration shows complete mycelial inhibition of the test fungi. The antagonist T. virens was chosen to be the most promising bio-control agent for F. udum.


2019 ◽  
Vol 17 (4) ◽  
pp. 446-453
Author(s):  
Victor Ohileobo DANIA

Tuber rot disease constitutes a serious threat to sweetpotato production worldwide, causing economic losses to farmers.  This study evaluated an eco-friendly approach using four biological control agents, Trichoderma viride, T. harzianum, T. hamatum and T. pseudokoningii for the management of post-harvest tuber rot disease of sweetpotato. Field surveys for infected tuber samples were conducted four across major sweetpotato states in Nigeria. Rot severity in inoculated tubers was evaluated over a storage period of four months and Trichoderma species isolated from the rhizosphere were bioassayed for the production of metabolites to evaluate the mechanism of antibiotic production for the control of rot pathogens using Gas Chromatography-Mass Spectroscopy. A total of 24 metabolites were produced by the Trichoderma species and the abundances were species dependent. Trichoderma species significantly (p<0.05) inhibited rot in treated tubers at 4 months after storage. However, T. harzianum was most effective, reducing mycelia growth of the rot pathogens by 54.6-77.3% in vitro and 47.2-68.8% reduction of rot incidence in vivo. The efficacy of Trichoderma species used in this study recommends their use as alternative therapy to synthetic fungicides in the management of post-harvest rot in sweetpotato. J Bangladesh Agril Univ 17(4): 446–453, 2019


2012 ◽  
Vol 48 (No. 3) ◽  
pp. 110-115 ◽  
Author(s):  
D. Alice ◽  
S. Sundravadana

Gloriosa superba is a medicinal plant severely infested with soil-borne Macrophomina phaseolina (Tassi) Goid. Under in vitro conditions a commercial formulation of Trichoderma viride and Pseudomonas fluorescens inhibited the mycelial growth of M. phaseolina isolates. Among the oil cake, mahua cake at 10% completely inhibited the mycelial growth of the M. phaseolina isolates. Under field conditions both the soil and foliar application of biocontrol agents is attributed to the healthy growth of G. superba crops by controlling the tuber rot disease and ultimately boosting the colchicine content.


2021 ◽  
Vol 50 (2) ◽  
pp. 423-425
Author(s):  
Ramesh Kumar ◽  
Sanjeev Kumar ◽  
Balkishan Chaudhary

Six biocontrol treatments viz., Trichoderma viride, Trichoderma virens, Trichoderma harzianum, T. harzianum + T. viride, T. harzianum + T. virens and T. viride + T. virens were evaluated to test the antagonism against Fusarium verticillioides under in vitro conditions. The maximum growth inhibition (90.6%) was recorded in consortium of T. harzianum + T. viride in dual culture technique . The volatile and non volatile compounds from the consortium of T. harzianum + T. viride also found best and suppressed the mycelial growth of F. verticillioides to the tune of 83.90 and 84.61 %, respectively. Bangladesh J. Bot. 50(2): 423-425, 2021 (June)


Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1254-1260 ◽  
Author(s):  
Erin Lonergan ◽  
Julie Pasche ◽  
Linnea Skoglund ◽  
Mary Burrows

Management of Ascochyta blight in pea, lentil, and chickpea relies on repeated fungicide applications, which has led to development of fungicide resistance and disease control failures in some systems. In vitro assays were conducted to determine baseline fungicide sensitivity in Mycosphaerella pinodes (Ascochyta pinodes), A. lentis, and A. rabiei populations to the demethylation-inhibiting fungicide prothioconazole and the succinate dehydrogenase-inhibiting fungicides boscalid and fluxapyroxad by determining the effective concentration at which 50% of germination or fungal growth was inhibited (EC50). Mean boscalid EC50 values from conidial germination assays were 0.669, 0.639, and 0.171 μg/ml and from mycelial growth assays were 0.258, 0.791, and 0.443 μg/ml for M. pinodes, A. lentis, and A. rabiei, respectively. Mean fluxapyroxad EC50 values were 0.050, 0.763, and 0.057 μg/ml for M. pinodes, A. lentis, and A. rabiei, respectively. Mean baseline EC50 values for prothioconazole with mycelial growth were 0.541, 0.604, and 0.283 μg/ml for M. pinodes, A. lentis, and A. rabiei, respectively. A single discriminatory fungicide concentration of 1 μg/ml was selected for all species. Established sensitivity profiles and discriminatory concentrations will be used to monitor sensitivity shifts in populations of Ascochyta spp. and to make effective disease management recommendations.


2017 ◽  
Vol 9 (4) ◽  
pp. 1916-1920
Author(s):  
Vipin Kumar ◽  
V.P. Chaudhary ◽  
Dharmendra Kumar ◽  
Ajay Kumar ◽  
Sushma Sagar ◽  
...  

Among the fungal diseases, sheath blight, caused by multinucleate Rhizoctoniasolani Kuhn (teleomorph: Thanatephorus cucumeris Donk), a ubiquitous pathogen, is an important fungal disease of rice ranking only after blast and often rivalling it. The potential losses due to sheath blight alone in India has been up to 51.3%. In this study an attempt was made to investigate the antifungal efficacy of botanicals viz., neem (Azadirachtaindica), tulsi (Ocimum sanctum), garlic (Allium sativum), onion (Allium cepa), ginger (Zingiberofficinale) and various fungicides namely mancozeb, propiconazole, hexaconazole, carbendazim, and copper oxychlorideagainst Rhizoctoniasolani in vitro by poison food technique. R. solani was allowed to grow at 5%, 10% concentrations of botanicals and at 200, 500, 1000ppm of fungicides amended potato dextrose agar (PDA) medium. The effect of botanicals and fungicides on mycelial growth inhibition was recorded after 36, 48 and 72 post hrs inoculation (phi). It was observed that bulb extract of Allium sativum and rhizome extract of Zingier officinal suppressed the mycelial growth (80.19 and 76.32, respectively) @ 10% followed by leaf extract of Azadirachtaindica (72.78 %) after 72 phi. Among the fungicides, the complete fungal growth inhibition was observed in propiconazole and carbendazim fungicides amended medium.


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