Papers by Anderson Amadioha
Journal of Herbs, Spices & Medicinal Plants, 1998
Cold and hot water leaf extracts of papaya (melon tree, pawpaw) (Carica papaya L.) were effective... more Cold and hot water leaf extracts of papaya (melon tree, pawpaw) (Carica papaya L.) were effective in reducing the growth of powdery mildew fungi in vitro and in reducing the spread of powdery mildew disease on pepper plants. The toxicity of cold water leaf extracts of papaya to fungi was greater than that of hot water extracts, suggesting the bioactive extract could be heat sensitive. Leaf extracts of papaya have the potential for control of powdery mildew disease of pepper in the field.
International Journal of Pest Management, 1996
ABSTRACT Solutions of six fungicides, Benlate, Dithane M 45, Captan, Cupravit, Brestan and Borax,... more ABSTRACT Solutions of six fungicides, Benlate, Dithane M 45, Captan, Cupravit, Brestan and Borax, were tested for control of soft rot in potato caused by Rhizopus oryzae. Low temperatures in isolation or in combination with the fungicides as well as storage In open laboratory, farm barn, and well drained soil pits were also separately evaluated against natural infections of the tubers by the fungus. Captan, benlate and cupravit at 400–500 ppm were consistently effective against spore germination, mycelial growth and rot development by the rot‐causing organism. Low temperatures (0–5°C) completely inhibited the spore germination and rot development by the pathogen. A low temperature‐captan or benlate combination involving the dipping of harvested potato tubers in 300 ppm captan or benlate and storing at 10°C proved very effective against the rot incited by the pathogen. Storage of potato in well drained soil pits particularly in open sites significantly reduced natural infection of the tubers by the fungus.
Asian Journal of Agriculture
Enyiukwu DN, Amadioha AC, Ononuju CC. 2021. Evaluation of some pesticides of plant origin for con... more Enyiukwu DN, Amadioha AC, Ononuju CC. 2021. Evaluation of some pesticides of plant origin for control of anthracnose disease (Colletotrichum destructivum O'Gara) in cowpea. Asian J Agric 4: 4-11. Anthracnose is a common disease of cowpea in many bean growing areas of the world. This study evaluated the effects of Alchornea cordifolia, Tabernaemontana pachysiphon, and Lantana camara as low-input biopesticides for control of the disease. The experiment was laid out in randomized complete block design (RCBD) made up of 14 treatments with 4 replications. The results indicated that all the plant materials irrespective of carrier solvent and concentrations of application significantly (P≤0.05) minimized the incidence and severity of the disease as well as improved the yield and yield parameters of the treated crop than the control. Amongst all evaluated dosages of the plant materials, 50-100 % concentration of L. camara gave the best disease control and yield improvement of the crop, followed by full strength of T. pachysiphon and A. cordifolia was the least. However, comparative to benomyl a standard fungicide, the plant-derived pesticides demonstrated lower fungitoxicity against the pathogen with the exception of 50-100 % extracts of L. camara which were statistically (P≥0.05) at par with the effects of the fungicide. Therefore all the plant extracts could be used at higher doses as prophylactics to stem the disease; however, L. camara could be applied at lower doses to achieve the same level of control. These plant materials in the overall could therefore contribute as effective bio-fungicides towards improving productivity of cowpea in the humid tropics.
Nusantara Bioscience, 2020
Abstract. Enyiukwu DN, Amadioha AC, Ononuju CC. 2021. Histological aberrations and mode of damage... more Abstract. Enyiukwu DN, Amadioha AC, Ononuju CC. 2021. Histological aberrations and mode of damage of cowpea (Vigna unguiculata) by Colletotrichum destructivum. Nusantara Bioscience 13: 16-23. Leaf and stem of healthy 2-week old cowpea (Vigna unguiculata L. Walp.) seedlings were inoculated with spore suspension of the Colletotrichum destructivum O’Gara. Sections of the infection courts were prepared and examined under digital microscope. The results showed that the infection process began 12 hours after inoculation (hai) with the germination of spores of the fungus. Large multi-lobed primary hypha (somewhat spherical in shape) developed from the infection peg and remained inside a single epithelial cell for about 3 days. Towards the end of this time, the primary hyphae developed thin filamentous tentacles that punctured and branched into adjoining cells, initiating necrotrophic phase of the disease. During this period, typical anthracnose symptoms began to develop on the infected org...
Asian Journal of Natural Product Biochemistry, 2021
Cowpea is an important grain and leafy vegetable in many tropical locations. Anthracnose caused b... more Cowpea is an important grain and leafy vegetable in many tropical locations. Anthracnose caused by Colletotrichum destructivum O'Gara is one of the several factors constraining the economic production of the crop in warm humid areas. Use of resistant varieties and synthetic pesticides for control of the disease in the crop are disadvantaged for variability of the pathogen, leading to resistance failure of cultivars in many cowpea growing areas; and pesticide residues in the treated crops which ultimately engender mammalian toxicity respectively. This study evaluated the effects of Alchornea cordifolia, Tabernaemontana pachysiphon and Lantana camara as eco-friendly fungicides against the pathogen in culture. The results showed that the extracts inhibited the fungus in a dose-wise manner. At 75 and100 % concentrations, L. camara strongly inhibited the spore germination and radial growth of the fungus better than all concentrations of T. pachysiphon and A. cordifolia; whereas A. cordifolia extracts exhibited the lowest inhibition at all concentrations. Generally, the fungitoxicity of benomyl was found higher which inhibited 90.15 % spore germination and 96.32 % radial growth of the pathogen. However, at 75%, 100% L. camara and 100% T. pachysiphon which significantly (P≤0.05) inhibited (80.02%, 84.21 % and 80.91%) spore germination and (87.33%, 90.87 % and 85. %) radial growth of the fungus respectively compared well with inhibition effects recorded from benomyl. Therefore these plants can be used as viable protectants of cowpea against anthracnose (C. destructivum) in small holder farming systems of the humid tropics; to enhance its production and farm economy.
Acta Phytopathologica et Entomologica Hungarica
Hot and cold water leaf extracts of Cymbopogon citratus and Ocimum gratissimum were effective in ... more Hot and cold water leaf extracts of Cymbopogon citratus and Ocimum gratissimum were effective in reducing the spore germination and radial growth of Colletotrichum lindemuthianum in vitro and the growth of the pathogen in vivo .Cold water tissue extract of C.citratus was the best in reducing the growth of the pathogen in vitro and in checking the spread of anthracnose disease of cowpea in vivo.C. citratus could be used as source of a pesticide of plant origin to control the pathogen of cowpea in the field.
Investigations on the anatomical aberrations and biochemical alterations of white yam incited by ... more Investigations on the anatomical aberrations and biochemical alterations of white yam incited by Botryodiplodia theobromae was carried out. Inoculated and uninoculated head, middle and tail portions of white yam were treated, sectioned weekly for five weeks and photomicrographs taken. The plates revealed massive cell wall macerations and depletion of starch grains in the three portions of yam assessed. Less damage was evident in the head portion especially after one week of infection compared with the middle and tail portions. However, there was general progressive tissue destruction and starch grains depletion with weeks. Inoculated and uninoculated yam samples were also analyzed for the carbohydrate content weekly for five weeks. Results showed that there was a reduction for carbohydrate with increase in weeks of infection. Values of 24.60 mg, 25.1 mg and 23.9 mg carbohydrate per 100 g of edible portion of white yam were recorded after one week of infection for the head, middle an...
Tubers of white yam (Dioscorea rotundata Poir) obtained in three markets in Calabar, Cross River ... more Tubers of white yam (Dioscorea rotundata Poir) obtained in three markets in Calabar, Cross River State, Nigeria, were found associated with seven microbial pathogens causing dry and wet rot of tissues. The pathogens included; Aspergillus niger, Penicillium expansum, Fusarium oxysporum, Botryodiplodia theobromae, Penicillium sclerotigenum, Fusarium moniliformes, and Rhizopus stolonifer. Of these A. niger, P. expansum, F. oxysporium and B. theobromae were highly pathogenic causing extensive tissue rot compared to the last three. Botryodiplodia theobromae effected an appreciable reduction in the amounts of nutrients in the head, middle and tail portions of yam tested within the five-week span of the experiment. One week after inoculation, there was a decline in the carbohydrate content from 34.80mg/100g dry weight in the control samples to 24.60mg, 25.10mg and 23.90mg in the head, middle and tail portions respectively. These values fell to 16.90 and 16.80mg/100g by the fifth week in th...
The carbohydrate fractions, protein and lipid contents of two cultivars of potato namely, Irish C... more The carbohydrate fractions, protein and lipid contents of two cultivars of potato namely, Irish Cobbler and Red Pontiac, were altered quantitatively by Rhizopus oryzae during the 10-day incubation period. Glucose content increased during the incubation period for both healthy and inoculated tubers. Starch, maltose, sucrose, protein and lipid contents decreased more rapidly in inoculated tubers than in healthy tubers in both cultivars. The depletion in starch and protein in the infected tubers appeared to be greater for Irish Cobbler than in Red Pontiac; decreases for other constituents seemed fairly comparable.
World Journal of Microbiology & Biotechnology, 1993
Rhizoctonia bataticola produced oxalic acid in vitro and in vivo during pathogenesis of patato tu... more Rhizoctonia bataticola produced oxalic acid in vitro and in vivo during pathogenesis of patato tuber. Polygalacturonase (PG) was also detected in culture filtrates of the rot-causing organism. Levels of maceration and cell death in tuber tissue were higher when a mixture of oxalic acid and PG was used than when either oxalic acid or PG were used alone.
Food / Nahrung, 1994
ABSTRACT No abstract is available for this article.
Journal of Herbs, Spices & Medicinal Plants, 1998
ABSTRACT Hot water and oil extracts of Azadirachta indica (neem) and Xylopia aethiopica significa... more ABSTRACT Hot water and oil extracts of Azadirachta indica (neem) and Xylopia aethiopica significantly reduced spore germination and growth of Colletotrichum lindemuthianum in vitro. Tests with cowpea (Vigna unguiculata) indicated the extracts applied before or after infection of the plants with Colletotrichum lindemuthianum were also effective in reducing the size of pathogen induced lesions. The fungitoxicity of the extracts from Azadirachta indica and Xylopia aethiopica was greater than that of bonomyl.
Archives Of Phytopathology And Plant Protection, 2007
ABSTRACT Investigations were carried out on the pesticidal potentials of seed of Piper nigrum and... more ABSTRACT Investigations were carried out on the pesticidal potentials of seed of Piper nigrum and Aframomum melegueta and leaves of P. nigrum and Ageratum conyzoides using water, ethanol and petroleum ether as extracting solvents. Leaf extracts of P. nigrum and A. conyzoides and seed extracts of A. melegueta and P. nigrum significantly inhibited the mycelial radial growth and mycelial biomass of Botryodiplodia acerina in vitro. Ethanol extracts recorded the highest growth inhibition followed by water and petroleum ether extracts. The extracts checked the rot development in unwounded cassava tubers especially when they were applied before spray-inoculating with B. acerina. Water leaf extracts of P. nigrum and A. conyzoides and seed extracts of A. melegueta and P. nigrum could be a potent source of natural pesticide for managing post-harvest rot of cassava tubers caused by B. acerina.
Archives Of Phytopathology And Plant Protection, 2002
Aims: Brown spot disease is among the important crop diseases of rice caused by the infection of ... more Aims: Brown spot disease is among the important crop diseases of rice caused by the infection of a pathogenic fungus, Cochliobolus miyabeanus that results in yield losses. Nowadays, limited studies on volatile organic compounds (VOCs) have been carried out using pathogenic fungal isolate. Hence, this study was conducted to identify VOCs produced by C. miyabeanus wild-type isolate, WK1C, a causal agent of brown spot disease using gas chromatography-mass spectrometry (GC-MS). Methodology and results: Fungal isolate WK1C was cultured on potato dextrose agar (PDA) and in potato dextrose broth (PDB) for extraction. The extracts were analysed using GC-MS and the profiles of VOCs were obtained. Cochliobolus miyabeanus WK1C isolate showed a significant presence of various types of organic compound including ester, alcohol, phenol, alkane, alkene, ketone, carboxylic acid, amide and aldehyde. Conclusion, significance and impact of Study: This study important for a preliminary assessment of VOCs profiles of C. miyabeanus, a causal agent of brown spot disease. In order to identify the compounds contribute to pathogenicity, further study can be conducted to identify the virulence factor of brown spot disease using different approaches.
Archives Of Phytopathology And Plant Protection, 2001
Extracts of Cymbopogon citratus, Azadirachta indica (Neem) and Ocimum gratissimum were effective ... more Extracts of Cymbopogon citratus, Azadirachta indica (Neem) and Ocimum gratissimum were effective in controlling the growth of Rhizopus oryzae in vitro and in vivo. Neem was found to be the best followed by C. citratus and O. gratissimum. Alcohol extracts of these plant species were more effective than water extracts in reducing the growth of the pathogen in culture and in checking rot development in potato tuber by the fungus. A. indica and C. citratus have considerable disease control potential and their extracts can be exploited as a source of pesticide of plant origin to control the soft rot in stored potato incited by Rhizopus oryzae.
Archives Of Phytopathology And Plant Protection, 2001
ABSTRACT The leaf extracts of Piper guinensis, Ocimum sanctum, O. gratissimum and Cymbopogon citr... more ABSTRACT The leaf extracts of Piper guinensis, Ocimum sanctum, O. gratissimum and Cymbopogon citratus were effective in reducing the radial growth of Rhizoctonia solani in vitro and in checking the spread of the disease caused by the pathogen in the field. P. guinensis was the best in checking the spread of the pathogen both in vitro and in vivo. This was followed by C. citratus, O. sanctum and O. gratissimum. Citrus limon reduced the radial growth of the pathogen in vitro but failed to check the spread of the disease effectively in the field. Alcohol extracts were more effective than water extracts.
Archives Of Phytopathology And Plant Protection, 2000
ABSTRACT Rhizoctonia bataticola produced the highest amounts of amylase in medium containing star... more ABSTRACT Rhizoctonia bataticola produced the highest amounts of amylase in medium containing starch than that lacking starch within the 10 days of culture. Doubling the concentration of starch in the growth medium resulted in a near doubling of the amylase activity. Amylase production by the fungus is related to the type of carbon source in the medium with maximum amylase produced in medium containing starch. The maximum activity of the enzyme was detected in extracellular filtrates obtained from 4 days cultures. After this period, amylase activity decreased at first, and then increased through the 10 days incubation period. The fungus produced maximum levels of amylase prior to attainment of maximum mycelial biomass. Peak activity of the extracellular amylase was recorded at a temperature and pH range of 20–25°C and 4–5 respectively. The role of the exoenzyme in the deterioration of stored food products and its possible use in industrial fermentation processes are discussed.
Archives Of Phytopathology And Plant Protection, 2007
Polygalacturonase (PG) activity was detected in culture filtrate and Rhizoctonia-infected tissues... more Polygalacturonase (PG) activity was detected in culture filtrate and Rhizoctonia-infected tissues of potato tubers (Solanum tuberosum L.). Culture-produced PG formed more reducing groups than PG from diseased tissue. PG production and pH of the culture medium increased with the incubation period and attained optimal values between the 4th and 6th days. The ability of R. bataticola to produce PG varied
Archives Of Phytopathology And Plant Protection, 1998
ABSTRACT Cold storage and application of six fungicides ‐ Captan, Cupravit, Benlate, Dithane M45,... more ABSTRACT Cold storage and application of six fungicides ‐ Captan, Cupravit, Benlate, Dithane M45, Brestan and Borax as well as storage in open laboratory, farm bans and soil pits were separately evaluated against Rhizoctonia bataticola causing black rots of potato (Solanum tuberosum L.). Also tried against artificial or natural infections of potato in the laboratory was low temperature in combination with either Captan or Benlate.The mycelial growth and rot development by the pathogen were completely inhibited by low temperature (0–10°C) and two of the fungicides, Captan and Benlate at 250–500 ppm. A low temperature‐Captan or low temperature‐Benlate combination involving the dipping of potato in 300 ppm Captan or 400 ppm Benlate and storing at 15°C as well as storage in well drained soil pits particularly in open sites proved very effective against the potato tuber rot cause by Rhizoctonia bataticola.
Uploads
Papers by Anderson Amadioha