Elizabeth Ngadze - Academia.edu (original) (raw)
Papers by Elizabeth Ngadze
Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent b... more Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent but can become an environmental problem if its growth is not controlled. Water hyacinth is a potential raw material of several industrial applications. However chemical structure of the lignocellulosic hyacinth biomass has to be broken down first in order to obtain fermentable sugars. Wood rotting fungi has been known to delignify plant biomass. Wood rotting fungi secrete extracellular enzymes including lignin peroxidase, manganese peroxidase and laccase that are important industrial enzymes with numerous biotechnological applications in bio-fuel, food, brewery and wine, animal feed, textile and laundry, pulp and paper and agricultural industries. This paper reviews the potential use of white rot fungi's ( Pleurotus sajor caju, Pleurotus ostreatus and Lentinus edodes ) extracellular enzymes to biodegrade water hyacinth biomass. Keywords: water hyacinth, lignocelluloses, wood rotting ...
African Crop Science Journal, 2020
The use of living organisms or natural enemies of pathogens to control their populations is calle... more The use of living organisms or natural enemies of pathogens to control their populations is called biological disease control. It involves harnessing and introduction of exotic species of microorganism in a natural form, with the intention of controlling pathogens that may exist naturally in the same ecosystem. Prospects for biological control of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum were investigated using Streptomyces spp. isolated from Chinhoyi University of Technology Farm soils in Mashonaland West, Zimbabwe. Twenty seven Streptomyces spp were obtained from the soil, and screened for antimicrobial activity and antagonism in in vitro pathogen inhibition assays, replicated thrice. Although majority of the isolates tested elicited no effect on test pathogens, 22% of the Streptomyces isolates were able to effectively suppress A. flavus, F. oxysporum and P. italicum by at least 55%. There was a significant interaction between Streptomyces isolates and pathog...
Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent b... more Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent but can become an environmental problem if its growth is not controlled. Water hyacinth is a potential raw material of several industrial applications. However chemical structure of the lignocellulosic hyacinth biomass has to be broken down first in order to obtain fermentable sugars. Wood rotting fungi has been known to delignify plant biomass. Wood rotting fungi secrete extracellular enzymes including lignin peroxidase, manganese peroxidase and laccase that are important industrial enzymes with numerous biotechnological applications in bio-fuel, food, brewery and wine, animal feed, textile and laundry, pulp and paper and agricultural industries. This paper reviews the potential use of white rot fungi's ( Pleurotus sajor caju, Pleurotus ostreatus and Lentinus edodes ) extracellular enzymes to biodegrade water hyacinth biomass. Keywords: water hyacinth, lignocelluloses, wood rotting ...
African Crop Science Journal, 2020
The use of living organisms or natural enemies of pathogens to control their populations is calle... more The use of living organisms or natural enemies of pathogens to control their populations is called biological disease control. It involves harnessing and introduction of exotic species of microorganism in a natural form, with the intention of controlling pathogens that may exist naturally in the same ecosystem. Prospects for biological control of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum were investigated using Streptomyces spp. isolated from Chinhoyi University of Technology Farm soils in Mashonaland West, Zimbabwe. Twenty seven Streptomyces spp were obtained from the soil, and screened for antimicrobial activity and antagonism in in vitro pathogen inhibition assays, replicated thrice. Although majority of the isolates tested elicited no effect on test pathogens, 22% of the Streptomyces isolates were able to effectively suppress A. flavus, F. oxysporum and P. italicum by at least 55%. There was a significant interaction between Streptomyces isolates and pathog...
International Journal of Agronomy, 2021
Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solan... more Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solanum esculentum L. (tomato); as a result, it makes the pathogen one of the most devastating plant diseases across the world. The control of late blight is difficult because P. infestans has advanced and complex enzymes and effecter molecules coded by avirulence genes. As such, a study was carried out at the University of Zimbabwe, Department of Plant Production Sciences and Technologies, between August 2018 and May 2019 to evaluate the efficacy of Moringa oleifera Lour. (moringa), Eucalyptus nigra R.T. Baker (gumtree), and Lantana camara L. (sensu lato) (lantana) extracts as biofungicides on late blight development on S. esculentum. The effect of acetone, ethyl acetate, and water extracts of M. oleifera, E. nigra, and L. camara on percent inhibition and radial growth were evaluated in the laboratory. In addition, the efficacy of different extract concentrations of M. oleifera, E. nigra, an...
African Journal of Food, Agriculture, Nutrition and Development, 2016
In Zimbabwe, the average sweet potato yield (6 t/ha) is relatively low when compared to Asian cou... more In Zimbabwe, the average sweet potato yield (6 t/ha) is relatively low when compared to Asian counterparts (17 t/ha). These low crop yields have been blamed on weevil infestations and viral infections which account for 60-90% of sweet potato yield losses in Africa. Meristem tip culture, a Centre for Potato Improvement (CIP) initiated tissue culture technique, has been widely used to eradicate viruses from clonally propagated crops and has been noted to be one of the instrumental techniques that helped China to increase sweet potato yields. In an effort to adopt the meristem tip culture technique for the production of virus-free planting material of a local sweet potato (cv Brondal), a study was conducted to evaluate the effect of Benzylamino purine (BAP), 1-Naphthaleneacetic acid (NAA) and Gibberellic acid (GA3) (either alone or in combination) on cultured Brondal meristems. The different hormonal treatments were assessed on the following parameters: plantlet regenerative capacity, ...
Journal of Plant Sciences, 2016
Aphids cause loss of quality and value in butternut crops due to pest injury and the transmission... more Aphids cause loss of quality and value in butternut crops due to pest injury and the transmission of viruses in a non-persistent manner. A field experiment was conducted in Daylesford, Gweru in August 2012/2013 planting season to evaluate border cropping practice as a management strategy for aphid infestation and damage in butternut squash (Cucurbita moschata). The experiment was arranged as a 2 x 2 + 1 factorial in a randomised complete block design (RCBD) replicated 4 times. Treatments were Maize (Zea mays) border planted at 25 000 and 45 000 plants/ha and sorghum (Sorghum bicolor) border planted at 200 000 and 260 000 plants/ha plus a butternut crop with no border (control). All borders were planted 0.5 m from the butternut crop. Data on aphid counts on borders and on butternuts, disease incidence, yield and land equivalent ratio for the intercrops was recorded. Results showed that, border crops and border density interacted significantly (p < 0.05) to to reduce aphid populati...
African Crop Science Journal, May 31, 2018
In Zimbabwe, yield of oyster mushroom (Pleurotus ostreatus) grown on sole substrates of maize or ... more In Zimbabwe, yield of oyster mushroom (Pleurotus ostreatus) grown on sole substrates of maize or sorghum straw is low, <75% biological efficiency translating to less than a kilogramme of fresh mushroom per kg of dry substrate. This study aimed at determining the effect of mixing sorghum or maize straw with various proportions of bean straw, on the yield of grey oyster mushroom. Maize and sorghum straws were singly mixed with 0, 20, 40, 60, 80 and 100% bean straw, followed by a spawning rate of 5%. Eighteen days after incubation in a dark room, bags were hanged in a mushroom growing house with controlled temperatures (25-26 o C). Mixing bean with maize straw had a significantly higher oyster mushroom yield (1, 229 g) than with sorghum straw (1,138 g); leading to biological efficiency of 83 and 74%, for maize straw and sorghum straw, respectively. Yield and biological efficiency decreased from 1,357 to 977 g plot-1 and 97 to 61%, respectively, when the proportion of bean straw was increased from 0-100%; while number of days to second and third harvest increased. There were significant interactions (P<0.05) for the number of pins, days to second and third harvest, between maize or sorghum straw with bean straw. Maize straw gave better performance with high percentages of bean straw than sorghum straw. Results showed that maize straw mixed with 20% bean straw produced better yield of grey oyster mushroom.
Advances in Agriculture, 2020
Livingstone potato (Plectranthus esculentus N.E.Br) is an underutilised indigenous root vegetable... more Livingstone potato (Plectranthus esculentus N.E.Br) is an underutilised indigenous root vegetable grown by communal farmers in the eastern provinces of Zimbabwe. It is vegetatively propagated using unimproved retained tubers from the previous season. The risk of disease carryover is therefore high, leading to poor yields. The objective of the study was to exploit the tissue culture technique of micropropagation to produce a mass supply of healthy planting material for improved productivity. Two experiments were conducted: firstly, to determine the best explant type and secondly, to determine the best landrace and plant growth regulators for the growth of plantlets. The landraces, namely, Ndurwe, Musande, Chibanda, and Chizambezi, were sourced from communal farmers in the stated production areas. Naphthalene acetic acid (NAA) and benzyl amino purine (BAP) were the auxin and cytokinin used, respectively. The first experiment was laid out as a randomized complete block design (RCBD) wi...
Seed Science and Technology, 2019
Hyphaene petersiana is a naturally occurring palm tree in Zimbabwe. The tree provides an importan... more Hyphaene petersiana is a naturally occurring palm tree in Zimbabwe. The tree provides an important supplementary source of income to the communities where it is found, with a high demand for foliage for making baskets and sap for wine making. Propagation is both by vegetative and sexual methods, however, sexual propagation is constrained by the inherent dormancy of the seeds. Breaking seed dormancy is also the first step towards developing a conservation programme for the tree. The effect of water soaking (for 12, 24 and 48 hours), chemical scarification (sulphuric acid for 10 minutes), de-husking (tegument removal), sand papering as well as chemical treatment (thiourea and potassium nitrate) were compared with untreated seeds (control). No germination was observed for seeds treated with sulphuric acid. Water soaking for 12 hours gave the highest germination (71.7%) although not significantly different to other treatments.
African Journal of Agricultural Research, 2018
African Crop Science Journal, 2019
African journal of agricultural research
Contamination of potato with soft rotting enterobacteria belonging to the Pectobacterium and dick... more Contamination of potato with soft rotting enterobacteria belonging to the Pectobacterium and dickeya geners is one of the biggest problems in potato production. Calcium plays an important role in minimising the severity and incidence of potato tuber soft rot in storage. This review gives a detailed assessment of the epidemiology of the pathogens and how calcium affects potato tuber soft rot in storage.
European Journal of Plant Pathology, 2012
Potato production globally is constrained by factors which cause substantial economic losses. The... more Potato production globally is constrained by factors which cause substantial economic losses. These can be in the form of biotic and abiotic factors. The greatest losses are due to diseases and some of the important bacterial diseases are tuber soft rot, blackleg and aerial stem rot in the field. Tuber soft rot also causes high economic losses in transit and in storage. These diseases are caused by Pectobacterium and Dickeya spp. These pectolytic bacteria have various overwintering sites such as plant debris, water and pupae of several insect species. The pathogens enter plant tissues through wounds, lenticels and stolon ends where they remain latent, or cause symptoms if conditions are conducive for disease development. In latent infections, the bacteria remain dormant until climatic conditions are favourable for symptom development. The pathogens secrete different isoforms of extracellular enzymes which can break down living and dead plant tissues. Conditions which favour disease ...
IOSR Journal of Agriculture and Veterinary Science, 2014
A survey to assess the distribution and impact of the potato blackleg/soft rot disease complex in... more A survey to assess the distribution and impact of the potato blackleg/soft rot disease complex in Zimbabwe was conducted from September 2009 to June 2010. Sixty-four questionnaires were collected from 9 potato growing areas in Zimbabwe. The farmers are aware of the existence of soft rot post-harvest decay, seed piece decay and blackleg disease. The most predominant management method for the (three) 3 diseases was the use of rotation cycles with various crops. Estimates of economic losses caused by the diseases ranged from <1 to 65% with the average being approximately 23%. The most popular cultivars grown in Zimbabwe are Amethyst and BP1, which were ranked as susceptible by more than 50% of the growers. The disease symptoms are more prevalent at temperatures between 15-20 ˚C with moist or humid conditions.
Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent b... more Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent but can become an environmental problem if its growth is not controlled. Water hyacinth is a potential raw material of several industrial applications. However chemical structure of the lignocellulosic hyacinth biomass has to be broken down first in order to obtain fermentable sugars. Wood rotting fungi has been known to delignify plant biomass. Wood rotting fungi secrete extracellular enzymes including lignin peroxidase, manganese peroxidase and laccase that are important industrial enzymes with numerous biotechnological applications in bio-fuel, food, brewery and wine, animal feed, textile and laundry, pulp and paper and agricultural industries. This paper reviews the potential use of white rot fungi's ( Pleurotus sajor caju, Pleurotus ostreatus and Lentinus edodes ) extracellular enzymes to biodegrade water hyacinth biomass. Keywords: water hyacinth, lignocelluloses, wood rotting ...
African Crop Science Journal, 2020
The use of living organisms or natural enemies of pathogens to control their populations is calle... more The use of living organisms or natural enemies of pathogens to control their populations is called biological disease control. It involves harnessing and introduction of exotic species of microorganism in a natural form, with the intention of controlling pathogens that may exist naturally in the same ecosystem. Prospects for biological control of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum were investigated using Streptomyces spp. isolated from Chinhoyi University of Technology Farm soils in Mashonaland West, Zimbabwe. Twenty seven Streptomyces spp were obtained from the soil, and screened for antimicrobial activity and antagonism in in vitro pathogen inhibition assays, replicated thrice. Although majority of the isolates tested elicited no effect on test pathogens, 22% of the Streptomyces isolates were able to effectively suppress A. flavus, F. oxysporum and P. italicum by at least 55%. There was a significant interaction between Streptomyces isolates and pathog...
Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent b... more Water hyacinth is a useful weed in the cleaning of water bodies loaded with industrial effluent but can become an environmental problem if its growth is not controlled. Water hyacinth is a potential raw material of several industrial applications. However chemical structure of the lignocellulosic hyacinth biomass has to be broken down first in order to obtain fermentable sugars. Wood rotting fungi has been known to delignify plant biomass. Wood rotting fungi secrete extracellular enzymes including lignin peroxidase, manganese peroxidase and laccase that are important industrial enzymes with numerous biotechnological applications in bio-fuel, food, brewery and wine, animal feed, textile and laundry, pulp and paper and agricultural industries. This paper reviews the potential use of white rot fungi's ( Pleurotus sajor caju, Pleurotus ostreatus and Lentinus edodes ) extracellular enzymes to biodegrade water hyacinth biomass. Keywords: water hyacinth, lignocelluloses, wood rotting ...
African Crop Science Journal, 2020
The use of living organisms or natural enemies of pathogens to control their populations is calle... more The use of living organisms or natural enemies of pathogens to control their populations is called biological disease control. It involves harnessing and introduction of exotic species of microorganism in a natural form, with the intention of controlling pathogens that may exist naturally in the same ecosystem. Prospects for biological control of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum were investigated using Streptomyces spp. isolated from Chinhoyi University of Technology Farm soils in Mashonaland West, Zimbabwe. Twenty seven Streptomyces spp were obtained from the soil, and screened for antimicrobial activity and antagonism in in vitro pathogen inhibition assays, replicated thrice. Although majority of the isolates tested elicited no effect on test pathogens, 22% of the Streptomyces isolates were able to effectively suppress A. flavus, F. oxysporum and P. italicum by at least 55%. There was a significant interaction between Streptomyces isolates and pathog...
International Journal of Agronomy, 2021
Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solan... more Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solanum esculentum L. (tomato); as a result, it makes the pathogen one of the most devastating plant diseases across the world. The control of late blight is difficult because P. infestans has advanced and complex enzymes and effecter molecules coded by avirulence genes. As such, a study was carried out at the University of Zimbabwe, Department of Plant Production Sciences and Technologies, between August 2018 and May 2019 to evaluate the efficacy of Moringa oleifera Lour. (moringa), Eucalyptus nigra R.T. Baker (gumtree), and Lantana camara L. (sensu lato) (lantana) extracts as biofungicides on late blight development on S. esculentum. The effect of acetone, ethyl acetate, and water extracts of M. oleifera, E. nigra, and L. camara on percent inhibition and radial growth were evaluated in the laboratory. In addition, the efficacy of different extract concentrations of M. oleifera, E. nigra, an...
African Journal of Food, Agriculture, Nutrition and Development, 2016
In Zimbabwe, the average sweet potato yield (6 t/ha) is relatively low when compared to Asian cou... more In Zimbabwe, the average sweet potato yield (6 t/ha) is relatively low when compared to Asian counterparts (17 t/ha). These low crop yields have been blamed on weevil infestations and viral infections which account for 60-90% of sweet potato yield losses in Africa. Meristem tip culture, a Centre for Potato Improvement (CIP) initiated tissue culture technique, has been widely used to eradicate viruses from clonally propagated crops and has been noted to be one of the instrumental techniques that helped China to increase sweet potato yields. In an effort to adopt the meristem tip culture technique for the production of virus-free planting material of a local sweet potato (cv Brondal), a study was conducted to evaluate the effect of Benzylamino purine (BAP), 1-Naphthaleneacetic acid (NAA) and Gibberellic acid (GA3) (either alone or in combination) on cultured Brondal meristems. The different hormonal treatments were assessed on the following parameters: plantlet regenerative capacity, ...
Journal of Plant Sciences, 2016
Aphids cause loss of quality and value in butternut crops due to pest injury and the transmission... more Aphids cause loss of quality and value in butternut crops due to pest injury and the transmission of viruses in a non-persistent manner. A field experiment was conducted in Daylesford, Gweru in August 2012/2013 planting season to evaluate border cropping practice as a management strategy for aphid infestation and damage in butternut squash (Cucurbita moschata). The experiment was arranged as a 2 x 2 + 1 factorial in a randomised complete block design (RCBD) replicated 4 times. Treatments were Maize (Zea mays) border planted at 25 000 and 45 000 plants/ha and sorghum (Sorghum bicolor) border planted at 200 000 and 260 000 plants/ha plus a butternut crop with no border (control). All borders were planted 0.5 m from the butternut crop. Data on aphid counts on borders and on butternuts, disease incidence, yield and land equivalent ratio for the intercrops was recorded. Results showed that, border crops and border density interacted significantly (p < 0.05) to to reduce aphid populati...
African Crop Science Journal, May 31, 2018
In Zimbabwe, yield of oyster mushroom (Pleurotus ostreatus) grown on sole substrates of maize or ... more In Zimbabwe, yield of oyster mushroom (Pleurotus ostreatus) grown on sole substrates of maize or sorghum straw is low, <75% biological efficiency translating to less than a kilogramme of fresh mushroom per kg of dry substrate. This study aimed at determining the effect of mixing sorghum or maize straw with various proportions of bean straw, on the yield of grey oyster mushroom. Maize and sorghum straws were singly mixed with 0, 20, 40, 60, 80 and 100% bean straw, followed by a spawning rate of 5%. Eighteen days after incubation in a dark room, bags were hanged in a mushroom growing house with controlled temperatures (25-26 o C). Mixing bean with maize straw had a significantly higher oyster mushroom yield (1, 229 g) than with sorghum straw (1,138 g); leading to biological efficiency of 83 and 74%, for maize straw and sorghum straw, respectively. Yield and biological efficiency decreased from 1,357 to 977 g plot-1 and 97 to 61%, respectively, when the proportion of bean straw was increased from 0-100%; while number of days to second and third harvest increased. There were significant interactions (P<0.05) for the number of pins, days to second and third harvest, between maize or sorghum straw with bean straw. Maize straw gave better performance with high percentages of bean straw than sorghum straw. Results showed that maize straw mixed with 20% bean straw produced better yield of grey oyster mushroom.
Advances in Agriculture, 2020
Livingstone potato (Plectranthus esculentus N.E.Br) is an underutilised indigenous root vegetable... more Livingstone potato (Plectranthus esculentus N.E.Br) is an underutilised indigenous root vegetable grown by communal farmers in the eastern provinces of Zimbabwe. It is vegetatively propagated using unimproved retained tubers from the previous season. The risk of disease carryover is therefore high, leading to poor yields. The objective of the study was to exploit the tissue culture technique of micropropagation to produce a mass supply of healthy planting material for improved productivity. Two experiments were conducted: firstly, to determine the best explant type and secondly, to determine the best landrace and plant growth regulators for the growth of plantlets. The landraces, namely, Ndurwe, Musande, Chibanda, and Chizambezi, were sourced from communal farmers in the stated production areas. Naphthalene acetic acid (NAA) and benzyl amino purine (BAP) were the auxin and cytokinin used, respectively. The first experiment was laid out as a randomized complete block design (RCBD) wi...
Seed Science and Technology, 2019
Hyphaene petersiana is a naturally occurring palm tree in Zimbabwe. The tree provides an importan... more Hyphaene petersiana is a naturally occurring palm tree in Zimbabwe. The tree provides an important supplementary source of income to the communities where it is found, with a high demand for foliage for making baskets and sap for wine making. Propagation is both by vegetative and sexual methods, however, sexual propagation is constrained by the inherent dormancy of the seeds. Breaking seed dormancy is also the first step towards developing a conservation programme for the tree. The effect of water soaking (for 12, 24 and 48 hours), chemical scarification (sulphuric acid for 10 minutes), de-husking (tegument removal), sand papering as well as chemical treatment (thiourea and potassium nitrate) were compared with untreated seeds (control). No germination was observed for seeds treated with sulphuric acid. Water soaking for 12 hours gave the highest germination (71.7%) although not significantly different to other treatments.
African Journal of Agricultural Research, 2018
African Crop Science Journal, 2019
African journal of agricultural research
Contamination of potato with soft rotting enterobacteria belonging to the Pectobacterium and dick... more Contamination of potato with soft rotting enterobacteria belonging to the Pectobacterium and dickeya geners is one of the biggest problems in potato production. Calcium plays an important role in minimising the severity and incidence of potato tuber soft rot in storage. This review gives a detailed assessment of the epidemiology of the pathogens and how calcium affects potato tuber soft rot in storage.
European Journal of Plant Pathology, 2012
Potato production globally is constrained by factors which cause substantial economic losses. The... more Potato production globally is constrained by factors which cause substantial economic losses. These can be in the form of biotic and abiotic factors. The greatest losses are due to diseases and some of the important bacterial diseases are tuber soft rot, blackleg and aerial stem rot in the field. Tuber soft rot also causes high economic losses in transit and in storage. These diseases are caused by Pectobacterium and Dickeya spp. These pectolytic bacteria have various overwintering sites such as plant debris, water and pupae of several insect species. The pathogens enter plant tissues through wounds, lenticels and stolon ends where they remain latent, or cause symptoms if conditions are conducive for disease development. In latent infections, the bacteria remain dormant until climatic conditions are favourable for symptom development. The pathogens secrete different isoforms of extracellular enzymes which can break down living and dead plant tissues. Conditions which favour disease ...
IOSR Journal of Agriculture and Veterinary Science, 2014
A survey to assess the distribution and impact of the potato blackleg/soft rot disease complex in... more A survey to assess the distribution and impact of the potato blackleg/soft rot disease complex in Zimbabwe was conducted from September 2009 to June 2010. Sixty-four questionnaires were collected from 9 potato growing areas in Zimbabwe. The farmers are aware of the existence of soft rot post-harvest decay, seed piece decay and blackleg disease. The most predominant management method for the (three) 3 diseases was the use of rotation cycles with various crops. Estimates of economic losses caused by the diseases ranged from <1 to 65% with the average being approximately 23%. The most popular cultivars grown in Zimbabwe are Amethyst and BP1, which were ranked as susceptible by more than 50% of the growers. The disease symptoms are more prevalent at temperatures between 15-20 ˚C with moist or humid conditions.