Assinapol NDEREYIMANA | Egerton University (original) (raw)

Papers by Assinapol NDEREYIMANA

Egyptian Journal of Biological Pest Control, 2019

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to t... more The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to tomato production in Rwanda. Laboratory bioassays were conducted to evaluate some commercial entomopathogenic fungi (EPF) formulations on T. absoluta larvae. The larvae, inside the leaf galleries, were obtained from the established tomato field. Commercial EPF: Metatech® WP [Metarhizium anisopliae (Metschn.) Sorok, Strain FCM Ar 23B3], Beauvitech® WP [Beauveria bassiana (Bals.) Vuill., Strain J25], and Botanigard ES [B. bassiana (Bals.), Strain GHA] were tested in Petri dishes against T. absoluta larvae at a concentration of 108 spores/ml. A synthetic insecticide, imidacloprid was included for comparison as a positive control, while water was used as a negative control. All the tested commercial EPF formulations were pathogenic to T. absoluta larvae in all conducted bioassays. Mortality rates increased with an increase in time (days). However, the insignificant difference was observed in ...

Egyptian Journal of Biological Pest Control, 2019

International Research Journal of Horticulture, 2014

Growth performance of eggplant (Solanum melongena L.) grafts was evaluated under different spacin... more Growth performance of eggplant (Solanum melongena L.) grafts was evaluated under different spacing and fertigation levels. The field trial was designed in a strip plot design with four levels of spacing (S1: 1 m x 1m, S2: 2 m x 1 m, S3: 1.5 m x 1.5 m and S4: 0.6 m x 0.6 m) and three levels of fertigation, F1: 75 % RDF (Recommended Dose of Fertilizer), F2: 100 % RDF and F3: 125 % RDF, replicated four times. Eggplant seedlings (not grafted) were planted also for comparison with grafts. The plant height, number of branches per plant and plant spread in East-West (EW) and North-South (NS) directions were recorded and subjected to analysis of variance using M Stat-C software package while the growth performance of eggplant grafts and seedlings were compared using t-test. The results indicated that grafting had high effect on plant growth parameters and increases in eggplant grafts over seedlings were 72.76, 48.13, 49.13 and 56.09 per cent for plant height, number of branches per plant, plant spread in EW and NS direction respectively. Moreover, spacing and fertigation levels significantly affected eggplant growth and excellent growth performance for eggplant grafts was noticed under 1.5 m x 1.5 m + 100 per cent RDF which is recommended at the end of this study. Eggplant growers should be encouraged use eggplant grafts in combination with adequate plant spacing and nutrition since these contribute to the improved plant growth and development leading to greater productivity.

Journal of Applied Horticulture, 2019

Advances in horticultural science, 2020

This study evaluated the effect of entomopathogens and plant extracts, used against Tuta absoluta,... more This study evaluated the effect of entomopathogens and plant extracts, used against Tuta absoluta, on growth, yield, and fruit quality of tomato. Two field trials were carried out in a randomised compled block design, replicated thrice. The treatments were Steinernema sp. RW14­M­C2a­3, Steinernema sp. RW14­M­C2a­3, Metatech®WP (Metarhizium anisopliae, Strain FCM Ar 23B3), Beauvitech®WP (Beauveria bassiana, Strain J25) as entomopathogens, Tephrosia vogelii and Phytolacca dodecandra as plant extracts, and azadirachtin 0.03% EC. Imidacloprid and water also were included as positive and negative controls, respectively. The best growth and yield parameters were recorded with the entomopathogens and azadirachtin, which were insignificantly different in most cases. The increase in yied of healthy fruit per plant (average of two trials) compared to the negative control (water spray) was 11.4, 10.8,10.1, 9.6, 3.96, 2.2, 11.7 and 2.4 folds for Steinernema sp. RW14M­C2a­3, Steinernema sp. RW14­M­C...

A study was conducted to find out the effect of grafting, plant spacing and fertigation levels on... more A study was conducted to find out the effect of grafting, plant spacing and fertigation levels on eggplant fruit quality parameters. Eggplant (Solanum melongena L.) F1 hybrid COBH 2 was grafted on Solanum torvum. The obtained grafts were evaluated in a strip plot design with four spacing levels (S1: 1 m x 1m, S2: 2 m x 1 m, S3: 1.5 m x 1.5 m and S4: 0.6 m x 0.6 m) and three fertigation levels, F1: 75 % RDF (Recommended Dose of Fertilizer), F2: 100 % RDF and F3: 125 % RDF, and four replications. After six months, the plants were pruned to obtain the ratoon crop which lasted four months. Seedlings (not grafted) were planted in first season for comparison with main crop of grafts. The data for dry matter, protein, ascorbic acid, total phenols and solasodine contents in eggplant's fruits were recorded and the analysis of variance was performed while t-test was conducted to compare grafts and seedlings. The results indicated that apart from solasodine content, with an average of 0.02...

Advances in Horticultural Science

This study was carried out to determine the effect of vine and fruit pruning on watermelon (Citru... more This study was carried out to determine the effect of vine and fruit pruning on watermelon (Citrullus lanatus) yield. Five pruning methods: P1=no pruning at all, P2=pruning to four vines with two fruits per vine, P3=pruning to four vines with one fruit per vine, P4=pruning to three vines with two fruits per vine and P5=pruning to three vines with one fruit per vine were evaluated on two watermelon cultivars: ‘Sugar baby’ and ‘Julie F1’ under a factorial randomized complete block design with three replications. Investigations were carried out in the seasons 2017A (short rains) and 2017B (long rains) at Karama and Rubona experimental sites belonging to Rwanda Agriculture and Animal Resources Development Board. The obtained results indicated a significant difference among the different cultivars and pruning methods tested during both seasons and at two sites. Generally, all studied parameters recorded higher values during season 2017B than in season 2017A at Rubona site. A similar tren...

Fundamental and Applied Agriculture

Journal of Cleaner Production

International Research Journal of Horticulture, 2014

Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its p... more Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its production is challenged by the tomato leaf miner (Tuta absoluta Meyrick), an invasive pest. Synthetic insecticides which are primarily used for its control, have various drawbacks. Bioactivity of Tephrosia vogelii, Tithonia diversifolia, Vernonia amygdalina and Phytolacca dodecandra aqueous extracts was evaluated against T. absoluta in laboratory. Leaflets with third instar larvae (3.85-5.65 mm) of T. absoluta in mines were collected from established tomato field. Aqueous plants extracts were evaluated at a dose of 10 % weight/volume. Sterile tap water and azadirachtin 0.03 % EC were used as negative and positive controls, respectively. Petri-dishes of 9 cm diameter (n=10) were used as bioassay arenas in a completely randomized design with four replications. Data on larval mortality were collected every 24 h for 5 days. Three bioassays were conducted on different dates. Results indicated that tested plant extracts exhibited a capacity to kill T. absoluta larvae in tomato leaf galleries with significant difference among them (P <0.0001). The killing capacity increased with exposure time. At 24 h of exposure, T. absoluta larvae mortality was in a range of 35.0-37.5 % for azadirachtin and 5.0-10.0 % for T. vogelii while all other aqueous extracts had 0.0 % mortality, except V. amygdalina which recorded 2.5 % in bioassay one. In all bioassays, the lowest mortality recorded 5 days after treatments with T. vogelii, T. diversifolia, V. amygdalina, P. dodecandra and azadirachtin was 32.2, 2.8. 2.5, 20.5 and 97.5 % while the highest mortality at this time was 35.1, 10.6, 13.3, 24.9 and 100 %, respectively. Tephrosia vogelii and P. dodecandra, which recorded higher efficacy compared to the other local plants, should be advanced to field evaluation. The observed higher efficacy of azadirachtin to Rwandan population of T. absoluta should also be confirmed under field conditions.

Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its p... more Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its production is challenged by the tomato leaf miner (Tuta absoluta Meyrick), an invasive pest. Synthetic insecticides which are primarily used for its control, have various drawbacks. Bioactivity of Tephrosia vogelii, Tithonia diversifolia, Vernonia amygdalina and Phytolacca dodecandra aqueous extracts was evaluated against T. absoluta in laboratory. Leaflets with third instar larvae (3.85-5.65 mm) of T. absoluta in mines were collected from established tomato field. Aqueous plants extracts were evaluated at a dose of 10 % weight/volume. Sterile tap water and azadirachtin 0.03 % EC were used as negative and positive controls, respectively. Petri-dishes of 9 cm diameter (n=10) were used as bioassay arenas in a completely randomized design with four replications. Data on larval mortality were collected every 24 h for 5 days. Three bioassays were conducted on different dates. Results indicated that tested plant extracts exhibited a capacity to kill T. absoluta larvae in tomato leaf galleries with significant difference among them (P <0.0001). The killing capacity increased with exposure time. At 24 h of exposure, T. absoluta larvae mortality was in a range of 35.0-37.5 % for azadirachtin and 5.0-10.0 % for T. vogelii while all other aqueous extracts had 0.0 % mortality, except V. amygdalina which recorded 2.5 % in bioassay one. In all bioassays, the lowest mortality recorded 5 days after treatments with T. vogelii, T. diversifolia, V. amygdalina, P. dodecandra and azadirachtin was 32.2, 2.8. 2.5, 20.5 and 97.5 % while the highest mortality at this time was 35.1, 10.6, 13.3, 24.9 and 100 %, respectively. Tephrosia vogelii and P. dodecandra, which recorded higher efficacy compared to the other local plants, should be advanced to field evaluation. The observed higher efficacy of azadirachtin to Rwandan population of T. absoluta should also be confirmed under field conditions.

5(2): 235–242, 2020

Simple and low cost farm technologies are required for small-scale farmers in developing countrie... more Simple and low cost farm technologies are required for small-scale farmers in developing countries to improve marketability and reduce postharvest losses of onion (Allium cepa L.) bulbs. Two experiments were conducted to evaluate the effect of curing and storage temperature on shelf life of onion bulbs. In the first experiment, the cured bulbs of yellow onion 'Shippo' were stored at five different temperature levels: 15°C, 20°C, 25°C and 30°C, and room condition (Rc) for 11 weeks from May to August 2015. It was arranged in a completely randomized design with twelve replications. In the second experiment, cured and non-cured red onion bulbs 'Shonan Red' were stored at four different temperature levels: 15°C, 20°C, 25°C and 30°C , for eight weeks from June to August 2015. It was arranged as a two factorial experiment with 10 replications. Onion shelf life was measured by recording weight loss, sprouted, rotten, and mould infected bulbs, as well as general appearance. The results indicated that curing treatment significantly reduced weight loss and rotting percentage, while maintaining high score of the general appearance. The non-cured bulbs stored at 30°C showed higher percentage of rotten bulbs (40%) after eight weeks of storage. On the other hand, in case of the cured onion bulbs, rotting and mould infection (%) were recorded only at 15°C. Sprouting of 8.3% bulb was observed only when stored at 20°C in the first experiment after nine weeks of storage. The obtained results suggest that onion bulbs should be cured and stored at 25−30°C for better marketability and longer shelf life. Further experiments can be conducted to evaluate the performance of cured bulbs for different onion cultivars stored in ambient conditions of Rwanda. Cite this article: Ndereyimana A, Koyama S, Kagiraneza B. 2020. Effect of curing and storage temperature on shelf life of onion (Allium cepa L.) bulbs. Fundamental and Applied Agriculture 5(2): 235-242.

Egyptian Journal of Biological Pest Control, 2019

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to t... more The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to tomato production in Rwanda. Laboratory bioassays were conducted to evaluate some commercial entomopathogenic fungi (EPF) formulations on T. absoluta larvae. The larvae, inside the leaf galleries, were obtained from the established tomato field. Commercial EPF: Metatech® WP [Metarhizium anisopliae (Metschn.) Sorok, Strain FCM Ar 23B3], Beauvitech® WP [Beauveria bassiana (Bals.) Vuill., Strain J25], and Botanigard ES [B. bassiana (Bals.), Strain GHA] were tested in Petri dishes against T. absoluta larvae at a concentration of 10 8 spores/ml. A synthetic insecticide, imidacloprid was included for comparison as a positive control, while water was used as a negative control. All the tested commercial EPF formulations were pathogenic to T. absoluta larvae in all conducted bioassays. Mortality rates increased with an increase in time (days). However, the insignificant difference was observed in the mortality of T. absoluta larvae treated with the commercial EPF during the first 3 days in all bioassays. Highly significant differences (p < 0.01) in pathogenicity among treatments were observed from the 4th to 6th days after inoculation. Metatech® WP and Beauvitech® WP recorded the highest mortality rates (82.8 and 60.8%) with the LT 50 values of 3.9 and 5.2 days, respectively, while imidacloprid caused the least larval mortality. Since the EPF demonstrated high virulence level against the target pest, the efficacy of Metatech® WP and Beauvitech® WP should be advanced to field evaluation to determine their potential as alternatives to the synthetic insecticides.

Journal of Applied Horticulure, 2019

Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda but its pr... more Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda but its production is challenged by the tomato leaf miner (Tuta absoluta Meyrick), an invasive pest. Synthetic insecticides which are the main method of its control have various drawbacks. Bioactivity of Tephrosia vogelii, Tithonia diversifolia, Vernonia amygdalina and Phytolacca dodecandra acqueous extracts was evaluated against T. absoluta in laboratory. Leaflets with third instar larvae (3.85-5.65 mm) of T. absoluta in mines were collected from established tomato field. Aqueous plants extracts were evaluated at a dose of 10 % weight/volume. Sterile tap water and azadirachtin 0.03 % EC were used as negative and positive controls, respectively. Petri-dishes of 9 cm diametre (n=10) were used as bioassay arenas in a completely randomized design with four replications. Data on larvae mortality were collected every 24 h for a period of 5 days. Three bioassays were conducted on different dates. Results indicated that tested plant extracts exhibited a capacity to kill T. absoluta larvae in tomato leaf galleries with significant difference among them (P < 0.0001). The killing capacity increased with exposure time. At 24 h of exposure, T. absoluta larvae mortality was in a range of 35.0-37.5 % for azadirachtin and 5.0-10.0 % for T. vogelii while all other aqueous extracts had 0.0 % mortality, except V. amygdalina which recorded 2.5 % in bioassay one. In all bioassays, the lowest mortality recorded 5 days after treatments with T. vogelii, T. diversifolia, V. amygdalina, P. dodecandra and azadirachtin was 32.2, 2.8. 2.5, 20.5 and 97.5 % while the highest mortality at this time was 35.1, 10.6, 13.3, 24.9 and 100 %, respectively. Tephrosia vogelii and P. dodecandra which recorded higher efficacy compared to the other local plants should be advanced to field evaluation. The observed higher efficacy of azadirachtin to Rwandan population of T. absoluta should also be confirmed under field conditions.

Egyptian Journal of Biological Pest Control, 2019

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to t... more The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to tomato production in Rwanda. Laboratory bioassays were conducted to evaluate some commercial entomopathogenic fungi (EPF) formulations on T. absoluta larvae. The larvae, inside the leaf galleries, were obtained from the established tomato field. Commercial EPF: Metatech® WP [Metarhizium anisopliae (Metschn.) Sorok, Strain FCM Ar 23B3], Beauvitech® WP [Beauveria bassiana (Bals.) Vuill., Strain J25], and Botanigard ES [B. bassiana (Bals.), Strain GHA] were tested in Petri dishes against T. absoluta larvae at a concentration of 108 spores/ml. A synthetic insecticide, imidacloprid was included for comparison as a positive control, while water was used as a negative control. All the tested commercial EPF formulations were pathogenic to T. absoluta larvae in all conducted bioassays. Mortality rates increased with an increase in time (days). However, the insignificant difference was observed in ...

Egyptian Journal of Biological Pest Control, 2019

International Research Journal of Horticulture, 2014

Growth performance of eggplant (Solanum melongena L.) grafts was evaluated under different spacin... more Growth performance of eggplant (Solanum melongena L.) grafts was evaluated under different spacing and fertigation levels. The field trial was designed in a strip plot design with four levels of spacing (S1: 1 m x 1m, S2: 2 m x 1 m, S3: 1.5 m x 1.5 m and S4: 0.6 m x 0.6 m) and three levels of fertigation, F1: 75 % RDF (Recommended Dose of Fertilizer), F2: 100 % RDF and F3: 125 % RDF, replicated four times. Eggplant seedlings (not grafted) were planted also for comparison with grafts. The plant height, number of branches per plant and plant spread in East-West (EW) and North-South (NS) directions were recorded and subjected to analysis of variance using M Stat-C software package while the growth performance of eggplant grafts and seedlings were compared using t-test. The results indicated that grafting had high effect on plant growth parameters and increases in eggplant grafts over seedlings were 72.76, 48.13, 49.13 and 56.09 per cent for plant height, number of branches per plant, plant spread in EW and NS direction respectively. Moreover, spacing and fertigation levels significantly affected eggplant growth and excellent growth performance for eggplant grafts was noticed under 1.5 m x 1.5 m + 100 per cent RDF which is recommended at the end of this study. Eggplant growers should be encouraged use eggplant grafts in combination with adequate plant spacing and nutrition since these contribute to the improved plant growth and development leading to greater productivity.

Journal of Applied Horticulture, 2019

Advances in horticultural science, 2020

This study evaluated the effect of entomopathogens and plant extracts, used against Tuta absoluta,... more This study evaluated the effect of entomopathogens and plant extracts, used against Tuta absoluta, on growth, yield, and fruit quality of tomato. Two field trials were carried out in a randomised compled block design, replicated thrice. The treatments were Steinernema sp. RW14­M­C2a­3, Steinernema sp. RW14­M­C2a­3, Metatech®WP (Metarhizium anisopliae, Strain FCM Ar 23B3), Beauvitech®WP (Beauveria bassiana, Strain J25) as entomopathogens, Tephrosia vogelii and Phytolacca dodecandra as plant extracts, and azadirachtin 0.03% EC. Imidacloprid and water also were included as positive and negative controls, respectively. The best growth and yield parameters were recorded with the entomopathogens and azadirachtin, which were insignificantly different in most cases. The increase in yied of healthy fruit per plant (average of two trials) compared to the negative control (water spray) was 11.4, 10.8,10.1, 9.6, 3.96, 2.2, 11.7 and 2.4 folds for Steinernema sp. RW14M­C2a­3, Steinernema sp. RW14­M­C...

A study was conducted to find out the effect of grafting, plant spacing and fertigation levels on... more A study was conducted to find out the effect of grafting, plant spacing and fertigation levels on eggplant fruit quality parameters. Eggplant (Solanum melongena L.) F1 hybrid COBH 2 was grafted on Solanum torvum. The obtained grafts were evaluated in a strip plot design with four spacing levels (S1: 1 m x 1m, S2: 2 m x 1 m, S3: 1.5 m x 1.5 m and S4: 0.6 m x 0.6 m) and three fertigation levels, F1: 75 % RDF (Recommended Dose of Fertilizer), F2: 100 % RDF and F3: 125 % RDF, and four replications. After six months, the plants were pruned to obtain the ratoon crop which lasted four months. Seedlings (not grafted) were planted in first season for comparison with main crop of grafts. The data for dry matter, protein, ascorbic acid, total phenols and solasodine contents in eggplant's fruits were recorded and the analysis of variance was performed while t-test was conducted to compare grafts and seedlings. The results indicated that apart from solasodine content, with an average of 0.02...

Advances in Horticultural Science

This study was carried out to determine the effect of vine and fruit pruning on watermelon (Citru... more This study was carried out to determine the effect of vine and fruit pruning on watermelon (Citrullus lanatus) yield. Five pruning methods: P1=no pruning at all, P2=pruning to four vines with two fruits per vine, P3=pruning to four vines with one fruit per vine, P4=pruning to three vines with two fruits per vine and P5=pruning to three vines with one fruit per vine were evaluated on two watermelon cultivars: ‘Sugar baby’ and ‘Julie F1’ under a factorial randomized complete block design with three replications. Investigations were carried out in the seasons 2017A (short rains) and 2017B (long rains) at Karama and Rubona experimental sites belonging to Rwanda Agriculture and Animal Resources Development Board. The obtained results indicated a significant difference among the different cultivars and pruning methods tested during both seasons and at two sites. Generally, all studied parameters recorded higher values during season 2017B than in season 2017A at Rubona site. A similar tren...

Fundamental and Applied Agriculture

Journal of Cleaner Production

International Research Journal of Horticulture, 2014

Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its p... more Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its production is challenged by the tomato leaf miner (Tuta absoluta Meyrick), an invasive pest. Synthetic insecticides which are primarily used for its control, have various drawbacks. Bioactivity of Tephrosia vogelii, Tithonia diversifolia, Vernonia amygdalina and Phytolacca dodecandra aqueous extracts was evaluated against T. absoluta in laboratory. Leaflets with third instar larvae (3.85-5.65 mm) of T. absoluta in mines were collected from established tomato field. Aqueous plants extracts were evaluated at a dose of 10 % weight/volume. Sterile tap water and azadirachtin 0.03 % EC were used as negative and positive controls, respectively. Petri-dishes of 9 cm diameter (n=10) were used as bioassay arenas in a completely randomized design with four replications. Data on larval mortality were collected every 24 h for 5 days. Three bioassays were conducted on different dates. Results indicated that tested plant extracts exhibited a capacity to kill T. absoluta larvae in tomato leaf galleries with significant difference among them (P <0.0001). The killing capacity increased with exposure time. At 24 h of exposure, T. absoluta larvae mortality was in a range of 35.0-37.5 % for azadirachtin and 5.0-10.0 % for T. vogelii while all other aqueous extracts had 0.0 % mortality, except V. amygdalina which recorded 2.5 % in bioassay one. In all bioassays, the lowest mortality recorded 5 days after treatments with T. vogelii, T. diversifolia, V. amygdalina, P. dodecandra and azadirachtin was 32.2, 2.8. 2.5, 20.5 and 97.5 % while the highest mortality at this time was 35.1, 10.6, 13.3, 24.9 and 100 %, respectively. Tephrosia vogelii and P. dodecandra, which recorded higher efficacy compared to the other local plants, should be advanced to field evaluation. The observed higher efficacy of azadirachtin to Rwandan population of T. absoluta should also be confirmed under field conditions.

Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its p... more Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda, but its production is challenged by the tomato leaf miner (Tuta absoluta Meyrick), an invasive pest. Synthetic insecticides which are primarily used for its control, have various drawbacks. Bioactivity of Tephrosia vogelii, Tithonia diversifolia, Vernonia amygdalina and Phytolacca dodecandra aqueous extracts was evaluated against T. absoluta in laboratory. Leaflets with third instar larvae (3.85-5.65 mm) of T. absoluta in mines were collected from established tomato field. Aqueous plants extracts were evaluated at a dose of 10 % weight/volume. Sterile tap water and azadirachtin 0.03 % EC were used as negative and positive controls, respectively. Petri-dishes of 9 cm diameter (n=10) were used as bioassay arenas in a completely randomized design with four replications. Data on larval mortality were collected every 24 h for 5 days. Three bioassays were conducted on different dates. Results indicated that tested plant extracts exhibited a capacity to kill T. absoluta larvae in tomato leaf galleries with significant difference among them (P <0.0001). The killing capacity increased with exposure time. At 24 h of exposure, T. absoluta larvae mortality was in a range of 35.0-37.5 % for azadirachtin and 5.0-10.0 % for T. vogelii while all other aqueous extracts had 0.0 % mortality, except V. amygdalina which recorded 2.5 % in bioassay one. In all bioassays, the lowest mortality recorded 5 days after treatments with T. vogelii, T. diversifolia, V. amygdalina, P. dodecandra and azadirachtin was 32.2, 2.8. 2.5, 20.5 and 97.5 % while the highest mortality at this time was 35.1, 10.6, 13.3, 24.9 and 100 %, respectively. Tephrosia vogelii and P. dodecandra, which recorded higher efficacy compared to the other local plants, should be advanced to field evaluation. The observed higher efficacy of azadirachtin to Rwandan population of T. absoluta should also be confirmed under field conditions.

5(2): 235–242, 2020

Simple and low cost farm technologies are required for small-scale farmers in developing countrie... more Simple and low cost farm technologies are required for small-scale farmers in developing countries to improve marketability and reduce postharvest losses of onion (Allium cepa L.) bulbs. Two experiments were conducted to evaluate the effect of curing and storage temperature on shelf life of onion bulbs. In the first experiment, the cured bulbs of yellow onion 'Shippo' were stored at five different temperature levels: 15°C, 20°C, 25°C and 30°C, and room condition (Rc) for 11 weeks from May to August 2015. It was arranged in a completely randomized design with twelve replications. In the second experiment, cured and non-cured red onion bulbs 'Shonan Red' were stored at four different temperature levels: 15°C, 20°C, 25°C and 30°C , for eight weeks from June to August 2015. It was arranged as a two factorial experiment with 10 replications. Onion shelf life was measured by recording weight loss, sprouted, rotten, and mould infected bulbs, as well as general appearance. The results indicated that curing treatment significantly reduced weight loss and rotting percentage, while maintaining high score of the general appearance. The non-cured bulbs stored at 30°C showed higher percentage of rotten bulbs (40%) after eight weeks of storage. On the other hand, in case of the cured onion bulbs, rotting and mould infection (%) were recorded only at 15°C. Sprouting of 8.3% bulb was observed only when stored at 20°C in the first experiment after nine weeks of storage. The obtained results suggest that onion bulbs should be cured and stored at 25−30°C for better marketability and longer shelf life. Further experiments can be conducted to evaluate the performance of cured bulbs for different onion cultivars stored in ambient conditions of Rwanda. Cite this article: Ndereyimana A, Koyama S, Kagiraneza B. 2020. Effect of curing and storage temperature on shelf life of onion (Allium cepa L.) bulbs. Fundamental and Applied Agriculture 5(2): 235-242.

Egyptian Journal of Biological Pest Control, 2019

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to t... more The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a major threat to tomato production in Rwanda. Laboratory bioassays were conducted to evaluate some commercial entomopathogenic fungi (EPF) formulations on T. absoluta larvae. The larvae, inside the leaf galleries, were obtained from the established tomato field. Commercial EPF: Metatech® WP [Metarhizium anisopliae (Metschn.) Sorok, Strain FCM Ar 23B3], Beauvitech® WP [Beauveria bassiana (Bals.) Vuill., Strain J25], and Botanigard ES [B. bassiana (Bals.), Strain GHA] were tested in Petri dishes against T. absoluta larvae at a concentration of 10 8 spores/ml. A synthetic insecticide, imidacloprid was included for comparison as a positive control, while water was used as a negative control. All the tested commercial EPF formulations were pathogenic to T. absoluta larvae in all conducted bioassays. Mortality rates increased with an increase in time (days). However, the insignificant difference was observed in the mortality of T. absoluta larvae treated with the commercial EPF during the first 3 days in all bioassays. Highly significant differences (p < 0.01) in pathogenicity among treatments were observed from the 4th to 6th days after inoculation. Metatech® WP and Beauvitech® WP recorded the highest mortality rates (82.8 and 60.8%) with the LT 50 values of 3.9 and 5.2 days, respectively, while imidacloprid caused the least larval mortality. Since the EPF demonstrated high virulence level against the target pest, the efficacy of Metatech® WP and Beauvitech® WP should be advanced to field evaluation to determine their potential as alternatives to the synthetic insecticides.

Journal of Applied Horticulure, 2019

Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda but its pr... more Tomato (Solanum lycopersicum L.) is economically and nutritionally important in Rwanda but its production is challenged by the tomato leaf miner (Tuta absoluta Meyrick), an invasive pest. Synthetic insecticides which are the main method of its control have various drawbacks. Bioactivity of Tephrosia vogelii, Tithonia diversifolia, Vernonia amygdalina and Phytolacca dodecandra acqueous extracts was evaluated against T. absoluta in laboratory. Leaflets with third instar larvae (3.85-5.65 mm) of T. absoluta in mines were collected from established tomato field. Aqueous plants extracts were evaluated at a dose of 10 % weight/volume. Sterile tap water and azadirachtin 0.03 % EC were used as negative and positive controls, respectively. Petri-dishes of 9 cm diametre (n=10) were used as bioassay arenas in a completely randomized design with four replications. Data on larvae mortality were collected every 24 h for a period of 5 days. Three bioassays were conducted on different dates. Results indicated that tested plant extracts exhibited a capacity to kill T. absoluta larvae in tomato leaf galleries with significant difference among them (P < 0.0001). The killing capacity increased with exposure time. At 24 h of exposure, T. absoluta larvae mortality was in a range of 35.0-37.5 % for azadirachtin and 5.0-10.0 % for T. vogelii while all other aqueous extracts had 0.0 % mortality, except V. amygdalina which recorded 2.5 % in bioassay one. In all bioassays, the lowest mortality recorded 5 days after treatments with T. vogelii, T. diversifolia, V. amygdalina, P. dodecandra and azadirachtin was 32.2, 2.8. 2.5, 20.5 and 97.5 % while the highest mortality at this time was 35.1, 10.6, 13.3, 24.9 and 100 %, respectively. Tephrosia vogelii and P. dodecandra which recorded higher efficacy compared to the other local plants should be advanced to field evaluation. The observed higher efficacy of azadirachtin to Rwandan population of T. absoluta should also be confirmed under field conditions.