Influence of plant and residue age on attraction, acceptance and larval survival of the banana weevil Cosmopolites sordidus (Coleoptera: Curculionidae)

Laboratory trials were conducted in Uganda at the Kawanda Agricultural Research Institute to determine attraction, eclosion success and larval survivorship of the banana weevil Cosmopolites sordidus (Germar) on crop residues of different ages. In the first experiment, studies focused on different types and ages of residues of one susceptible highland banana clone ‘Nabusa’ (genome group AAA-EA). Corms attracted 65% of the test weevils, pseudostems 30%, while 5% were non-respondents. Oviposition levels and the number of eggs per female were higher on young than old corms. Eclosion rates of 30 DAH. To assess immature survival, 30 DAH. Larval duration and mean days taken for adult emergence increased with plant and crop residue age. Females emerging from the different plant and residues treatments were similar in weight. The data suggest that all aged residues are suitable hosts for C. sordidus, suggesting that sanitation practices should be implemented soon after harvest

Quantifying Physical and Economic Losses of African Indigenous Vegetable Solanum aethiopicum Along the Commercial Supply Value Chain

This paper is based on research work done by the authors on African Indigenous vegetables with financial support from the European Union and Forum for Agricultural Research in Africa (FARA) through its Promoting African & European Partnerships in Agricultural Research & Development (PAEPARD). This is part of the outputs of the project entitled “Enhancing nutrition security and incomes through adding value to indigenous vegetables in East and Central Uganda”. Abstract This study presents results of a research that was conducted in Uganda to expound the issues of Solanum aethopicum (Nakati) value chain supply, physical and economic quantification of losses in the supply chain. Specifically the study was designed to; (i) identify and map the value chain actors of an indigenous leafy vegetable S. aethiopicum production and marketing and (ii) quantify the physical losses along the S. aethiopicum vegetable supply chain and (iii) estimate the economic losses along the S. aethiopicum vegetable supply chain.A Participatory Rural Appraisal (PRA) was conducted at Namulonge, Kabanyoro, Busukuma and Zirobwe villages on 7th August 2016, 9th August 2016, 10th August 2016 and 12th August 2016, respectively with the farmers to understand the S. aethiopicum actors’ perception of value chain vegetable losses and mitigating solutions. At each supply chain stage namely field, transit, wholesale and retail. The losses were expressed as difference of the weight of vegetables that entered each stage and weighed again  when the value adding  stage is completed which became the quantity that enters the subsequent stage, thus the losses were determined as a percentage of those that never went to market in relation to the total potential from the field.The value chain actor mapping has revealed a short a short value chain with a number of value chain actors namely; 60 input suppliers, 40 farmer groups, 42 wholesalers, 48 retailers, 2 processors and 61 transporters.  With the exception of agro input supply node which handle pesticides, the rest of the actors handle fresh leafy vegetables that are prone to heavy weight losses due to wilting, rotting and transit contamination. The study further indicated that the physical quantities of S. aethopicum harvested varied in different farms, nonetheless, on average 1473.3 kgs per acre of S. aethopicum is harvested and of the harvested vegetables, 69.4kgs and 73.7 kgs get lost in the field and marketing process, respectively. This translates into S. aethopicum vegetable losses of 13.3% and 5.2% in the field and market points, respectively. Most of this loss occurred on-farm with 13.3% of the harvested crop not entering the commercial-supply chain followed by retail level, 3.5% losses and least at wholesale level of 1.7%. In terms of economic losses, sale of S. aethopicum earned farmers on average 567,233 Shs per acre, sizeable revenue of 26,700 Shs and 53,192 Shs get lost in the field and marketing process, respectively. This is equivalent to S. aethopicum revenue losses of 18% and 35.9% in the field and market points, respectively. Overall, 79,892 Shs of S. aethopicum revenues was lost in the commercial supply chain constituting 53.9% of the losses. Break down of revenue losses showed that at farm level, the loss is 18%, at wholesale level the losses are 10.2% and at retail level losses are 25.7%.It therefore can be concluded that there is a high physical and economic losses of leafy S. aethopicum vegetables at different stages in the supply chain. More research efforts could be focussed on technologies that reduce post-harvest losses such as drying and minimal processing technologies at farm level where greatest losses are experienced. Keywords: African indigenous vegetables, supply chain, economic loss, physical losses DOI: 10.7176/JESD/10-2-0

Postharvest practices along supply chains of Solanum Aethiopicum (shum) and Amaranthus lividus (linn) leafy vegetables in Wakiso and Kampala Districts, Uganda

A cross-sectional study design was employed for the purpose of understanding the postharvest practices and entry point for losses  along the supply chains of Solanum aethiopicum and Amaranthus lividus leafy vegetables. This is important so that interventions along the supply chain may not be misplaced. The target population included chain actors: farmers (n=10), traders (n=30) and key informants (n=7) who were selected purposively for interviews. A total of 10 farms and 7 market visits were made along the two supply routes: Kabubbu-Kalerwe and Kabubbu-Kireka. Data were collected using a semi-structured questionnaire and key informant checklist. Two supply chains were observed in this study: short supply chain where the farmer doubled as a trader. Farmers in this category were the majority (90%). In the long type, farmers (10%) supplied middlemen/transporters who then delivered to the markets. Furthermore, there were no exports or value addition in either of the supply chains. A good hygiene practice observed on the farm was that of trimming off the roots of vegetables to reduce contamination from the soil and also the amount of garbage generated in the market. Packing of vegetables on hired trucks was a common practice where roots/leaves faced each other to prevent soiling of the leaves by the roots. The main transport means used was truck (100%) with alternative transportation means being motorcycle and bicycles. The cool evening hours (20:00 to 00:00hrs) were the most preferred transportation times. The packaging method observed in the market was use of either black or white polythene bags at the point of sale with only 53.3% of the traders packaging for their customers. There was no proper packaging and storage both on the farms and in the markets. Traders in the markets either sprinkled water on the leftover vegetables or covered them with a wet sack as a preservation method. Moreover,  only 16.6% sorted and graded their vegetables whereas 83.4% did not. There was inappropriate handling, storage and packaging practices along the two supply chains. Key words: handling, transport, packaging, storage, leafy vegetables, supply chain, chain  actor

Effect of post-harvest handling practices, storage technologies and packaging material on post-harvest quality and antioxidant potential of Solanum Aethiopicum (Shum) leafy vegetable

Several studies have supported the use of vegetables as foods as well as medicinal plants. However, most especially for the leafy types of vegetables, their high moisture content gives them a short shelf life. On average Solanum aethiopicum (Shum) has a shelf life of one day, making it unable to keep fresh for a long time. The objective of this study was to determine the effect of post-harvest handling practices and storage technology on the post-harvest quality and antioxidant activity in S. aethiopicum, as well as determine the packaging material that could be able to maintain a high post-harvest quality during storage. The post-harvest handling and storage technologies were tested under three experimental conditions. Experiment one involved placing 2.0 kg of the harvested S. aethiopicum with roots intact (RI) and others with roots cut-off (RC) in a charcoal cooler (-CC), 21.0±1.00 °C, 95.67±3.01 %rh; in ambient storage (-AC), 23.8±2.86 °C, 69.38±6.72 % rh; and in cold room (-CR), 7.17±1.30 °C, 95.80±3.19 %rh. Experiment two involved storing 2.0 kg of S. aethiopicum in charcoal cooler with no water treatment (TT-) and in ambient storage while immersing in portable water for 2 to 3 seconds during the day (TT+). Experiment three involved packing 1.0 kg of S. aethiopicum sample of both RC and RI state to assess the effectiveness of the packaging materials (0.1 cm meshed perforated polyethylene (RC0.1), 0.5 cm meshed perforated polyethylene (RC0.5) and a 60 μm perforated polyethylene (RC60μm) in maintaining quality of the vegetables. The edible parts of the vegetable were tested for moisture content, percentage weight loss, chlorophyll content, polyphenol content and total antioxidant activity (as measures of post-harvest quality and shelf life) after every 24 hours. The antioxidant activity was determined by screening for free radical scavenging properties using diphenyl picryl hydrazyl (DPPH), Ferric reducing antioxidant power (FRAP) and ascorbic acid as standard. The results revealed that Shelf life was found to increase (from one day to four days) when the vegetable was intermittently immersed in portable water for 2 to 3 seconds after every one hour during the day for vegetables in ambient storage both with roots intact (RI(TT+)-AC and with roots cut-off RC(TT+)-AC). The samples stored in cold room and charcoal cooler showed slow and comparable reduction (percent) of weight for both intact and roots cut. The chlorophyll content decreased in all storage conditions, with ambient conditions showing the most rapid decrease. The total polyphenol fluctuated within relatively small limits for both with intact and roots cut-off when stored in cold room and charcoal cooler (6.25±0.05 to 9.35±0.05 mgGAE/gfw; respectively) within the four days of storage. Storage in ambient conditions indicated an increase in total polyphenol content from 9.35±0.05 to 14.77±0.12 mgGAE/gfw for that with roots intact (RI-AC) and to 13.65±0.06 mgGAE/gfw for roots cut-off (RC-AC). The increase in total polyphenol content in the ambient storage led to increased total antioxidant activity compared to that stored in cold room and charcoal cooler that remained almost constant. The 60 μm perforated polyethylene and 0.1 cm meshed perforated polyethylene retained more moisture (84.55±0.18 % and 85.20±0.03 %; respectively) and showed minimal percentage of weight loss (9.69±0.25 %) with the highest chlorophyll content (8.06±0.02 mg/g dwb) on day four when stored in the charcoal cooler, making it the best tested packaging material

Antioxidant potential of the farmer preferred selections of Solanum aethiopicum vegetable consumed in central Uganda

In addition to the rich micronutrient value, indigenous vegetables are regarded as possessing medicinal attributes. The Solanaceae family has over 1000 species worldwide, with a number of indigenous species originating in Africa. The most popular leafy vegetable in Uganda is the Solanum aethiopicum (Nakati). The objective of this study was to determine the selected phytochemical attributes, chlorophyll content, moisture content and total antioxidant activity of the farmer preferred selections within the landraces of Solanum aethiopicum leafy vegetable in Uganda. The antioxidant activity was achieved by screening the leaf extracts for their free radical scavenging properties using diphenyl picryl hydrazyl (DPPH) and ascorbic acid as standard. The ability of the extracts to scavenge DPPH radical was determined spectrophometrically at 517nm.The study showed that all the landraces had a high polyphenol and flavonoid content with SAS185/P/2015 containing the highest flavonoid content (3.16±0.06 mg QE/g fw). SAS1641/2015 showed the highest total polyphenol content of 7.79±0.27 mg GAE/g fw and also showed the highest vitamin C content. This contributed to the high total antioxidant activity of 2.79±0.01 and 5.43±0.02 mg AAE/g fw when using FRAP and DPPH methods respectively. SAS145/2015 presented the highest chlorophyll content of 19.69±0.01 mg/g dwb. All the landraces showed a high percentage moisture content that ranged from 82.66±0.35 to 84.21±0.48%. These results are of nutraceutical significance and hence confirm their usage as medicinal vegetables

Effect of crop sanitation on banana weevil Cosmopolites sordidus (Germar) populations and associated damage

The banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) is a serious pest of bananas. However, its ecology is not well elucidated especially in East Africa where plantations are up to 50 years old and are under various management and cropping systems. No single satisfactory control strategy has been found. Detailed information on C. sordidus biology and ecology is needed to explain the population dynamics of this pest in order to develop a comprehensive package for the small-scale farmer to alleviate the pest problem. Cultural control forms the first line of defence in pest control. For instance, removal of crop residues after harvest by chopping is a widely recommended cultural strategy for C. sordidus control. However, the actual effect of these practices on the insect's population dynamics is not clear. This study was aimed at investigating the effect of crop sanitation on population dynamics of C. sordidus and its associated damage.Laboratory and field studies on the biology and ecology of this pest on crop residues were conducted in Uganda. We found that corms are most attractive to the weevils than any other type of crop residues. Oviposition occurred on residues up to 120 days after harvest, but mainly on freshly harvested residues up to 30 days, implying that residues should be left up to a month before destroying them.In the study on survivorship of C. sordidus in crop residues, our results revealed that the pest successfully completes its life cycle within crop residues and emerging adults from different aged residues are equally fit. As crop residues can be a source of C. sordidus infestation to the standing crop, they need to be destroyed. There is a general belief that covering banana stumps after harvest helps reduce weevils in banana farms. However, there was no data available to prove that this practice is useful. Moreover, the real effect of covering stumps remained unknown. Our studies reveal that covering banana stumps after harvest reduces oviposition on them in the wet season, but encourages oviposition in the dry season. Therefore, farmers may cover the stumps in the wet but not in the dry season. Also, our studies suggest that covering all stumps in the wet season may encourage C. sordidus to oviposit on the crop. Therefore, some residues should be left in the inter-mat alleys to attract weevils away from the crop. The residues can then be destroyed after three to four weeks.Removal and chopping crop residues in farmers' fields helped to keep C. sordidus populations and damage lower than when the residues were left to accumulate. In comparison, removal of all residues in young closed banana plots reduced C. sordidus populations but increased damage on growing plants and reduced the levels of natural enemies. The implications of these results on the role of crop sanitation in the integrated management of C. sordidus are discussed.</p

Comparative control of the banana weevil, Cosmopolites sordidus, by the fungal pathogen, Beauveria bassiana, and some insecticides when used in combination with pseudostem trapping

Field evaluation was made of the effect of the fungal pathogen, Beauveria bassiana (Bals.) Vuillemin (Isolate KB/91/3), and Dursban, Primicid and Furadan insecticides on the banana weevil, Cosmopolites sordidus Germar. When the treatments were combined with pseudostem trapping, population of the banana weevil declined sharply. In the first four weeks after application, B. bassiana did not cause significant mortality of the weevil, while high mortalities were recorded for the insecticides, particularly Dursban. Monitored over a longer period (2-5 months), however, all the treatments significantly (P&lt;0.05) suppressed weevil population compared to the control. Beauveria bassiana was more persistent than the chemical insecticides, particularly when used without pseudostem traps. It is suggested that comprehensive field trials be carried out to confirm the findings of this study.Une evaluation a ete menee sur le champ sur l'effet du pathogene fungale, Beauveria bassiana (Bals.) Vuillemin (Isolate KB/9113), et les insecticides appelees Dursban, Primicide et Furadan utilisees sur les charancons de la banane, Germar cosmopolites sordidus. Quand les traitements etaient combines avec les signes du pseudostem, la population des charancons de la banane a connu un moindre declin. Au cours de la premiere semaine de la mise en application, B. Bassiana n'a pas cause de cas des mortalites considerables de charancons alors que des cas des mortalites elevees etaient remarques du cote insecticides, plus particulierement le Dursban. Apres un controle pendant une longue periode (de 2 a 5 mois), il ya eu cependant, tous les traitements qui ont considerablement domine la population des charancons (P&lt;0.05). Le type Beauveria bassiana etait plus persistant que les autres produits chimiques d'insecticides, particulierement lors qu'ils sont utilises avec les pieges pseudostem. Il a ete conseille que les essaies complets soient menes pour determiner les resultats de cette recherche

Distribution, timing of attack, and oviposition of the banana weevil, Cosmopolites sordidus, on banana crop residues in Uganda

Crop sanitation (removal and chopping of residue corms and pseudostems following plant harvest) has been recommended as a 'best bet' means of reducing banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), populations. However, it has been unclear when such practices should be carried out and what types of residues should be destroyed. Therefore, trials were conducted in Uganda to determine C. sordidus distribution, timing of attack, and oviposition on crop residues and growing plants. Assessments were performed in on-station trials on different aged standing and prostrate residues by destructive sampling. Similar data were collected from farmers' fields maintained at low, moderate, and high levels of sanitation. In the on-station trial, oviposition occurred on up to 120-day-old residues, although most occurred within 30 days of harvest. In a second on-station experiment, oviposition on standing residues was not significantly affected by residue age. By contrast, oviposition on prostrate residues was two times higher on 4-week-old than on 2-week-old residues, while the number of larvae on 8-week-old residues was three times higher than on 2-week-old residues. The number of adults was twice as high on 16-week-old residues as that on 2-week-old residues for both prostrate and standing residues. Farmers' fields maintained at high sanitation had 50% fewer eggs per residue than farms with low sanitation levels. In general, the number of immatures per residue was 50% higher on banana corms than on pseudostems. Numbers of larvae per residue were three times more abundant at low than at high sanitation levels. Residues in fields with high sanitation supported 50% fewer adults than residues in low sanitation fields. The results suggest that removal and splitting of corms after harvest is effective and practical in destroying immature growth stages of the pest and that such practices should be carried out soon after harves

Effects of crop sanitation on banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), populations and crop damage in Uganda

Crop sanitation, i.e. destruction of crop residues, has been hypothesized to lower banana weevil damage by removing adult refuges and breeding sites. Although it has been widely recommended to farmers, limited data are available to demonstrate the efficacy of this method. The effects of crop sanitation on banana weevil populations and damage were studied in an on-station trial in Uganda. Treatments included low, moderate and high levels of sanitation. Banana weevil populations, estimated by trapping and mark and recapture methods, were lowest in the high sanitation treatment. However, banana weevil damage was either not significantly different among treatments or lower in low sanitation treatments. Similarly, increases in crop sanitation level were not reflected in higher yields. The data from this trial suggest that crop sanitation is not an effective means of managing banana weevil and contrasts with results from an on-farm study in which sanitation reduced both weevil numbers and damage. Possible factors explaining the different outcomes of the two studies are discussed

Influence of plant and residue age on attraction, acceptance and larval survival of the banana weevil Cosmopolites sordidus (Coleoptera: Curculionidae)

Laboratory trials were conducted in Uganda at the Kawanda Agricultural Research Institute to determine attraction, eclosion success and larval survivorship of the banana weevil Cosmopolites sordidus (Germar) on crop residues of different ages. In the first experiment, studies focused on different types and ages of residues of one susceptible highland banana clone ‘Nabusa’ (genome group AAA-EA). Corms attracted 65% of the test weevils, pseudostems 30%, while 5% were non-respondents. Oviposition levels and the number of eggs per female were higher on young than old corms. Eclosion rates of 30 DAH. To assess immature survival, 30 DAH. Larval duration and mean days taken for adult emergence increased with plant and crop residue age. Females emerging from the different plant and residues treatments were similar in weight. The data suggest that all aged residues are suitable hosts for C. sordidus, suggesting that sanitation practices should be implemented soon after harvest