Droughts, pests, and diseases are among the most challenging production constraints facing smallholder potato farmers in Africa. The current study evaluated the response of potato cultivars to tuber pests and diseases under varied soil moisture regimes in a semi-arid region in Kenya. Sixteen potato varieties were subjected to field experimental screening in two seasons at two different sites based on a randomized complete block design with non-irrigated and irrigated plots constituting the main experimental blocks. The treatments showed significant (P ≤ 0.05) variations in the susceptibility of varieties to crop and tuber pests and diseases in respective seasons, sites and time intervals. No single variety exhibited complete tolerance to aphid infestation under either soil moisture regimes. In contrast, Desiree and Royal varieties exhibited significantly higher tolerance to beetles and whiteflies in seasons one and two, respectively (P ≤ 0.05). Mayan Gold was the only variety that recorded significant tolerance to early and late blight. Similarly, no single variety exhibited susceptibility or tolerance to tuber diseases and pests across treatments, sites and seasons. Correlation analysis revealed significant relationships among and between pests, diseases and yield. A significant and strong positive correlation was observed between whitefly presence, diseased tubers, and yield across treatments (P ≤ 0.05). Overall, cultivar susceptibility to insect pests and diseases varied significantly, with no single variety demonstrating consistent resistance. These findings underscore the importance of considering both soil moisture availability and local agroecological conditions when selecting potato varieties for pest and disease management. For farmers and researchers, integrating water management with site-specific varietal selection offers a practical pathway to improve resilience and productivity in potato farming systems under climate stress.

Root maggots pose a growing global threat to food security, causing potential crop losses of up to 100 %, prompting the search for innovative and sustainable management strategies. In this review, we examine the global distribution of root maggots, evaluate the current management strategies and their effectiveness, and explore the potential of insect frass fertilizer as a novel, cost-effective, and multipurpose soil amendment for root maggot control. We report a wide distribution of Delia species in over 123 countries globally, with geographical specific distribution of individual species. Species such as D. radicum, D. planipalpis, D. floralis and D. antiqua strictly occur in Palaearctic and Nearctic regions whereas D. steiniella, D. flavibasis, D. arambuorgi and D. coarctata were restricted to the tropical climate of Sub-Saharan Africa. Notably, D. platura was the most widely distributed species, occurring across all bioregions. Furthermore, crop damage and yield loss were strongly influenced by factors such as soil type, climatic conditions, crop variety, cropping season, and the management approach. Despite recent advancements in integrated pest management, farmers still favour pesticides, which does not provide any advantage for long-term pest control. We present insect frass fertilizer as a promising alternative strategy for managing root maggots by inducing systemic resistance in plants, enhancing natural enemy populations, and exerting direct contacticidal effects. This information is essential for fostering cross-disciplinary collaboration among farmers, researchers, and policymakers, forming the basis for sustainable root maggot control, improved food security, and enhanced ecosystem resilience.

Maize is prone to aflatoxin contamination prevailing in the high-risk regions in Kenya, where maize is rendered unfit for uses as food and feed. The objective of the study was to identify strategies that can be used to decontaminate aflatoxin in contaminated maize. Therefore, an experiment was conducted using maize from Kilifi contaminated with aflatoxin soaked in different solutions, done as single and combined treatments. Maize grains were used in portions of 250 g for the mitigation experiments and placed in conical flasks of 1 litre capacity and treatment application done. All the treatments were compared to the control with no treatment applied and set to 100%. The results revealed that, aflatoxin was reduced by 78.9% by soaking maize kernels in distilled water for 24 h under a single treatment. Soaking in aqueous ammonia for 24 h reduced aflatoxin by 68.1%. Soaking grains in sodium bisulphite for 24 h reduced by 59.3% and citric acid by 38.8%. The combination of sorting and aqueous ammonia was most effective with 90.8% aflatoxin reduction. The combination of sorting and sodium bisulphite lowered the levels to 72.9%, while citric acid and dehulling were 55.3% effective. Aflatoxin reduction methods to levels that are within the allowable limits of 10 mu g/kg and 20 mu g/kg will enable grains to be used as human food and livestock feed, respectively. Therefore, effective methods should be adopted by farmers to put maize to good use for human food and livestock feed instead of throwing away or using it with the high levels of aflatoxin.

Several measures have been recommended in the control of potato cyst nematodes (PCN) with resistant potato cultivars being considered as the most practical and affordable for smallholder potato farmers in Kenya. However, the level of resistance in locally grown potato varieties is yet to be established. The aim of this study was to screen Kenyan potato cultivars against PCN under greenhouse conditions. Eleven potato cultivars namely Shangi, Dutch Robijn, Sherekea, Nyota, Roseline tana, Tigoni, Unica, Asante, Chulu, Kenya Mpya and Arka were screened with Desiree (susceptible variety), Manitou (resistant cultivar) as controls. For each potato cultivar, there were two sets of plants with the first set being inoculated with 50 cysts, while the second batch was nematode-free. The treatments were arranged in a completely randomized design with three replications. A scale of 1-9, with 9 indicating the highest level of resistance was used in the assessment of disease severity. Nematode infestation caused a reduction in root mass across the 11 cultivars from 20 to 100% compared to uninoculated controls. Reproductive index of PCN viable eggs across the 11 cultivars was <1 compared to control (Desiree). Potato cultivars Shangi, Tigoni, Dutch, Chulu, Asante, Unica, Arka, Kenya Mpya, and Roseline Tana had a severity score of 1-3 (>95%), hence were considered to be susceptible to PCN. The cultivars Sherekea and Nyota had a severity score of 4-6 (<25%) and hence were considered partially resistant to PCN. The findings of this study provides a basis of integrating partially resistant potato cultivars into PCN management in smallholder farms. Keywords: Cyst viable eggs, reproductive index, resistance, susceptible, smallholder farmers, severity score.

Aflatoxin levels increase during storage due to high humidity, temperature, and insect pests. The study determined the effectiveness of three levels of natural products in controlling aflatoxins at storage, done in 2023 at Kalro Njoro in Kenya. Maize grains were collected from Kilifi and weighed to 1 kg each and placed in polypropylene bags. Three levels of Moringa oleifera powder (10g/kg, 20g/kg and 30g/kg) from young moringa leaves, wood ash at (5g/kg, 7.5g/kg and 10g/kg) from Eucalyptus globulus from a dried log of wood from Eucalyptus globulus and diatomaceous earth (1g/kg, 2g/kg and 3g/kg) and a control (no treatment) were used. A completely randomized design replicated three times was used. Grains were stored for three and six months and total aflatoxin quantification was performed using ELISA. At six months aflatoxins levels had increased up to ten times from the three months storage. In the sixth month the total aflatoxins levels were 0.84 mu g/kg for wood ash at 7.5 g/kg of maize with the lowest levels. The wood ash at all three levels reduced aflatoxins effectively. Additionally, for both diatomaceous earth and Moringa oleifera powder at low and medium levels were effective. These natural products should be used during storage because they reduce aflatoxins and not harmful to humans and animals.

Coffee is an important commodity for Kenya, where production is steadily declining, despite a global rise in demand. Of the various constraints affecting production, plant-parasitic nematodes are a significant, but often overlooked, threat. As a perennial crop, treating plantations once infected with nematodes becomes difficult. The current study evaluated the drenching application of two biocontrol agents, Trichoderma asperellum and Purpureocillium lilacinum, for their nematode control efficacy, as well as their impact on the soil nematode community structure on mature, established coffee trees in Kenya. Seven Arabica coffee field trials were conducted over two years on trees of various ages. All the fields were heavily infested with Meloidogyne hapla, the first report of the species on coffee in Kenya. Both fungal biocontrol agents were detected endophytically infecting roots and recovered from soil but not until six months after initial applications. The population densities of M. hapla had significantly declined in roots of treated trees 12 months after the initial application, although soil nematode density data were similar across treatments. Based upon the maturity index and the Shannon index, treatment with T. asperellum led to improved soil health conditions and enrichment of diversity in the microbial community. Application of P. lilacinum, in particular, led to an increased abundance of fungivorous nematodes, especially Aphelenchus spp., for which P. lilacinum would appear to be a preferred food source. The soils in the trials were all stressed and denuded, however, which likely delayed the impact of such treatments or detection of any differences between treatments using indices, such as the functional metabolic footprint, over the period of study. A longer period of study would therefore likely provide a better indication of treatment benefits. The current study positively demonstrates, however, the potential for using biologically based options for the environmentally and climate-smart management of nematode threats in a sustainable manner on established, mature coffee plantations.

In Africa, banana is mainly produced by smallscale farmers under complex production systems for both home consumption and income generation. Low soil fertility continually constraints its production and farmers are embarking on emerging technologies such as improved fallow, cover crops, integrated soil fertility management, agroforestry with fast growing tree species to address this challenge. This study aims at assessing the sustainability of grevillea-banana agroforestry systems by investigating the variability in their soil physico-chemical properties. Soil samples were collected in banana sole stands, Grevillea robusta sole stands and grevillea-banana intercrops in three agro-ecological zones during the dry and rainy seasons. Soil physico-chemical properties significantly differed among agroecological zones, cropping systems and between seasons. Soil moisture, total organic carbon (TOC), P, N, Mg decreased from the highland to the lowland zone, through the midland zone whereas soil pH, K and Ca showed the opposite trend. Soil bulk density, moisture, TOC, NH4+-N, K and Mg were significantly higher in the dry season compared to the rainy season but total N was higher in the rainy season. Intercropping banana with grevillea trees significantly decreased soil bulk density, TOC, K, Mg, Ca and P. Soils under banana sole stands accumulated higher potassium, magnesium, calcium, phosphorus with a higher soil bulk density and pH compared to grevillea-banana intercrops and grevillea sole stands. This suggests that intercropping banana and grevillea trees increases the competition for these nutrients and requires careful attention for the optimization of their interactive benefits.

Cabbage and Onion production in sub-Saharan Africa face numerous pest constraints that needs to be overcome to feed the rapidly growing population. This study aimed to establish the occurrence, incidence, and severity of soil-dwelling pests of cabbage and onions, and current management practices in five Counties of Kenya. Our findings revealed that most farmers grew hybrid vegetables on a small scale, which were highly dominated by various pest species (Delia platura, Maladera sp., and Agriotes sp. for cabbage and Atherigona orientalis and Urophorus humeralis for onion. The occurrence, incidence and severity of the various pest species on both crops varied considerably. Over 95% of the farmers relied on synthetic insecticides, which were applied weekly or bimonthly with limited success. Our findings demonstrate that invasive and polyphagous A. orientalis and D. platura were the most devastating pests of onion and cabbage without effective control options. Therefore, effective, sustainable, and affordable management strategies are required to control the spread of these pests to other crops in the region.

Abstract. In-vitro assays to determine the effect of plant extracts on egg viability and mortality of J2s of potato cyst nematode were evaluated. Methanol, ethyl acetate, hexane and water were used as solvents. Eggs and J2s were exposed to plant extracts for 24, 48 and 72 hrs. Treatments were arranged in a completely randomized design with three replications. Loss of egg viability and mortality of J2s significantly increased with an increase in the time of exposure to the extracts. Hexane extracts had a significantly higher loss of egg viability. Mexican sunflower extracts had a significantly higher loss of egg viability, having 93 and 89.2% non-viable eggs/cyst in experiments 1 and 2, respectively, compared to other plant extracts. This was followed by garlic, which had 89.5 % and 86.3%, and then ginger, 86.8% and 85.9% non-viable eggs/cyst in experiments 1 and 2, respectively. Garlic, Mexican sunflower and ginger after 72 hrs of treatment exposure had significantly (P<0.05) high juvenile mortalities of 64.5%, 64.9% and 70.2%. Mexican sunflower, ginger and garlic extracts were effective in inducing loss of egg viability and mortality of J2s of PCN.

Tylosemafassoglense (Fabaceae) is a tuber producing vine, endemic to sub-Saharan Africa, where it's used as food, fodder and medicine. However, its domestication may be hampered by limited information on its seed dormancy and germination ecology. This study evaluated seed-coat dormancy on three seed lots, collected from Busia, Migori and Siaya counties in Kenya, and the role of light on germination. Seed-coat dormancy was studied by water imbibition and germination percentage at 25℃ on scarified and non-scarified seeds from each seed lot.

The study aimed to verify the effectiveness of two detection kits namely, Accuscan gold reader and RIDA total aflatoxin smart phone application in assessing levels of aflatoxins’ contamination in maize. Three regions of Kenya were selected namely, Kisumu, Makueni and Kilifi. Confirmatory tests were done using liquid chromatography tandem mass spectrometry (LC-MS/MS). The Accuscan gold reader showed mean aflatoxin levels of 14.52, 5.18, and 3.04 μg/kg and RIDA smart phone application had levels of 26.08, 26.68, and 4.05 μg/kg for Kilifi, Makueni, and Kisumu, respectively. The LC-MS/MS confirmed the presence of AFB1 and AFB2 with AFB1 of 97.5 μg/kg in Makueni and 76.2 μg/kg in Kilifi. Maize from Kilifi and Makueni was contaminated and unfit for human and animal consumption. Also, low rainfall, high temperature and high relative humidity directly increased the levels of aflatoxins, resulting in contamination. Therefore, the detection kits are recommended for use by maize farmers. Confirmatory tests should be done with maize having levels of aflatoxin above 10 μg/kg. Adequate drying and handling of maize and proper storage with good aeration should be ensured.

Abstract This chapter focuses on the economic importance, damage symptoms, cumulative damage impact and some recommended integrated nematode management programmes of plant parasitic nematodes in smallholder maize cropping systems in East Africa. Information on the various improvements in the current nematode management methods and recommendations for future research are also discussed.

Banana categorized as third in world’s key starch crops after cassava and sweet potatoes and it is the fourth most widely grown crop after rice, wheat and maize. The crop accounts for over 70 % of farmer’s earnings in Kisii county of Kenya. Farmers growing the crop are facing several challenges including depletion of soil fertility, low yields and diseases especially Fusarium wilt caused by Fusarium oxysporum f.sp. cubense (Foc). A study was conducted to determine the status of this disease in Kisii County. Ten farms were sampled in each Agro-ecological zone and in each farm four symptomatic and four non-symptomatic mats were sampled. Incidence was determined by relating banana seedlings affected and the total number of banana seedlings planted while severity was determined by measuring the extent of the damage/brown discoloration of the stem in length. Banana roots and pseudostem cuttings that were infected with the disease were used for isolation of the pathogen.Fusarium wilt is common in banana producing regions of Kisii County, however, the management practices are poor and do not meet the required strategies for controlling the disease. It was established that only; wood-ash and poultry manure were used by a few farmers in managing this disease. Present report is an attempt to improve the understanding of distribution and diversity of Foc in banana producing regions of Kisii County thereby aiding formulation of appropriate mitigation measures which the farmers can adopt locally.

Determining if the vast soil health degradations across the seven major soil groups (orders) of Sub-Saharan Africa (SSA) can be managed on the basis of a one-size-fits-all or location-specific approach is limited by a lack of soil group-based understanding of soil health degradations. We used the relationship between changes in nematode population dynamics relative to food and reproduction (enrichment, EI) and resistance to disturbance (structure, SI) indices to characterize the soil food web (SFW) and soil health conditions of Ferralsol, Lithosol and Nitosol soil groups in Ghana, Kenya and Malawi. We applied bivariate correlations of EI, SI, soil pH, soil organic carbon (SOC), and texture (sand, silt and clay) to identify integrated indicator parameters, and principal component analysis (PCA) to determine how all measured parameters, soil groups, and countries align. A total of 512 georeferenced soil samples from disturbed (agricultural) and undisturbed (natural vegetation) landscapes were analyzed. Nematode trophic group abundance was low and varied by soil group, landscape and country. The resource-limited and degraded SFW conditions separated by soil groups and by country. EI and SI correlation with SOC varied by landscape, soil group or country. PCA alignment showed separation of soil groups within and across countries. The study developed the first biophysicochemical proof-of-concept that the soil groups need to be treated separately when formulating scalable soil health management strategies in SSA.

Accurate diagnosis is a prerequisite to effective management of plant diseases especially those whose symptoms are not very specific. A survey was conducted from February to March 2018 to detect the presence and determine the distribution of six viruses infecting pepper in Rwanda. A total of 225 symptomatic samples were collected from high, mid and low-altitude zones, and analysed using serology assay with antibodies to cucumber mosaic virus (CMV), potato virus Y (PVY), pepper veinal mottle virus (PVMV), pepper mild mottle virus (PMMoV) and tobacco mosaic virus (TMV). Polymerase chain reaction was used to confirm the results from serology and to test for the presence of pepper vein yellows virus (PeVYV), which has no commercial antibodies. Amplified DNA fragments were sequenced and compared with other known pepper viruses available in the GenBank database. Seventy-three percent of the samples tested positive for at least one of the viruses. CMV, PVY, PVMV, TMV and PMMoV were detected in all zones but PeVYV was detected in the mid and low-altitude areas. CMV was the most widespread and was detected in 48% of the samples, followed by PVMV and PVY in 23.6% and 18.2%, respectively. There were both single (36%) and mixed (34.6%) infections of the viruses. Sequence and phylogenetic analysis confirmed the presence of CMV, PeVYV, PVMV and TMV in the country. This is the first report of TMV, PMMoV and PVY infecting pepper in Rwanda. Efforts towards the development of sustainable management for these viruses should be put in place to improve yields and quality of hot pepper.

Potato pest and disease management has been dominated by chemical pesticides, despite their potential undesirable effects on the environment, food safety and human health. This study explores factors influencing intensity of uptake of alternative pest management practices among potato farmers in Kenya, through a survey of 1,002 farmers in six main potato growing counties in the country. A Poisson count model was used to determine the intensity of uptake of alternative pest management practices. On average, farmers employed five practices: weeding, fertilizer application, recommended spacing, scouting, and crop rotation. Age of respondent (older farmers) and utilization of face-to-face and participatory extension approaches were significantly and positively associated with intensity of uptake of alternative pest control practices. Passive sources of extension advice such as radio and television were inversely related to uptake intensity of alternative pest control practices. These findings underscore the efficacy of agricultural information sources that are practical in approach, as they have the greatest potential to influence farmers’ adoption decisions. Mass communication methods create awareness and provide information at low-cost, but are not sufficient in triggering behaviour change when used on their own. There is therefore need to integrate them with conventional extension approaches to achieve the duo benefit of scale and adoption. Keywords: Potato, Alternative pest management practices, Poisson count model, Kenya.

The quality and shelf life of French beans is affected by the time of harvesting and storage period. Cooling immediately after harvesting is important. The use of a solar evaporative cooling system is suitable for use in rural areas with no power grid connections. This study compared evaporative charcoal cooler and solar cooling systems on improving the quality and shelf life of French beans. The prototype was made using mathematical modeling equations and was powered by solar power while the evaporative charcoal cooler was made from iron sheets with charcoal walls. Freshly harvested French beans were stored under the two cooling systems. The weight and temperature of the stored produce were checked hourly. At the end of the day, produce was packed into modified atmosphere packaging (MAP) bags and stored for 7 days in a cold room. After seven days, oxygen and carbon dioxide levels were measured using a Bridge gas analyzer. The results show significant differences in weight loss between produce stored in evaporative charcoal shed and solar cooler prototype with those stored in evaporative charcoal cooler having 5% weight reduction while those solar coolers having 3% weight loss. A higher accumulation of CO2 was realized in the evaporative charcoal cooler than in the solar-powered cooler. The solar-powered cooler maintained weight, reduced the temperature of products, and maintained the balance between carbon dioxide and oxygen thus reduction in metabolic activities. This enhanced the shelf life and quality of the produce.

Aphids are associated with loss in yield and quality of pepper crop due to damage they cause and the transmission of viruses in a non-persistent manner. The aim of the study was to determine the potential of border crops and intercrops in the management of aphids and the associated viruses in hot pepper production. Field experiments were carried out for two seasons in 2018/2019 at Rubona Research station, Huye District, Rwanda. Maize (Zea Mays L.), sorghum (Sorghum bicolor L.) and sunflower (Helianthus annuus) were tested as companion crops associated with hot pepper either as border crops or as intercrops. Randomized complete block design was used with four treatments and three replications per experiment. Data on aphid population, the virus disease incidence, the area under the disease progress curve (AUDPC), growth and yield of hot pepper were recorded. Diseased leaf samples were collected and analysed serologically to detect the viruses present in the experimental plots. Aphid-transmitted viruses; Cucumber mosaic virus, Potato virus Y and Pepper veinal mottle virus, and aphid species, namely Aphis gossypii and Macrosiphum euphorbiae were identified in the experimental plots. The use of maize, sorghum or sunflower as border crops or as intercrops significantly reduced (p < 0.05) the incidence of viral diseases in hot pepper compared with control at later stages of growth. At 12 weeks after transplanting (WAP), use of maize, sunflower or sorghum as border crops significantly reduced (p < 0.05) the incidence of viral diseases by 24%, 31% and 38% compared with the control in season one and by 32%, 54% and 46% in season two. Similarly, intercropping with maize, sunflower or sorghum was also effective in reducing incidence of viral diseases in hot pepper by 24%, 35% and 27% in season one, and by 39%, 39% and 32% in season two, respectively. The AUDPC differed significantly (p 0.05) while the population of aphids did not differ (p 0.05) among treatments for both experiments. Results revealed that maize, sorghum and sunflower can be utilized either as border crops or intercrops for the control of viral diseases in pepper production. This technology is environmentally friendly, easily adaptable and appropriate since the production of pepper is mainly done by resource-poor farmers.

Hot pepper (Capsicum spp.) is an important cash crop in Rwanda however, its productivity can only increase after addressing factors that limit its production. This study aimed at revealing the farmers’ knowledge and perceptions of virus diseases and their management in Rwanda. A survey was conducted between February and March 2018 in the main hot pepper growing areas covering low, mid and high-altitude agro-ecological zones (AEZs). Household data were collected using a structured questionnaire from 101 respondents and analysed using descriptive statistics. Majority of farmers (86.1%) indicated that pests and diseases were the main constraints to hot pepper production. Viral diseases were perceived by 71.9% of the farmers as the most serious diseases while 51.4% and 12.9% of them reported that aphids and whiteflies were the major insect pests of hot pepper, respectively. Only 17.8% and 25.7% of the farmers attributed the cause of the viral diseases to insect vectors and the use of infected seeds, respectively. The main method used to control viral diseases was application of synthetic pesticides. About two-thirds of the farmers lacked in knowledge of viral disease symptoms, spread and management across all AEZs. Majority of the farmers (80.2%) did not have access to extension service or training but relied mainly on farmer-interactions for information. Therefore, interventions such as farm-level training to raise the farmers’ awareness of diseases, especially viral diseases and integrated disease management are needed. This study provides baseline information for the development of sustainable integrated pest management (IPM) strategy for hot pepper viral diseases in Rwanda. [Fundam Appl Agric 2020; 5(3.000): 319-329]