Identification of novel source and inheritance of resistance to bacterial wilt (Ralstonia solanacearum) in tomato (Solanum lycopersicum L.) for sustainable disease management

Current status and determinants of tomato Fusarium wilt ( Fusarium oxysporum f. sp. lycopersici ) epidemics under high-tunnel production system in northwest Ethiopia

Background : High-tunnel tomato cultivation technology is vital for year-round production during the rainy season and for enhancing income among smallholder farmers in north-west Ethiopia. However, its productivity and sustainability are adversely affected by Fusarium wilt (FW) disease. This study assessed the current status of FW epidemics, examined associated biophysical factors, and characterized Fusarium oxysporum f. sp. lycopersici (FOL) isolates during the 2024 main cropping season. Methods : A total of 75 high-tunnel technologies were inspected in four major tomato-producing districts within two zones. A logistic regression model was used to associate biophysical factors with disease incidence and severity. Results : All the surveyed high-tunnels were infected with FW, with incidence ranging from 43.6% (Libo Kemkem) to 60.5% (Dera), and severity from 41.4% to 58.3%. Disease incidence and severity were strongly correlated (P < 0.001) with district, age and leakiness of high-tunnels, seed type and source, plant and weed density, crop rotation, and irrigation method. Elevated incidence and severity (>50%) were notably associated with Dera district, gray soils, older and leaky high-tunnels, local and unknown seed varieties, informal seed exchange, high plant and weed density, fruit-setting stage, absence of crop rotation, and contact irrigation method. Pathogen isolation and characterization study identified eight morpho-culturally and pathogenically diverse FOL isolates. Conclusion : FW exhibits extensive distribution across high-tunnel technologies, driven by various biophysical factors and has diverse strains. Therefore, integrated management strategies, including cultural interventions and resistant varieties, are imperative for sustainable high-tunnel tomato production in the study area. Further research on temporal pathogen dynamics and molecular characterization of isolates is also recommended.

Screening of Chickpea Genotypes for Fusarium Wilt ( Fusarium oxysporum ) Resistance Under Field Condition in West Hararghe, Oromia

Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceris, is a major constraint to chickpea production worldwide, resulting in substantial yield reduction and deterioration of crop quality. The effectiveness of host resistance is often challenged by the emergence of new pathogen races, necessitating the continuous identification of resistant germplasm for breeding programs. This study was conducted to identify chickpea genotypes with resistance to Fusarium wilt and to select promising materials for further breeding. A total of 47 chickpea genotypes, along with two standard checks (Geletu and Dimtu), were evaluated under field conditions during the 2022 and 2023 main cropping seasons using an augmented experimental design. Disease incidence was recorded at both seedling and flowering stages, and genotypes were classified according to the ICRISAT disease rating scale. Considerable variation in disease response was observed among the tested genotypes. Two genotypes exhibited resistant reactions, while seventeen were categorized as moderately resistant. Overall, nineteen genotypes demonstrated desirable levels of resistance and were identified as valuable sources of resistance for future chickpea improvement programs. These genotypes can be advanced to subsequent breeding stages for the development of Fusarium wilt-resistant chickpea varieties.

Integrating host resistance and botanical agents: Screening pigeonpea [Cajanus cajan (L.) Huth] genotypes for Fusarium wilt (Fusarium udum Butler) management

Fusarium wilt, caused by Fusarium udum Butler, is a major biotic constraint limiting pigeonpea (Cajanus cajan L. Huth) productivity in tropical and subtropical regions. Wilt incidence varied widely among 143 pigeonpea genotypes, ranging from 0.40 to 15.60 % at 30 days after sowing and escalating to 2.00 to 78.00  % at 75 DAS. Area under disease progress curve (AUDPC) values ranged from 57.9 to 2258.1, indicating diverse disease progression. Based on the percent disease index (PDI), relative AUDPC (rAUDPC) and r-values, genotypes were categorised as resistant (38.5 %), moderately resistant (37.8 %), susceptible (11.9 %) and highly susceptible (11.9 %). Notable resistant genotypes included Pusa Arhar 21-60, ICP 8863 and NAM 88. In vitro evaluation of seven plant extracts at 10, 15 and 20 ppm using the poisoned food technique revealed significant variation in antifungal activity. Thuja occidentalis L., Cannabis sativa L. and Mentha spicata L. consistently exhibited the highest inhibition in a dose-dependent manner, whereas Chenopodium album L. was least effective. Integration of resistant genotypes with potent botanical extracts offers an eco-friendly strategy for sustainable management of Fusarium wilt in pigeonpea.

Prevalence and Incidence of Major Fungal Diseases of Tomato (Solanum Lycopersicum L) In Kano and Kaduna States, Northern Nigeria

Tomato (Solanum lycopersicum L.) is a major cash crop in Northern Nigeria, but fungal diseases are widely cited as a principal cause of the persistent gap between smallholder and research-station yields (Mohammed et al., 2023; Usman & Mohammed, 2023). Standardised, farm-level epidemiological data comparing disease burden between contrasting agroecological zones remain scarce. This study determined the prevalence and incidence of five major tomato fungal diseases across eight Local Government Areas (LGAs) in Kano and Kaduna States and compared disease burden descriptively between the two states. A total of 240 tomato farms (30 per LGA) were monitored biweekly over two consecutive growing seasons using standardised photographic field guides and pathologist-verified identification protocols (inter-rater κ ≥ 0.80). Early blight was the most prevalent disease overall, recorded on 86.7% of farms in Kano State and 79.3% in Kaduna State. Because between-state comparisons necessarily used LGA-level means (n = 4 per state) as the unit of analysis to avoid pseudo-replication across clustered farms, these comparisons are reported as descriptive, ecological-level patterns rather than confirmatory population-level tests: Kano State showed a consistently higher late blight burden (74.3% vs. 61.7% prevalence, 95% CI for the difference [9.7, 15.5]) while Kaduna State showed a consistently higher Fusarium wilt burden (73.3% vs. 57.7% prevalence, 95% CI for the difference [-18.7, -12.6]), patterns consistent with the irrigated-lowland versus cooler continuous-monoculture profiles of the two states. Baseline farmer disease-identification accuracy was only 41.0%, confirming that unaided visual diagnosis is insufficient to guide fungicide decisions (Balogun et al., 2023; Yakubu et al., 2024). These findings provide a standardised between-state epidemiological comparison for two leading tomato-producing states and support state-differentiated disease management guidance rather than uniform national recommendations, though confirmatory farm-level modelling is recommended before the between-state differences are treated as definitive.

Screening of chilli (Capsicum annuum L.) germplasm for resistance to broad mite, Polyphagotarsonemus latus (Banks) under field conditions

Chilli (Capsicum annuum L.) is an economically important spice and vegetable crop cultivated extensively in tropical and subtropical regions of the world. However, its productivity is severely constrained by several insect and mite pests, among which the broad mite, Polyphagotarsonemus latus (Banks), is a major pest causing leaf curling, stunted growth, flower drop and substantial yield losses. Developing resistant cultivars offers an eco-friendly and sustainable approach for broad mite management. Therefore, field investigations were conducted during kharif 2023 and 2024 to evaluate sixteen chilli genotypes, including the susceptible check Byadgi Dabbi, for resistance against broad mite infestation. The study aimed to assess genotypic variability and identify resistant sources for future breeding programmes. During 2023, mean mite infestation was 2.96 mites per leaf, ranging from 2.30–4.02 mites per leaf. Higher populations were recorded on Sadabahar, Rasgulla and Byadgi Kaddi, whereas Phule Jyoti and Phule Mukta exhibited lower infestation levels. Mite incidence commenced at 45 days after transplanting (DAT), reached its peak at 120 DAT and declined thereafter. In 2024, infestation ranged from 1.98–3.78 mites per leaf, with maximum incidence observed at 90 DAT. Sadabahar remained highly susceptible, while Phule Jyoti, RHRCH 8-2 and Phule Mukta consistently recorded lower mite populations. The pooled mean infestation was 2.79 mites per leaf (2.14–3.90). Based on resistance categorisation, 2 genotypes were identified as resistant, 8 as moderately resistant, 3 as moderately susceptible and 3 as susceptible, indicating substantial genetic variability and providing valuable sources for resistance breeding and integrated pest management programmes in chilli.

Plant growth promotion of rice (Oryza sativa L.) with root endophytic bacteria, isolated from wild Solanaceous medicinal plants Solanum nigrum L., Solanum sisymbriifolium Lam., and Solanum virginianum L.