Zimbabwe is an economy based on agriculture, which has a very high contribution to the gross domestic product (GDP) (Runganga & Mhaka 2021), contributing 15% – 18% GDP (Chung et al. 2010). African countries have abundant natural resources and labour, which can be manipulated for the reduction of poverty and inequality and achieving inclusive growth by enhancing labour-intensive agricultural production (Mhaka & Runganga 2023). Since 2000, with the advent of the Fast Track Land Reform programme (Comprehensive Agricultural Policy Framework, 2012–2032; Shonhe 2019).

Zimbabwe’s agrarian structure showed new production and commoditisation patterns across settlement types, where new markets were established with differentiated effects on capital accumulation for different sets of farmers (Shonhe 2019). The growing importance of Cleome gynandra calls for a thorough assessment of the pathogen spectrum that affects the plant and making recommendations for pathogen control and disease management, as the crop is recommended for commercial crop production. The inclusion of C. gynandra into the crop mainstream will see it contributing much to the agriculture industry by boosting the African indigenous vegetable market as it has been on high demand. Mativavarira et al. (2024) conducted research using some of the C. gynandra landraces on breeding priorities and preferences of the landraces in Zimbabwe, which were used in this research. There is a need to identify pathogens and their effects on different accessions of C. gynandra, to make conclusions on a wide range of accessions to reduce the gap of leaving other pathogens unidentified. Quality and control of agricultural produce require accurate estimates of disease incidence, severity and negative effects of diseases on field crops, horticulture, plant breeding, for improving fungicide efficacy and for plant research. Qualitative and quantitative effects on the extent of disease can be as a result of genetic variation (Chung et al. 2010). Pathogenesis is the series of events that occur in a host–pathogen interaction, including infection and colonisation of the host, as well as reproduction and dissemination of the pathogen (Chung et al. 2010). Survival and perpetuation of fungal diseases in different environments are determined by their pathogenic potential, which is attributed to genetic factors conditioned by their surrounding environment (Narayanasamy 2011). Time frame for control action is hampered by the appearance and sudden spread of disease on a large scale in a greenhouse, leaving little or no time for a farmer to take control actions (Troncoso-Rojas & Tiznado-Hernández 2014). Environmental conditions were observed by Araujo et al. (2016) to have influenced the aggressiveness of the fungus of the genus Colletotrichum, with most symptoms observed in the second phase of data collection.

Diseases reduce plant productivity and eventual yields (Agrios 2004). The susceptibility of plant hosts depends on the cultivars.

It was discovered that specific cultivars of tomato (Lycopersicon esculentum Mill.) are susceptible to a stem canker disease caused by Alternaria alternata, though it is known to cause disease in a wide range of plant hosts. Albugo species require high moisture and temperature conditions for rapid infestation and growth. Albugo species causes white rust in different plants (MacDonald & Punja 2018; Narayanasamy 2011; Troncoso-Rojas & Tiznado-Hernández 2014). The Fusarium genus has many species that are pathogenic to plants, being a soil-borne necrotrophic pathogen (Agrios 2004). Genetic variability in plants affects the production of phytochemicals (Narayanasamy 2011; Ogwu, Izah & Joshua 2025).

In a research that was conducted to investigate phytochemical content and genetic diversity of five Asparagaceae plant species, it was noted that there was significant variability in quantities among species (Mohamad-Rosdi, Awang & Abu Bakar 2025). Plants have essential oils that include terpenes, phenolics and aldehydes that target multiple fungal cellular sites interfering with cellular activities, resulting in cell death (Dantas et al. 2025; Jimenez-Reyes et al. 2019; Leiva-Mora et al. 2025). These essential oils are called phytochemicals and are effective to manage plant diseases caused by phytopathogenic fungi (Dantas et al. 2025; Deresa & Diriba 2023). Cleome gynandra extracts have been identified to contain phenolics, flavonoids (Behera et al. 2024; Meda et al. 2013), condensed tannins (Kutsukutsa et al. 2014; Mohamad-Rosdi et al. 2025) saponins, alkaloids, cardiac glycosides, terpanoids (Torres et al. 2017) in their extracts, and these have been identified to be responsible for antifungal activities of phytopathogenic fungi (Dantas et al. 2025; Deresa & Diriba 2023; Mohamad-Rosdi et al. 2025).

Phytochemical profiles differ because of environmental influence, where warmer climates promote higher production than cooler climates. Soil composition, nutrient availability and environmental stressors also contribute to differences in phytochemical composition in plants (Eamon 2023).

In a survey conducted in four provinces of Zimbabwe on diseases affecting C. gynandra, nine pathogens were isolated. The research aimed to further assess the pathogens on their effects on four different accessions of C. gynandra to ascertain their pathogenicity and disease severity, so as to establish the extent of damage the pathogens can have on different accessions before commercial production of C. gynandra commences.

Mutare Mutanda area had F. chlamydosporum, Albugo laibachii, Marondera, MUAST AIP area had Fusarium verticillioides, F. chlamydosporum, A. laibachii with red pustules and the other one with green pustules, A. alternata and F. equiseti, Masvingo, Zimuto area had both A. laibachi with red pustules and the one with green pustules, Sarocladium striticum, Cladosporium pseudocladosporioides and Mutare, Premier area had F. equiseti, Fusarium oxysporum, A. laibachii with green pustules, A. alternata, A. senecionicola, isolates that were all evaluated against the four accessions. In this study, the pathogenicity of isolated pathogens was assessed on four accessions of C. gynandra in a greenhouse.

As shown in Table 2 and Table 3, accessions significantly responded differently for both AUDPCs and disease incidence to the isolates (p = 0.02 and p = 0.009, respectively). There were interactive effects between accessions and isolates for AUDPCs (p < 0.001) (Figure 1). There were interactive effects between accessions and isolates for disease incidences (p < 0.001) (Figure 2). Data from this study revealed marked differences in pathogenicity of isolates throughout the experimental period on the accessions. Accession 4 (CG KENYA), which originated from the Republic of Kenya, showed high susceptibility. Thus, the highest AUDPCs were observed against Accession 3 (CGMRGP-Marondera), Marondera, Zimbabwe, Accession 1 (CGZIM) from Chipinge, Zimbabwe and Accession 2 (CGGUR) from Masvingo, Zimbabwe.

Among the interactions between accessions and isolates on Accession 1 (purple green stems), there were only three isolates out of 18 that had disease severity scores below 50% on week 5–6 with F. verticilliodes isolate from Marondera, MUAST AIP area and C. pseudocladosporioides isolate from Masvingo, Zimuto area, which had no disease severity being recorded for the 42 days’ period, and A. laibachii isolate from Masvingo, Zimuto area, had severity scores below 40% for the 42-day evaluation period. The rest of the isolates had disease severity scores going up to above 50%, though starting with low severity scores being below 20% for week 1–2, giving a chance of disease management if control measures are applied, and the diseases will be controlled and have healthy plants. The severity scores were rising to above 60%, with most being 80% and 100% AUDPCs for the last days of evaluation, days 35–42. Interactions between Accession 2 (Green stems) and the isolates had shown that five out of 18 isolates had AUDPC evaluations below 50% of disease severity scores, where the F. equiseti isolate from Marondera, MUAST AIP area had no severity recorded for the 42-day period. Cladosporium pseudocladosporioides had an AUDPC of 7.2 on day 7–14, and it increased to 7.7 below 50%. Two of the A. laibachii isolates from the Masvingo Zimuto area, one with red pustules and the other with green pustules, and the Mutare, Mutanda 2 area had severity of 7.3 on day 7–14 and increased to 7.4 and 7.3, respectively, which are below 20%. Albugo laibachii with green pustules had an AUDPC of 7.7, which is below 50%. The rest of the isolates initially had low severity scores below 20% and increased from day 7 to 14 to the last days of evaluation with ADUDPCs ranging from 8 to 8.2, which is 80% – 100% severity scores. Evaluations done showed that interactions between Accession 3 (Purple stems) were noted on two isolates, with disease severity scores and AUDPC values below 50%. It had two isolates that had low AUDPCs with F. oxysporum from the Mutare Premier area, having 7.2 AUDPC, which is below 20% and increased to 7.4, still below 20%. Albugo laibachii isolate from Marondera MUAST AIP had an initial AUDPC for days 7–14 of 7.5, increasing to 7.6 AUDPC during the period week 5–6, which is below 40%.

The rest of the isolates had AUDPCs for day 7–14, being 7.7, which are below 50% except for A. alternate isolate from Marondera, MUAST AIP, which had a higher AUDPC of 7.8–8.2 during the evaluation period. Accession 4 (Deep purple stems) had only one isolate out of 18 A. laibachii from Marondera, MUAST AIP, with AUDPC ranging from 7.2 (day 7–14) to 7.6 (day 35–42), which were below 40%. The remaining isolates had AUDPCs ranging from 7.1 to 7.9, with 8.2 being the highest AUDPC for the disease severity scores.

Observations made with the same species isolated from different areas, which exhibited so many differences in AUDPC values, may be attributed to changes in environmental conditions because of differences in geographical distribution, as discussed in Agrios (2004), where he discussed that the difference in environmental conditions can cause differences in the response of the same species to the same host. Kaliyati, Mapope and Manyangarirwa (2023) reveal that Elad and Pertot (2014) state that predicted climatic changes are expected to affect pathogen development and survival rates and modify host susceptibility, resulting in changes in the impact of diseases on crops; hence the effects of these climatic changes will differ by pathosystem and geographical region (Trabelsi et al. 2017). Environmental factors can affect phytochemical profiles that are responsible for controlling pathogen effect on plants of the same species (Eamon 2023), hence resulting in different responses that were noted in the same species but different accessions.

The difference in response of accessions to disease severity and disease incidence was described by Agrios (2004) about the effects of gene conditioning resistance contributing to the potential development of one of the physiological and morphological characters that contribute to disease resistance on host plants because of their differences in genetic makeup. As these accessions portray differences in physical appearance, which are a result of different genes, though they are all C. gynandra plants, these may have caused the differences in response to the host from the pathogen during this research. Effects of genetic variability were observed with significant variability in phytochemical production in five different varieties of Asparagaceae plant species among species (Mohammed et al. 2025; Pandit et al. 2022) described the process of plant selection and breeding, which has proved to be important in comparing varieties and selecting those that can fight against pathogen development and produce resistant cultivars, and this is the process that was used in accession evaluation in this case. Cleome gynandra plants have been observed by Behera et al. (2024), Meda et al. (2013), Mohammed et al. (2025), Kutsukutsa et al. (2014), Wanjala, Gicheru and Mwangi (2020) to produce phytochemicals that are responsible in reducing pathogen effect on the plant (Dantas et al. 2025; Deresa & Diriba 2023; Mohammed et al. 2025), and this will help in the selection of accessions that can resist pathogen effect better that other accessions as this was discussed by Oluwadamilola et al. (2023) that genetic variability in plants affect the production of phytochemicals. All other species used in this research were pathogenic to all the tested accessions. Fusarium verticillioides and C. pseudocladosporioides against Accession 1 (CGZIM) had no disease incidence and severity recorded. Fusarium equiseti had no disease severity and incidences recorded on evaluations against Accession 2 (CGGUR). Accession 2 had more isolates with low severity and incidence scores, followed by Accession 1, then Accessions 3 and 4. Accessions 2 and 3 are recommended for further evaluations to be used as commercial accessions in the growing of C. gynandra. In the case of disease management, all the accessions can be evaluated for disease management against the isolates to reduce damage by the isolates, as disease progress was noted with the initial day of evaluation, with low severity scores. Accessions 3 and 4 (CGMRGP-Marondera and CG KENYA) have been recommended by Mativavarira et al. (2024) for future genetic improvements in research, where they assessed the breeding priorities and preferences among landraces in Zimbabwe.

Pathogen inoculation that is followed by low disease incidences that are associated with low disease severity may have been attributed to the fact that was discussed by Agrios (2004), that some plant species being susceptible to a pathogen only at a particular growth stage, if the pathogen is absent or inactive at that particular time, such plants avoid becoming infected. Alternaria has been seen to affect fully grown, mature and senescent plant parts.

This was observed during this research, where all Alternaria and A. laibachii species had low disease incidences and severity scores that had high scores in the last 3 weeks of evaluation. This might be because individual plants, even those possessing genetically determined predispositions, are not susceptible to a particular pathogen caused by induced plant susceptible responses mediated by S-genes (Gorshkov & Tsers 2021). Pathogen inoculation followed by high disease incidence associated with increased disease severity has been observed in Fusarium species and S. striticum, and this is linked to the observation made by Agrios (2004), that some species of Botrytis and powdery mildew can affect young tissues, stems and fruits. This might be as a result of the fact that phytopathogens can make plants more susceptible via production of virulence factors that include effector proteins, pathogen-produced phytohormones, some siderophoresand some toxins, as discussed by Gorshkov and Tsers (2021) and Gilchrist & Grogan (1975).

All other species used in this research were pathogenic to all the tested accessions. Fusarium verticillioides and C. pseudocladosporioides against Accession 1 had no disease incidence and severity recorded. Fusarium equiseti had no disease severity or incidence recorded during evaluations compared with Accession 2. Accession 2 had more isolates with low severity and incidence scores, followed by Accession 1 and then Accessions 3 and 4. Accessions 2 and 3 are recommended for further evaluations to be used as commercial accessions in the growing of C. gynandra. In the case of disease management, all the accessions can be evaluated for disease management against the isolates to reduce damage by the isolates, as disease progress was noted with the initial day of evaluation, with low severity scores. Accessions 3 and 4 (CGMRGP-Marondera and CG KENYA) have been recommended by Mativavarira et al. (2024) for future genetic improvements.