Management of root-knot nematode (Meloidogyne incognita) in cucumber using different botanicals

Introduction

Cucumber (Cucumis sativus L.), a widely cultivated popular vegetable crop in the gourd family, Cucurbitaceae grown broadly throughout the world. It is eaten as a popular domestic fruit called kakadi or kheera in Hindi. It is being used in many ways in the daily diet of humans and widely cultivated worldwide (Bhati and Baheti, 2021) [3] . There are so many health benefits of cucumber as these are rich in antioxidants and help in weight loss (Kumar et al., 2010) [9] . In view of the year demand, cucumber is the second most popular crop grown under protected or covered structures (Mao et al., 2016) [11] . However, continuous cultivation of cucumber and adequate soil moisture in greenhouses, promote the development of certain diseases in severe form, especially the nematode diseases such as root-knot caused by Meloidogyne spp. (Khan et al., 2012a) [8] . Nematodes, being ubiquitous browsers and a hidden enemy, cause discernible damage to the crop because of a longer duration with a deeper root system. They have a needle-like structure called a stylet that helps them to pierce the plant cell walls and reach the juicy contents on which they feed (Bernard et al., 2017) [1] . Root-knot nematodes is a major pathogen affecting cucumber production globally, particularly in regions where the crop is grown under protected environments such as polyhouses and greenhouses (Tariq et al, 2025; Bhati and Baheti, 2020; Gine et al., 2014) [12,2,4] . It is a serious pest of vegetable crops (Khan, 2012) [8] , and cucumber is highly susceptible to M. incognita (Huang et al., 2016) [6] . Root-knot nematodes, Meloidogyne spp., are considered among the most important PPNs worldwide, with M. incognita, M. javanica, M. arenaria and M. hapla being the most damaging species (Greco and Vito, 2009) [5] . The extent of damage and crop loss, depends on the initial nematode population density at planting making it crucial to establish a threshold for effective management (Jain, 1992) [7] .

Materials and Methods

The experiment was under taken to find out effective botanicals for management of root-knot nematode in cucumber. Plastic pots of 15 cm diameter were disinfected using 4% formaldehyde solution. After drying, pots were filled with nematode infected soil (1 kg/pot) incorporating fresh chopped leaves @ 0.1% (w/w). These botanicals were allowed for decomposition for 20 days. After 20 days, three seeds of cucumber var. GCU-1 were sown per pot and thinned down upon germination by keeping one plant/pot. Watering and plant protection measurements were taken as per the requirements. The plants were removed carefully after 45 days of sowing and observations were recorded on germination count/pot, vine length (cm) (at 45 days after seeding), fresh shoot and root weights (g), soil nematode population/pot and root nematode population/g/plant, rootknot index (0-5 scale) (Taylor and Sasser, 1978). Finally, data were subjected to statistical analysis using Duncan's New Multiple Range Test (DNMRT)

Results and Discussion

Germination percentage

Cent percent seeds were germinated in both the years as well as in pooled, indicating that there was no adverse effect of different botanicals on seed germination. However, during 2023 and 2024, 11.11% reduction in seed germination was observed in treatment T 4 and T 3 respectively (Table 1).

Significant differences were recorded in vine length between control and all other treatments during year 2023, 2024 and in pooled analysis. The results for 2023, 2024, and pooled data provide a comprehensive picture of treatment effect on plant growth, along with their percentage increases over control. The findings clearly show that different treatments exerted significant influences on growth, producing distinct levels of improvement compared to the baseline. Maximum vine length 152.00,155.33 and 153.67 were registered in treatment T 1 (C. procera) followed by T 2 and T 6 with 27.33, 26.98 and 27.34 percent increase in vine length during 2023 and 2024 as well as in pooled respectively (Table 1). All three treatments (T 1 , T 2 and T 6 ) remained at par with each other. Significantly less vine length was recorded in control. Rest of the treatments has mediocre effect.

The results on fresh shoot weight across 2023, 2024, and pooled analysis highlight a clear and consistent impact of different treatments compared to the untreated control. Data presented in table 2 revealed that treatment of C. procera yielded maximum fresh shoot weight among all the treatments. During 2023 and pooled analysis treatment T 1 give significantly higher i.e. 9.21 and 9.27 g fresh shoot weight respectively followed by T 2 . Minimum fresh shoot weight 5.69 and 5.93 g was noticed in control in the year 2023 as well as in pooled respectively. Rest of the treatments had intermediate effect and statistically at par with each other. In the year 2024 treatment T 1 remained on top with maximum (9.32 g) fresh shoot weight followed by T 2 and T 6 .

The data on fresh root weight (Table 2) indicated similar trend as observed in plant fresh shoot weight during both the years and in pooled analysis. The data on fresh root weight (g) across 2023, 2024, and pooled analysis revealed a strong and highly significant influence of treatments compared to the untreated control. Importantly, the year effect and year × treatment interaction (Y × T) were non-significant. The treatment T 1: C. procera (Madar) recorded the highest fresh root weight, with 3.16 g in 2023 and 3.02 g in 2024. The pooled mean was 3.09 g, representing a remarkable 183.2% increase over control followed by the treatment T 2: A. indica (Neem) with 2.61 g (150.96% increase) in 2023 and 2.49 g (120.35% increase) in 2024. The pooled mean was 2.55 g, with an average increase of 136.00% over control. However, minimum fresh root weight was observed in T 7 (control) during 2023, 2024 as well as pooled over the years.

Root-knot index (0-5)

Significant differences were recorded in root-knot index between control and all treatments during year 2023, 2024 and in pooled analysis. The data on root-knot index (RKI) recorded during 2023, 2024, and pooled analysis clearly show that all treatments significantly reduced root-knot index compared to the untreated control, though the degree of reduction varied among treatments. The year effect and year × treatment (Y × T) interaction were non-significant, confirming consistency of treatment effects across seasons. The treatment T 1: C. procera (Madar) was the most effective treatment recording significantly less RKI i.e. 2.33, 2.67 and 2.50 with 53.33, 46.67 and 50.00% reduction in RKI over control in the year 2023, 2024 and pooled results respectively. Next best effective treatment is T 2 which remain at par with T 1 (Table 3). Maximum RKI (5.00) was recorded in control.

Soil nematode population

During 2023, there was significantly less soil nematode population (2130) in the treatment of C. procera followed by treatment of A. indica (2433) and B. juncea (2640) and not differ significantly from each other. Control had maximum soil nematode population (3360) which statistically at par with T 3 , T 4 , T 5 and T 7 .

In the year 2024, lowest soil nematode population was recorded in the treatment T 1 followed by T 2 . However, statistically not differ from each other. Control had maximum (3420) soil nematode population and remain at par with rest of the treatments except T 1 and T 2 (Table 3). The same trend was observed when data pooled over the year.

Root nematode population

Perusal of data presented in table 4 number of females indicated differences among botanicals except T4. Though the magnitude of reduction varied among treatments. In the year 2023, botanical C. procera turnout as a most effective treatment with significantly less (78.00) female population as compare to remaining treatments. However, it remains at par with T 2 . Maximum number of female (147.33, 165.00 and 156.17 respectively) was observed in control during 2023, 2024 and pooled over year. Same trend was observed in 2024 and pooled over years. In the year 2023, number of eggmasses were minimum (3.00) in the treatment T 1 followed by T 2 (4.00), T 5 (5.33), T 6 (4.33) and T 7 (5.00) not differing significantly from each other (Table 4). Control has maximum (14.67) The present study emphasized the exploration of botanicals as eco-friendly approaches for the management of root-knot nematodes (Meloidogyne incognita). The results clearly demonstrated that among the tested treatments, T 1: C. procera Ait. (Madar) was the most effective, followed by the treatments T 2: A. indica A. Juss (Neem), in depleting nematode populations and improving plant growth parameters. These findings are in line with earlier reports, highlighting the potential of certain botanicals in nematode suppression. Several researchers have previously documented the efficacy of organic amendments and plantbased materials for nematode management. For instance, incorporation of naffatia (Ipomoea fistulosa), water hyacinth (Eichhornia crassipes), aak (C. procera), or congress grass (Parthenium hysterophorus) into soil 15 days prior to seeding was found highly effective in controlling root-knot disease in nematode-infested tomato nurseries. Similarly, the application of madar (C. procera) and neem (A. indica) leaves showed reduction of root-knot index and also enhance plant growth traits in crops like bitter gourd and bottle gourd (Venkatesan, 2009; Singh and Patel, 2015) [14,13] . These consistent findings across different host crops highlight the versatility of botanicals such as C. procera and A. indica in nematode management. Their effectiveness could be attributed to bioactive compounds present in the plant tissues, which may act directly as nematicides or indirectly by improving soil health and promoting antagonistic microbial activity. Thus, the integration of botanicals like madar and neem into sustainable agricultural practices not only reduces the dependency on chemical nematicides but also provides long-term ecological benefits by ensuring safer crop production and maintaining soil fertility.

Conclusion

The data of the experiment showed that different botanicals significantly effective in improving plant growth character to the varied degree and reduce nematode reproduction over control. Among all the botanicals soil application of the treatment C. procera, 20 days prior to crop seeding reduce soil nematode population and improve crop growth followed by soil application of the treatment of A. indica.

Acknowledgement

AcknowledgementThe authors humbly acknowledge the facilities and assistance of the Hon'ble Director of Research and Dean P.G. Studies, Sardarkrushinagar Dantiwada Agricultural University, S.K. Nagar.

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