Integrated management of mango anthracnose using botanicals, natural inputs and fungicides under in-vitro and in-vivo conditions

Introduction

Mango (Mangifera indica L.), widely known as the "King of Fruits", is one of India's most important tropical crops. Although the country is the world's largest mango producer and a major exporter, post-harvest losses of 25-40% remain a serious challenge. Among these, anthracnose caused by Colletotrichum gloeosporioides is the most destructive disease. The pathogen infects mango tissues during flowering and stays latent until fruit ripening, leading to dark, sunken lesions and severe spoilage, ultimately reducing marketability and economic returns. Conventional control of anthracnose largely depends on synthetic fungicides. While effective, their overuse has resulted in issues such as fungicide resistance, chemical residues, environmental risks and growing consumer health concerns. These drawbacks have encouraged the exploration of safer, eco-friendly alternatives. Botanicals like neem, garlic, tulsi and ginger contain bioactive compounds with strong antifungal activity that can inhibit spore germination and mycelial growth. Natural farming inputs including cow urine, fermented buttermilk, jeevamrutha, panchagavya and sonthastra are also gaining importance due to their antimicrobial potential and their ability to enhance fruit quality and shelf life. Newer-generation fungicides, particularly triazole-strobilurin combinations, have shown excellent control of C. gloeosporioides with reduced residue risks when used judiciously. Evaluating these treatments under both in-vitro and in-vivo conditions is crucial for identifying effective and practical disease management options. In-vitro studies provide insights into direct antifungal activity, while in-vivo trials reflect real post-harvest performance. Therefore, the present study investigates the inhibitory effects of selected plant extracts, natural farming inputs and fungicides against C. gloeosporioides, aiming to reduce post-harvest losses and support sustainable anthracnose management in mango.

Evaluation of Plant Extracts under In-vitro Conditions

Ten medicinal plants were screened for antifungal activity using the poisoned food technique (Grover and Moore, 1962) [9] . Crude extracts of leaves, roots, or rhizomes were prepared by homogenizing 100 g of fresh plant material in 100 ml of double-distilled water, filtering through muslin cloth. The resulting 100% extract was incorporated into PDA medium at 5% and 10% concentrations (i.e., 2 ml and 4 ml extract in 40 ml PDA, respectively). Twenty milliliters of the amended medium were poured into Petri plates, inoculated with 5 mm mycelial discs of a 7-day-old C. gloeosporioides culture and incubated at 27±2 °C. Radial growth and percentage inhibition were recorded using Vincent's formula (1947).

Evaluation of Natural Farming Inputs under In-vitro Conditions

Seven traditional inputs were tested for their antifungal efficacy at 5% and 10% concentrations using the poisoned food technique. Inputs such as cow urine, sonthastra, fermented buttermilk, panchagavya, jeevamrutha, beejamrutha and herbal kunapajala were either freshly prepared or obtained from reputed sources. Each treatment was mixed into sterilized PDA, poured into Petri plates, inoculated with 5 mm fungal discs and incubated at 27±2 °C. Observations on radial growth and percentage inhibition were recorded.

Evaluation of Fungicides under In-vitro Conditions

Nine fungicides in single or combined formulations were evaluated at 100 ppm and 200 ppm concentrations using the poisoned food technique (Nene and Thapliyal, 1993) [11] . Fungicides were incorporated into molten PDA medium and poured into Petri dishes. The plates were inoculated with 5 mm mycelial discs from a 5 day old C. gloeosporioides culture and incubated at 27±2 °C. Observations were made on mycelial growth and inhibition. All experiments were conducted using a completely randomized design (CRD) with two replications. Growth inhibition was calculated using Vincent's formula (1947):

The observations recorded during the experiment included radial growth (mm) and growth inhibition (%). Where, DC refers to the mean diameter of the mycelium colony in the control treatment (mm) and DT refers to the mean diameter of the mycelium colony in the treated set (mm).

Evaluation of Plant Extracts and Fungicides under Invivo Conditions

In-vivo Evaluation of Plant Extracts Five plant extracts (Garlic, Neem, Eucalyptus, Basil and Ginger) were tested at 5% and 10% concentrations. Semiripe mango fruits (cv. Dasheri) were surface sterilized with 1% sodium hypochlorite and rinsed with sterile water. Two treatment approaches were followed, Pre-inoculation: Fruits were dipped in treatment solutions for 5 minutes, air-dried and then inoculated by the pin-prick method using a conidial suspension (1 × 10⁵ spores/ml). Fruits were incubated in polythene bags containing moist sterile cotton. Postinoculation: Fruits were first inoculated and, after 12 hours, treated by dipping in solutions for 5 minutes. Incubation followed the same procedure as above. Disease severity was assessed on the 4th day post-inoculation using a standard 0-5 disease grading scale.

In-vivo Evaluation of Fungicides

Five fungicide formulations were selected based on in-vitro efficacy and tested at 100 ppm and 200 ppm concentrations. The same methodology for fruit sterilization, inoculation and incubation was followed as described above for plant extracts. Disease assessment was carried out on day 4 using the same scale.

Grade

Results and Discussion

In-vitro Evaluation of Plant Extracts Among the various treatments, T [1] , Niazi et al. (2022) [10] and Shinde et al. (2024) [17] found that garlic clove extract yielded the least mycelium growth and the highest inhibition percentages against different C. gloeosporioides at different concentrations.

In-vitro Evaluation of Natural Inputs

In the evaluation of natural farming inputs, T 1 (Cow urine 10%) displayed the highest mycelial inhibition (91.38%), proving to be statistically superior. The next best natural farming input was Sonthastra, which demonstrated notable antifungal activity with a colony diameter of 16.84 mm and an inhibition percentage of 81.28 per cent at the same concentration. In contrast, the lowest inhibition was observed in Herbal Kunapajala at the 5 per cent concentration, where only 40.34 per cent inhibition was recorded, resulting in a relatively larger mycelial growth of 53.69 mm. These observations are in line with the results reported by previous researchers such as Kulkarni (2009) [7] , Kambar et al. (2013) [6] and Salam et al. (2018) [15] , who also found that natural farming inputs were effectively suppress the growth of C. gloeosporioides under in-vitro conditions. Furthermore, Ashlesha and Paul (2014) [2] and Patel et al.

(2024) [13] revealed that apart from cow urine, other inputs such as Panchagavya, Jeevamrutha and Beejamrutha have also shown promising results in inhibiting the growth of Colletotrichum spp., further validating the findings of the present study.

In-vitro Evaluation of Fungicides

The fungicide T 6 demonstrated the highest inhibition (98.47%), making it the most effective treatment against the pathogen. It was found statistically at par with T 5 . On the other hand, the least effective treatment in suppressing the pathogen was Carbendazim 50% WP at 100 ppm, which recorded the lowest mycelial growth inhibition of only 63.39 per cent, corresponding to a maximum mycelial diameter of 32.94 mm. This indicates that Carbendazim at the lower tested concentration is relatively less effective in managing_C.gloeosporioides_under_invitro_conditions_co mpared_to_the_newer_combination_fungicides.

The present findings are in agreement with the results reported by several previous researchers such as Chaudhari and Gohel (2016) [3] , Dev and Narendrappa (2016) [4] , Kumari et al. (2017) [8] , Sharma et al. (2019) [16] , Padghan et al. (2023) [12] , Ekabote et al. (2024) [5] and Raut (2024) [14] . These studies consistently demonstrated that tebuconazole 50% + trifloxystrobin 25% WG and azoxystrobin 18.2% + difenoconazole 11.4% w/w SC are among the most effective fungicide combinations for controlling Colletotrichum spp. under laboratory conditions at varying concentrations

In-vivo Evaluation of Plant Extracts

Under the pre-inoculation method, garlic clove extract (10%) was the most effective treatment, recording the lowest disease severity of 5.56%. Ginger rhizome extract (10%) was the second most effective, showing 7.41% disease severity. In contrast, eucalyptus leaf extract (5%) was the least effective, with the highest disease severity of 16.67%, indicating its lower antifungal efficacy.

On the 4th day after inoculation, garlic clove extract (10%) continued to show the highest effectiveness, reducing disease severity to 7.41%. Ginger rhizome extract (10%) remained the second most effective, with 11.11% disease severity. Eucalyptus leaf extract (5%) again showed the least efficacy, recording 24.07% disease severity, confirming its limited role in controlling C. gloeosporioides.

Conclusion

The study conclusively demonstrated that garlic and ginger extracts at 10% concentration possess strong antifungal activity against C. gloeosporioides, with garlic emerging as the most effective botanical in both in-vitro and in-vivo evaluations. Among natural farming inputs, fresh cow urine (10%) exhibited the highest mycelial inhibition, suggesting its potential role in organic disease management practices. New-generation fungicides, especially tebuconazole 50% + trifloxystrobin 25% WG and azoxystrobin 18.2% + difenoconazole 11.4% SC at 200 ppm, provided superior control over the pathogen under both laboratory and fruit application conditions. Overall, the integration of these effective botanicals, natural inputs and low-residue fungicides offers a promising, sustainable alternative to synthetic chemical-based disease management. This approach not only reduces the dependence on hazardous fungicides but also contributes to improving fruit quality, shelf life and profitability in mango cultivation.

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