Anwesha Sharma1 and Popy Bora2
1Ph.D Scholar, Department of Plant Pathology, Assam Agricultural University, Jorhat, Assam
2Senior Scientist, AAU-ARRI, Titabor, Jorhat, Assam
Abstract
Saffron (Crocus sativus L.), often referred to as “Red Gold,” is the world’s most valuable spice due to its unique aroma, colouring capacity, and diverse pharmacological properties. Despite its economic and cultural importance, saffron cultivation suffers significant yield and quality losses due to diseases, pests, and abiotic stresses. Among them, corm and bulb rots, bacterial soft rot, violet root rot, and viral infections such as Turnip mosaic virus are predominant. These diseases not only reduce saffron productivity but also threaten the livelihoods of farming communities, especially in regions where saffron contributes significantly to local and national economies. This article consolidates information on major saffron diseases, their aetiology, epidemiology, yield losses, and integrated management strategies, with emphasis on eco-friendly and sustainable approaches.
- Introduction
Saffron (Crocus sativus L.) is a sterile triploid geophyte cultivated for its dried red stigmas, which are used as a spice, dye, and medicinal ingredient. It is considered the costliest spice globally, often valued higher than gold per unit weight, hence earning the epithet “Red Gold.” The spice has numerous bioactive compounds such as crocin, picrocrocin, and safranal, which account for its medicinal, antioxidant, and therapeutic properties (Gupta et al., 2021).
Globally, Iran is the largest saffron producer, contributing more than 85% of the total supply, with Khorasan Razavi province alone cultivating 82,712 ha. In India, saffron is cultivated mainly in Jammu and Kashmir, where 5,707 ha are under saffron cultivation, accounting for most of the domestic production. However, Indian productivity (2.0-2.5 kg/ha) remains much lower than global averages, primarily due to poor planting material quality, biotic stresses, and inadequate crop management practices (Rather et al., 2022).
Saffron plays a significant role in local economies, particularly in Kashmir, where it contributes substantially to agricultural GDP and household income. However, annual yield losses due to diseases and pests can reach alarming levels, thereby reducing farmers’ profitability and affecting market stability. Among the diseases, fungal and bacterial rots of the corm are the most destructive, compromising both yield and quality.
- Economic Impact of Saffron Diseases
Corm and bulb rots alone are responsible for 21% infestation of saffron area in Kashmir, severely reducing its propagation potential and productivity. Bacterial rots may lead up to an 80% reduction in flowering, drastically affecting yields. Viral infections further reduce the quality and marketability of stigmas. Collectively, these diseases account for substantial annual revenue losses in saffron-growing regions, threatening farmer livelihoods and regional GDP contributions.
- Major Diseases of Saffron
3.1 Corm Rot
Corm rot is the most destructive disease of saffron and has been reported as the primary constraint in corm propagation and yield stability. It is a complex disease caused by several soil-borne fungi, including Fusarium oxysporum, F. solani, Rhizoctonia crocorum, Macrophomina phaseolina, Mucor spp., Penicillium spp., and Sclerotium rolfsii. Among these, F. oxysporum and F. solani have been identified as the most devastating pathogens in Kashmir, where saffron cultivation is concentrated (Gupta et al., 2021).
The disease usually initiates with the yellowing and premature drying of leaves. Upon excavation, infected corms show brown discoloured centres that extend deep into the fleshy tissues, often leading to sunken, rough lesions that are externally visible. Lesions are frequently concentrated near the base but can develop anywhere on the corm surface. In severe infections, the discoloured areas penetrate the entire tissue, resulting in hard, scaly patches. The attached roots also appear necrotic and decayed, and the severely affected corms rot completely before sprouting in the following season, thereby reducing propagation material. The perpetuation of the disease is closely linked to the persistence of inoculum in the soil, either through infected corm debris or as resting propagules of the pathogens. Secondary spread is facilitated by conidia of Fusarium spp. Environmental conditions such as excessive soil moisture, poor drainage, continuous monocropping, and extended planting cycles exacerbate the disease (Bashir et al., 2025).
3.2 Bulb Rot
Bulb rot, primarily incited by Sclerotium rolfsii, is another destructive soil-borne disease of saffron. The initial symptoms manifest as irregular, sunken brown lesions beneath the corm scales, which later expand and coalesce. White mycelial mats frequently develop over infected tissues, often followed by the formation of sclerotia, which serve as survival structures. Above ground, the foliage of infected plants tends to dry progressively from the tips downward, a symptom often mistaken for nutrient deficiency or drought stress. The pathogen survives in soil and infected residues through sclerotia, which remain viable for several years. These structures are disseminated through irrigation water, rain splashes, and agricultural implements. Moisture stress combined with elevated soil temperatures provides conducive conditions for the disease to develop (Kalha et al., 2007).
3.3 Bacterial Soft Rot
Bacterial soft rot in saffron, caused by Burkholderia spp., is considered one of the most devastating bacterial diseases, capable of reducing flowering by up to 80% during severe infestation. The disease is first manifested through the yellowing of foliage, which soon collapses, followed by the death of the plant. Infected corms exhibit wrinkling and may produce a characteristic yellowish pigment, although in some cases, pigmentation is absent. Such corms often fail to sprout, reducing stand establishment and regeneration. The bacterium survives in association with dead plant material and spreads through soil particles, irrigation water, and rain splashes. Warm, humid conditions coupled with excessive irrigation provide ideal conditions for infection and disease development (Fiori et al., 2011).
3.4 Violet Root Rot
Violet root rot, also known as “copper web,” is caused by Rhizoctonia crocorum and its perfect stage Helicobasidium purpureum. It is a soil-borne disease that leads to significant stand losses, often appearing as patchy plant death across fields. A key symptom is the development of violet or purple mycelial mats around corm scales and roots. Numerous sclerotia-like bodies can be seen embedded in the infected tissue. Roots infected by the pathogen become entangled in a dense violet fungal mat, eventually decaying. The pathogen survives in the soil through resistant sclerotia, allowing it to persist across growing seasons. Disease development is favored by light-textured soils with high humidity, making poorly drained and humid fields more susceptible (Zadoks, 1981).
3.5 Viral Diseases-Turnip Mosaic Virus (TuMV)
Among viral diseases affecting saffron, Turnip mosaic virus (TuMV) is particularly damaging. The virus is transmitted by several aphid species in a non-persistent manner, making vector management crucial. Infected plants exhibit stunted growth, chlorotic mottling, mosaic leaf patterns, and necrotic lesions. Flowers in affected plants are often deformed, reducing stigma quality and commercial value. The virus does not perpetuate independently in soil or debris; instead, its spread is entirely dependent on aphid populations. Warm conditions favour aphid multiplication, thereby intensifying disease incidence (Shamshiri et al., 2025).
Control measures primarily depend on preventive and vector management strategies. Clean cultivation and strict field sanitation help reduce primary sources of inoculum. Planting healthy corms and maintaining proper plant spacing decreases the likelihood of spread. Mechanical control with yellow sticky traps (4-5 traps per acre) effectively lowers aphid populations. Additionally, botanical interventions like neem oil or canola oil sprays help suppress vector activity, while chemical control with systemic insecticides such as imidacloprid offers targeted control during peak aphid infestations.
- Integrated Disease Management (IDM) Approaches
Effective management of saffron diseases requires a holistic approach that combines cultural, biological, and chemical practices with vector management and long-term breeding strategies. The fragile nature of saffron cultivation, coupled with its economic significance, necessitates disease control practices that are both sustainable and environmentally compatible. The major pillars of integrated disease management in saffron are discussed below in detail.
4.1 Cultural Practices
Cultural control remains the foundation of disease management in saffron cultivation. Adoption of crop rotation with non-host species such as linseed, oat, or maize reduces the buildup of soil-borne inoculum, particularly of Fusarium spp. And Sclerotium rolfsii. Sanitation practices, including the removal and destruction of infected residues, limit the perpetuation of pathogens from one season to the next. Improved field drainage and tillage help minimize the risk of diseases favoured by excessive soil moisture, such as corm rot and bacterial soft rot. Moreover, the use of certified disease-free corms is essential, as infected planting material serves as the primary vehicle for pathogen spread. Collectively, these measures not only suppress pathogen populations but also create a microenvironment less favourable for disease development.
4.2 Biological Control
The application of beneficial microorganisms has emerged as a sustainable alternative to chemical control (Sharma and Bora, 2025). Among these, Trichoderma spp. have been extensively studied and shown to exert antagonistic effects on major saffron pathogens through mechanisms such as mycoparasitism, competition, and induction of systemic resistance (Sharma, 2024). Soil incorporation of Trichoderma viride or T. harzianum at rates of 2.5 kg/ha has consistently reduced corm rot incidence while enhancing plant vigour. In addition, biofertilizers, such as Azospirillum spp., improve nutrient uptake and root development, indirectly strengthening plant resistance. Organic amendments, particularly mustard cake, when used in conjunction with Trichoderma, provide additional benefits by enriching soil organic matter, fostering microbial diversity, and reducing pathogen load. These biological interventions offer eco-friendly solutions that can be integrated with other management tactics for long-term disease suppression.
4.3 Chemical Interventions
Despite growing emphasis on eco-friendly approaches, chemical interventions remain indispensable, particularly under severe disease pressure. Seed treatment with systemic fungicides, such as carbendazim and myclobutanil, has proven effective in reducing the initial inoculum load carried by corms. Foliar application of broad-spectrum fungicides like mancozeb or copper oxychloride provides additional protection against fungal and bacterial diseases. However, reliance on chemical control alone poses risks of resistance development, environmental contamination, and residue accumulation in stigmas. Therefore, chemical fungicides are best employed as a component of integrated modules, combined with biological and cultural measures, and preferably applied in a targeted rather than prophylactic manner.
4.4 Vector Management
Viral diseases, particularly those caused by Turnip mosaic virus (TuMV), are primarily spread through aphid vectors. Hence, vector management is a critical component of IDM. Mechanical methods, such as the installation of yellow sticky traps (4–5 traps per acre), significantly reduce aphid populations. Botanical pesticides, including neem and canola oil sprays, interfere with aphid feeding behaviour and reduce transmission efficiency (Saha et al., 2025). During high vector pressure, systemic insecticides, such as imidacloprid, offer effective suppression. The integration of these methods not only minimizes the risk of viral spread but also contributes to overall crop health by limiting insect-associated damage.
- Conclusion
The productivity of saffron is significantly constrained by a range of fungal, bacterial, and viral diseases, with corm rot emerging as the most serious bottleneck. Since corms serve as both propagation material and economic units, their health is central to successful saffron cultivation. Integrated disease management involving clean planting material, biological control, cultural practices, and judicious use of chemicals remains the most viable approach. Long-term solutions should focus on breeding for resistance and developing location-specific IDM modules to ensure sustainable saffron production and safeguard its economic value. Long-term sustainability in saffron disease management will depend on innovative strategies that address the limitations of current practices. Breeding for resistant varieties remains the most promising approach, although progress is constrained by the sterile triploid nature of saffron. Advances in molecular breeding, the integration of artificial intelligence (AI) and digital agriculture tools have opened new avenues for saffron disease management, enabling predictive modelling of outbreaks, early detection through image-based diagnostics, and decision-support systems that guide farmers in adopting timely and precise interventions, may help overcome these barriers (Sharma and Bora, 2024; Sharma et al., 2024). Enhanced disease surveillance systems, incorporating field-based diagnostics and molecular tools, will be vital for early detection and rapid response to disease outbreaks. Farmer training programs focusing on IDM principles, safe pesticide use, and the importance of biological inputs are also crucial to ensure widespread adoption of best practices. Moreover, research should emphasize developing location-specific IDM modules tailored to the unique agro-climatic conditions of saffron-growing regions.
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