Fungal Diseases of Wheat in Punjab, Pakistan: Epidemiology, Climate Interactions, and Sustainable Management Strategies

1. Introduction

Wheat (Triticum aestivum L.) is among the three staple crops worldwide and contributes about 35% of the dietary requirements of the global population. In 2022, around 778 million metric tons of wheat were produced collectively by China, India, Russia, and the European Union (Sharma and Kumar Sharma 2025). In Pakistan, wheat accounts for 70% of the population's daily food intake, making it the country's most important cereal crop (Miller Magazine 2024). Punjab is the major wheat-producing province, accounting for 70% of national wheat production, followed by Sindh at 20% (A et al. 2022).

Wheat production in Pakistan increased to 29.61 million tonnes in 2025–26, compared with 28.40 million tonnes in the previous year, representing an increase of 4.3%. This improvement has been associated with favorable sowing conditions, sufficient irrigation water, quality fertilizers, and the use of certified seeds (Government of Pakistan 2026).

In Punjab, Bahawalnagar district ranked first with 1.557 million tonnes of the province's annual wheat production, followed by Rahim Yar Khan at 1.211 million tonnes (Ministry of National Food Security & Research 2025). Southern Punjab holds a vast agro-ecological zone shaped by the semi-arid Indus Basin, comprising six districts, each presenting unique topographic and microclimatic conditions (Ali et al. 2022). The region has hot, dry summers and mild winters, with wheat generally grown from November to April. Rising temperatures, declining rainfall, and high humidity may create favorable conditions for fungal disease outbreaks (Shah et al. 2024).

Fungal diseases are a leading biotic stress affecting wheat production in Pakistan and may cause yield losses ranging from 10 to 70%, depending on the pathogen, variety, and season (Ali et al. 2026). Approximately 200 wheat pathogens have been identified. In Punjab, the important fungal groups include rust fungi (Puccinia spp.), Fusarium species, and seed-borne mycoflora, including Alternaria, Bipolaris, and Aspergillus (Khan et al. 2023a).

For disease management, excessive reliance on synthetic fungicides raises concerns related to fungicide resistance, environmental contamination, mycotoxin-related food safety risks, and the health of farmer families (Maulenbay and Rsaliyev 2024). Eco-friendly alternatives, including biological control, botanical extracts, and host resistance breeding, are receiving scientific and policy attention both globally and in Pakistan.

This review covers relevant peer-reviewed studies to: (1) characterize the major fungal pathogens of wheat in Punjab, Pakistan; (2) analyze the associated disease dynamics; (3) evaluate eco-friendly management strategies with documented efficacy; and (4) outline the gaps and priorities for future research in the region. This work is intended to serve researchers, agricultural extension personnel, and policymakers committed to sustaining wheat production in Punjab.

2. Major Fungal Pathogens of Wheat in Punjab, Pakistan

Table 1 summarizes the principal fungal pathogens reviewed, their diseases, affected growth stages, typical yield loss ranges, and primary distribution in Punjab.

2.1. Stripe Rust—Puccinia striiformis f. sp. tritici (Pst)

Stripe (yellow) rust is caused by Puccinia striiformis f. sp. tritici in wheat and is considered one of the major diseases affecting wheat worldwide. Under severe infection, yield loss can reach up to 70% (Kleczewski et al. 2020). In Pakistan, stripe rust has been documented since 1786 and is currently reported across wheat-growing regions from southern to northern Pakistan (Bux et al. 2012). Pst is an obligate biotrophic parasite that relies on wind-dispersed urediniospores capable of long-distance travel.

Khan et al. (2023) evaluated seven commercial wheat varieties during the 2019 to 2021 seasons and found that naturally occurring stripe rust caused severe infection in widely cultivated varieties across Punjab, including Johar-16, Galaxy-13, and Sehar-06.

Abbas et al. (2024) investigated 349 Pakistani and Chinese genotypes and reported that Yr5 and Yr15 genes were effective in historic lines and recent Pakistani cultivars, while Yr15, Yr26, and YrSp showed effective resistance against current stripe rust strains. The study also found that Yr17, Yr26, and YrSp were overused in the Pakistani breeding pool, which may contribute to continued susceptibility. Yield losses may range from 10 to 70% in susceptible cultivars, and during intense epidemic periods, yield loss may reach 100%.

2.2. Leaf Rust—Puccinia triticina

Leaf rust (brown rust) is caused by Puccinia triticina and is the most commonly spread rust disease of wheat globally (Marone et al. 2024). Unlike stripe rust, this pathogen prefers warmer temperatures between 15°C and 22°C (Hassan et al. 2022). Leaf rust remains a serious threat to wheat production across Pakistan.

Khan et al. (2021) documented a national surveillance effort conducted from 2016 to 2018, showing consistently high disease pressure and susceptible reactions across multiple locations; in 2017, disease severity exceeded 60% in multiple fields. Yield losses of 20 to 40% are typical in vulnerable varieties under moderate to high disease pressure.

Ali et al. (2026) modeled the relationship between leaf rust severity and crop performance in Punjab, showing a clear decline in harvest quality as disease severity increased, providing a quantitative basis for resistance-breeding priorities.

2.3. Fusarium Head Blight (FHB)—Fusarium graminearum

Fusarium head blight, also known as scab, is a major wheat disease caused by the fungus Fusarium graminearum Schwabe. Yield loss can reach up to 80% of the crop, threatening approximately 789 million tons of global wheat production (Alisaac and Mahlein 2023). The pathogen infects wheat during the flowering stage (anthesis), causing premature plant aging and shriveled grains. Infection also contaminates the harvest with mycotoxins such as deoxynivalenol (DON) and zearalenone, which pose serious health risks to humans and animals (Alisaac and Mahlein 2023). During later growth stages, periodic high humidity combined with canal irrigation can create conditions favorable to Fusarium species in Punjab.

Akbar et al. (2022) evaluated botanical extracts for FHB management in Pakistan and found that Melia azedarach extract at 50% concentration achieved 41.83% mycelial growth inhibition of F. graminearum in vitro, while Hibiscus rosa-chinensis and Cassia fistula extracts showed dose-dependent activity against the pathogen.

Kaur et al. (2024) demonstrated that a water-based extract of Acorus calamus significantly slowed fungal growth, achieving 78.73% inhibition at a concentration of 500 µg/mL. These findings are highly relevant to Punjab, where such plants are common agricultural by-products that could serve as low-cost management options for FHB.

2.4. Post-Harvest Grain Mold—Aspergillus flavus

Aspergillus flavus is one of the most consequential fungi responsible for grain contamination worldwide. It is a saprophytic mold that colonizes a wide variety of cereal crops and produces aflatoxins, a class of highly toxic secondary metabolites classified by the International Agency for Research on Cancer (IARC) as Group 1 human carcinogens (Ahmad et al. 2025). Chemically, aflatoxins are difuranocoumarin derivatives synthesized via the polyketide pathway; AFB1, AFB2, AFG1, and AFG2 represent the four primary forms (Balan et al. 2024).

Poor storage conditions facilitate the proliferation of A. flavus, making the mold difficult to manage. Fungal growth and toxin accumulation are favored when grain moisture exceeds 14%, or when storage temperature and relative humidity surpass 25°C (Gonda et al. 2024). Aflatoxin biosynthesis is highly temperature-sensitive, peaking between 28°C and 30°C but ceasing above 37°C (Wu et al. 2023). Under warm, humid storage conditions, aflatoxin B1 can accumulate rapidly, and if grain is left exposed under these conditions, toxin levels can exceed legal safety thresholds within 48 hours (Gonda et al. 2024).

3. Eco-Friendly and Sustainable Control Strategies

In Pakistan, farmers continue to rely predominantly on synthetic fungicides such as triazoles, strobilurins, propiconazole, azoxystrobin, and difenoconazole for disease control (Rehman et al. 2024). At the same time, rising concerns over fungicide resistance, chemical residues in grain, production costs, and environmental impact are driving demand for eco-friendly alternatives. This section reviews the leading sustainable strategies with demonstrated efficacy against the primary fungal pathogens affecting Punjab.

Table 2. Eco-friendly management strategies for fungal pathogens of wheat.

Strategy	Agent/Method	Target Pathogen	Efficacy (%)	Reference
Biocontrol – Bacteria	Bacillus subtilis	P. striiformis	91.9	Khan et al. (2023b)
Biocontrol – Bacteria	Bacillus velezensis	F. graminearum	55 (field)	Yeo et al. (2024)
Biocontrol – Fungi	Trichoderma harzianum (TH-5)	F. graminearum	40.33 (mycelial)	Kaur et al. (2024)
Biocontrol – Fungi	Curvularia lunata / A. fumigatus	P. striiformis	Significant	Khan et al. (2025)
Plant Extract	Melia azedarach (50%)	F. graminearum	41.83	Akbar et al. (2022)
Plant Extract	Acorus calamus (aqueous)	F. graminearum	78.73	Kaur et al. (2024)
Resistance Breeding	Gene pyramiding (Yr genes)	P. striiformis	Durable resistance	Dubekova et al. (2026)

Table 2. Eco-friendly management strategies for fungal pathogens of wheat.

Strategy	Agent/Method	Target Pathogen	Efficacy (%)	Reference
Biocontrol – Bacteria	Bacillus subtilis	P. striiformis	91.9	Khan et al. (2023b)
Biocontrol – Bacteria	Bacillus velezensis	F. graminearum	55 (field)	Yeo et al. (2024)
Biocontrol – Fungi	Trichoderma harzianum (TH-5)	F. graminearum	40.33 (mycelial)	Kaur et al. (2024)
Biocontrol – Fungi	Curvularia lunata / A. fumigatus	P. striiformis	Significant	Khan et al. (2025)
Plant Extract	Melia azedarach (50%)	F. graminearum	41.83	Akbar et al. (2022)
Plant Extract	Acorus calamus (aqueous)	F. graminearum	78.73	Kaur et al. (2024)
Resistance Breeding	Gene pyramiding (Yr genes)	P. striiformis	Durable resistance	Dubekova et al. (2026)

3.1. Biological Control Agents

3.1.1. Bacillus-Based Biocontrol

Among bacterial biocontrol agents, Bacillus subtilis has shown the highest efficacy against wheat stripe rust in Pakistan under field conditions.

Khan et al. (2023) demonstrated that combining Bacillus subtilis with plant defense activators achieved a 91.9% disease inhibition rate, outperforming the standard chemical treatment propiconazole, which achieved 89.3% inhibition. This finding positions B. subtilis as a promising alternative to synthetic fungicides for stripe rust management in the region.

The organism produces antifungal lipopeptides (iturin, surfactin, fengycin) that disrupt pathogen cell membranes and induce systemic resistance in host plants (Kashyap et al. 2025).

Yeo et al. (2024) reported that Bacillus velezensis JCK-7158 achieved 55% field control efficacy against Fusarium head blight in cereal crops. The strain exhibits a dual mechanism of action, directly antagonizing F. graminearum and upregulating host defense pathways (salicylic acid/jasmonic acid signaling), achieving a 40% reduction in nivalenol mycotoxin accumulation. Given the dual threat of yield loss and mycotoxin contamination posed by Fusarium species in Punjab, field validation of this approach under local environmental conditions is warranted.

3.1.2. Trichoderma-Based Biocontrol

Trichoderma harzianum and T. atroviride are among the most studied biocontrol fungi worldwide.

Kaur et al. (2024) demonstrated that T. harzianum (strain TH-5) achieved 40.33% mycelial growth inhibition of F. graminearum in vitro under dual-culture conditions.

The interaction between Trichoderma and F. graminearum is strain-dependent and involves both direct mycoparasitism and indirect mechanisms that alter primary and secondary metabolite biosynthesis in the pathogen (Özkale et al. 2023). In Pakistan, Trichoderma strains isolated from northwestern regions have shown antagonistic activity against multiple wheat pathogens (Anees et al. 2018).

3.1.3. Fungal Endophytes

Khan et al. (2025) investigated two indigenous fungal endophytes—Curvularia lunata (DT-40) and Aspergillus fumigatus (DT-8)—as biocontrol agents against wheat stripe rust across two susceptible cultivars. Both strains significantly improved wheat grain germination; in the 'Morocco' cultivar, DT-8 enhanced germination by 72.7%, improved plant growth by 55.6%, and increased seedling fresh weight by 110%. Both strains induced expression of secondary metabolites associated with host defense. This study is notable for evaluating locally isolated endophytic strains against a prevalent regional pathogen, Puccinia striiformis, providing regionally tailored biocontrol strategies.

3.2. Plant-Extract-Based Fungicides

Plant-derived fungicides represent a cost-effective, ecologically benign, and highly accessible alternative to synthetic agrochemicals, particularly for the resource-constrained smallholder farmers who constitute the majority of Punjab's wheat-producing sector.

Akbar et al. (2022) evaluated the antifungal efficacy of aqueous extracts from Melia azedarach (chinaberry), Hibiscus rosa-chinensis, and Cassia fistula against Fusarium graminearum. Among these, M. azedarach extract at 50% concentration exhibited the highest potency, inducing 41.83% inhibition of mycelial growth. This finding highlights the potential of a species widely distributed across the Punjab landscape.

Kaur et al. (2024) demonstrated that Acorus calamus aqueous extract achieved 78.73% inhibition of F. graminearum mycelial growth at 500 µg/mL, while an alcoholic extract provided complete inhibition at 400 µg/mL.

The methanolic extract of Zanthoxylum bungeanum, composed of flavonoids including quercetin, epicatechin, kaempferol-3-O-rhamnoside, and hyperoside, inhibited F. graminearum growth by up to 48.5% in vitro, reduced fungal DNA in wheat heads by 85.5%, and reduced DON mycotoxin production by 73% (Abbas and Yli-Mattila 2022). This study provides a strong scientific basis for developing locally sourced plant-extract formulations for Punjab farmers.

Essential oils have also been studied against fungal pathogens for their natural antifungal properties. Perczak et al. (2019) evaluated the efficacy of several essential oils—including oregano, cinnamon, palmarosa, verbena, orange, fennel, rosewood, and spearmint—against Fusarium culmorum and F. graminearum. Translating such findings into stable, field-ready products remains a critical research gap for Punjab's agricultural sector.

3.3. Host Resistance and Resistance Breeding

The development and deployment of genetically resistant wheat cultivars represents the most sustainable approach to managing fungal diseases in wheat, both financially and environmentally. Whereas chemical fungicides require repeated application and carry long-term ecological costs, resistant varieties offer a one-time investment with lasting returns for farmers. Pakistan has made notable progress in this area through collaboration between international and national research institutions.

Approximately 31 new wheat varieties have been released since 2021, comprising 30 bread wheat varieties and one durum wheat variety; 26 were developed using germplasm provided by the International Maize and Wheat Improvement Center (CIMMYT), reflecting the significance of international partnerships in national food security (CIMMYT 2023). Before release, these varieties underwent rigorous multi-year, multi-location field testing across Pakistan and demonstrated strong resistance to leaf and yellow rusts, tolerance to heat and drought stress, and compatibility with existing cropping systems in Punjab (Tiwari 2021). However, the rapid evolution of Puccinia strains through sexual recombination and somatic mutation continues to erode single major-gene resistance, underscoring the importance of durable, race-nonspecific resistance and gene-pyramiding approaches.

Virulence surveys across Pakistan have established that genes Yr3, Yr5, Yr10, Yr15, Yr26, YrSP, and YrCV remain effective against current Pst strains, whereas widely deployed genes Yr9, Yr27, and Yr17 have been overcome by virulent pathogen strains (Bux et al. 2012). For Southern Punjab varieties, field trials at MNSUAM Multan demonstrated differential responses among Galaxy-13, Sehar-06, and Ujala-16, with none showing complete immunity, underscoring the need for locally adapted multiline or blended varieties (Khan et al. 2023b). Combining adult-plant resistance genes such as Lr34/Yr18/Sr38 with seedling resistance genes through molecular marker-assisted selection represents the most promising pathway for durable protection (Sunilkumar et al. 2022).

4. Future Research Directions

Punjab is Pakistan's largest wheat-producing region; despite this, minimal progress has been made in addressing fungal disease challenges at the regional scale.

Population-level research on Puccinia striiformis, P. triticina, and Fusarium graminearum in Punjab remains rare, leaving insufficient data on pathogen evolution, fungicide-resistance alleles, and inter-regional strain migration. Similarly, mycotoxin monitoring (deoxynivalenol, aflatoxin B1, zearalenone) in Punjab's wheat grain is largely absent despite its direct relevance to food safety.

A second major gap lies between laboratory research and field reality. Biocontrol agents and botanical treatments have shown promising results under controlled conditions, but Punjab's variable rainfall, intense summer heat, and diverse soil types represent a markedly different environment. These strategies cannot be recommended to farmers without field validation under actual Punjab conditions.

Two directions stand out as priorities going forward. First, predictive disease modelling linking Punjab's shifting climate patterns to rust epidemic timing and Fusarium infection windows would provide a practical planning tool currently unavailable to researchers and farmers. Second, resistance-durability monitoring should become a structured, annual exercise embedded within Punjab's own institutions, tracking virulence shifts district by district before resistant varieties begin failing in farmers' fields. Both priorities require sustained funding and institutional commitment from universities and provincial agricultural bodies working in coordination.

5. Conclusion

Punjab is one of Pakistan's most critical wheat-producing regions, and its wheat sector faces a dynamic fungal disease landscape shaped by the combined pressures of climate change and evolving pathogen virulence. This review has documented that stripe rust (P. striiformis f. sp. tritici), leaf rust (P. triticina), Fusarium head blight (F. graminearum), and grain mold (A. flavus) collectively threaten grain yield, quality, and food safety across the region. Punjab's agro-climatic conditions—rising temperatures, declining rainfall, and episodic humidity—are increasingly shifting disease dynamics in ways that demand updated management responses.

Eco-friendly control strategies, particularly Bacillus subtilis-based biocontrol (91.9% suppression of stripe rust), Trichoderma harzianum against Fusarium, botanical extracts of Melia azedarach and Acorus calamus, and endophytic fungal biocontrol agents offer scientifically validated and locally applicable alternatives to synthetic fungicides. Host resistance through gene pyramiding (Yr3, Yr5, Yr10, Yr15, Yr26) remains the most durable long-term solution. Addressing the research priorities identified in this review—regional pathogen genomics, mycotoxin surveillance, multi-season field trials of eco-friendly strategies, and climate-disease modelling—will be essential to safeguarding food security in one of Pakistan's most agriculturally productive regions.