The study, conducted by Yuejin Peng, Qingqing Liu, Yangshan Hu, Junmin Liang, Ziqian Yang and Lujia Yang, and published in BMC Plant Biology, focused on two fungal isolates recovered from maize: Purpureocillium lilacinum strain PL6 and Beauveria bassiana strain YC-1. Both species are well known in agricultural circles, particularly Beauveria bassiana, which has a long history as an insect-killing fungus used in biological pest control. What makes the new work notable is the combination of approaches the team brought to bear. Rather than simply testing whether the fungi could fight rust, the researchers combined morphological observation, molecular phylogenetic identification, whole-genome sequencing, laboratory bioassays and insect pathogenicity tests to build a comprehensive picture of what these organisms are and what they can do.

The genomic work formed the technical backbone of the study. Using Illumina sequencing, the team assembled draft genomes of 36.68 megabases for PL6 and 33.05 megabases for YC-1. These genome sequences allowed the researchers to peer into the genetic machinery that might underpin the fungi’s beneficial properties. Annotation with the dbCAN3 pipeline, a standard tool for identifying genes encoding carbohydrate-active enzymes, revealed 187 such genes in PL6 and 137 in YC-1. Carbohydrate-active enzymes, often abbreviated as CAZymes, are proteins that break down or modify complex carbohydrates, and in plant-associated fungi they are frequently involved in colonizing plant tissue, degrading pathogen cell walls, or establishing endophytic lifestyles within host plants.

Perhaps even more intriguing were the secondary metabolite biosynthesis gene clusters predicted by the antiSMASH algorithm. The analysis identified 34 such clusters in PL6 and 32 in YC-1, including clusters associated with polyketide synthases, nonribosomal peptide synthetases and terpene biosynthesis. These gene families are responsible for producing some of the most biologically active natural compounds known to science, including antibiotics, toxins and signaling molecules. In biocontrol fungi, secondary metabolites often serve as the chemical weapons that suppress competing pathogens or subvert insect hosts. The abundance and diversity of these clusters in both strains suggests a rich reservoir of unexplored chemistry that could be harnessed for agricultural applications, and it gives researchers a genetic roadmap for future work on identifying the specific compounds involved.

The greenhouse-scale bioassays delivered the headline results. The researchers applied the fungi through root-drench inoculation, a delivery method in which a liquid suspension of the beneficial fungus is applied to the soil around the plant roots, allowing the endophyte to colonize the plant from within. Under the controlled conditions used in the study, both strains restricted the development of southern corn rust. At 24 days post-inoculation, disease incidence remained below 4 percent in plants treated with PL6, while plants treated with YC-1 showed disease incidence of approximately 21 percent. In the untreated control group, by contrast, nearly 48 percent of plants had developed the disease by the same time point.

To quantify disease progression more rigorously, the team calculated the area under the disease progress curve, or AUDPC, a standard epidemiological measure that integrates disease severity over time rather than relying on a single snapshot. The AUDPC dropped from 87.12 in the untreated control to 20.92 following YC-1 treatment and 10.58 following PL6 treatment. Those figures translate into reductions of 76.0 percent and 87.9 percent respectively, a striking level of protection for a disease that typically demands repeated fungicide applications. The magnitude of the PL6 effect in particular suggests that this strain could be a serious candidate for development as a commercial biocontrol agent, although the authors are careful to note that the results come from controlled conditions and that field performance remains to be demonstrated.

What elevates the study beyond a straightforward disease-suppression trial is its dual-purpose angle. Because Beauveria bassiana is already celebrated as an entomopathogenic fungus, the researchers also tested whether their isolates could attack insect pests, specifically fifth-instar larvae of Spodoptera frugiperda, the fall armyworm, another globally feared maize pest. In 10-day bioassays, larval survival was approximately 73 percent with YC-1 and 83 percent with PL6, corresponding to mortality of roughly 27 percent and 17 percent respectively. YC-1, as expected for a species with a strong entomopathogenic pedigree, proved the more lethal of the two against the caterpillars, while PL6 was clearly the stronger rust suppressor. The finding that a single fungal resource could contribute to managing both a foliar rust disease and a lepidopteran pest is precisely the kind of multifunctionality that integrated pest management programs prize.

The concept of endophyte-mediated biocontrol is gaining momentum across plant pathology. Endophytic fungi inhabit the internal tissues of plants, often without causing any symptoms, and in many cases they confer benefits to their hosts, ranging from enhanced stress tolerance to induced systemic resistance against pathogens. When an endophyte establishes itself inside a plant, it can prime the plant’s own defense signaling pathways, including those mediated by salicylic acid and jasmonic acid, two key hormones in plant immunity. It can also compete directly with pathogens for space and resources, or produce antimicrobial compounds in situ. The rich arsenal of secondary metabolite gene clusters documented in PL6 and YC-1 hints that such chemical warfare may be part of the mechanism at work, though the study’s genomic characterization stops short of confirming which specific compounds are deployed during rust suppression.

The implications for maize farming could be significant. Southern corn rust has been expanding its reach in recent years, aided by warming climates and long-distance spore dispersal, and growers in affected regions often face the prospect of multiple fungicide sprays per season. A biological approach based on root-drench inoculation with endophytic fungi could reduce that chemical load, fit neatly into organic and low-input production systems, and offer a tool against fall armyworm at the same time. The genome-reported nature of the two strains is also an asset for regulatory and development pipelines, because whole-genome sequences help clarify strain identity, screen for unwanted virulence or toxin genes, and support quality control in commercial production. The work was supported by the National Natural Science Foundation of China, the Natural Science Foundation of Yunnan Province and the Yunnan Provincial Department of Education Scientific Research Fund Project.

There remain important caveats and next steps. The disease and insect assays were performed under controlled laboratory and greenhouse conditions, and real-world fields present far more variable environments, competing microbes, and pathogen pressures. The moderate insect mortality observed, particularly for PL6, suggests these strains would likely serve as components of an integrated management strategy rather than stand-alone silver bullets. Nevertheless, the combination of strong rust suppression, documented genomes, abundant biosynthetic potential and demonstrated activity against a major pest makes PL6 and YC-1 a compelling proof of concept. As agriculture searches for ways to sustain productivity while weaning itself off synthetic chemistry, studies like this one show that the answers may already be living inside the crops themselves, waiting to be sequenced, understood and deployed.

Subject of Research: Genomic characterization of endophytic fungi as biocontrol agents against southern corn rust and fall armyworm in maize

Article Title: Genomic characterization and biocontrol potential of the endophytic Purpureocillium lilacinum PL6 and Beauveria bassiana YC-1 against southern corn rust

Article References: Peng, Y., Liu, Q., Hu, Y., Liang, J., Yang, Z., & Yang, L. (2026). Genomic characterization and biocontrol potential of the endophytic Purpureocillium lilacinum PL6 and Beauveria bassiana YC-1 against southern corn rust. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10090-y

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10090-y

Keywords: Purpureocillium lilacinum, Beauveria bassiana, southern corn rust, Puccinia polysora, endophytic fungi, biological control, maize, whole-genome sequencing, secondary metabolites, Spodoptera frugiperda, fall armyworm, plant pathology

Researchers at Ladoke Akintola University of Technology in Ogbomoso evaluated 32 maize hybrids, including 26 experimental top-cross hybrids developed by the Maize Improvement Programme of the International Institute of Tropical Agriculture and six commercial checks, across two planting dates in the 2024 season. The trials were deliberately left exposed to natural fall armyworm infestation, and the plants received no insecticide against the pest. The team scored foliar damage at four, eight, and twelve weeks after sowing using a modified Davis rating scale, alongside a full suite of agronomic measurements from flowering time to husk cover, plant height, and grain yield adjusted to standard moisture.

The standout performer was hybrid G1, bred from the cross FAWSYN-1/(TZLComp. 1 C6-W-39-1-1)-B-B, which produced 5,223.3 kilograms of grain per hectare across environments, a 26.8 percent yield advantage over the best commercial check, Oba Super 9. Roughly 30.7 percent of the tested hybrids outyielded that top check, and eight of the 26 experimental hybrids beat all six commercial controls. The new hybrids also showed improvements of 9 to 13 percent in husk cover, plant aspect, and ear aspect ratings, 5 to 12 percent better tolerance of southern corn leaf blight and ear rot, and 12 to 35 percent improved tolerance of foliar fall armyworm damage across the scoring intervals.

The statistical architecture of the trial revealed as much about the environment as about the genetics. Analysis of variance showed highly significant differences among hybrids, environments, and their interactions for grain yield and most agronomic traits. When the total variation in grain yield was partitioned, the environment accounted for 54 percent, hybrids for 21 percent, and the hybrid-by-environment interaction for 11 percent. In other words, where and when the maize grew mattered more than which hybrid was in the ground, a sobering reminder of how strongly rain-fed African farming systems are governed by weather. The two planting dates produced dramatically different outcomes: grain yield ranged from 715.4 to 3,241.2 kilograms per hectare in the early planting, but from 901.8 to 7,205.3 kilograms per hectare in the later sowing, a gap of more than 2,300 kilograms per hectare between environment means.

The reason for that gap lay in the rainfall record. A prolonged drought between July and August struck the later-planted crop during the critical periods before anthesis and after silking, stretching the anthesis-silking interval from one or two days in the first environment to three to seven days in the second. Maize is notoriously sensitive to moisture stress during flowering and grain filling, and the combined burden of drought and heavy fall armyworm pressure drove yields down in the first planting. The authors note that erratic rainfall, including a cessation of rain after planting that stressed seedlings and excessive rain near maturity that caused lodging, complicated the evaluation, yet the pest pressure remained sufficient to differentiate the hybrids consistently.

Correlation and regression analyses pinpointed which traits actually mattered for yield under pest attack. Grain yield correlated significantly and negatively with foliar fall armyworm damage, plant aspect, and husk cover ratings, meaning that hybrids with cleaner leaves, more compact and appealing plant architecture, and tighter husk coverage yielded more. Plant aspect showed the strongest individual association with yield, explaining 42 percent of its variability in regression analysis, with each unit worsening in the score costing roughly 1,402 kilograms per hectare. Foliar armyworm damage itself explained 13 percent of yield variation, and every unit increase in the damage score reduced grain yield by about 864 kilograms per hectare. Plant height and ear height, by contrast, correlated positively with yield, reflecting the larger leaf area and photosynthetic capacity of taller plants.

The genetic analysis added an important caveat. Broad-sense heritability was moderate for flowering traits and foliar diseases, ranging from 42 to 55 percent, but low, between 3 and 13 percent, for grain yield and fall armyworm damage scores. Environmental variance exceeded genetic variance for every trait measured, and genotypic coefficients of variation were consistently lower than phenotypic ones. This means that much of what breeders observe in any single season reflects the environment rather than stable genetic differences, and the authors caution that these estimates are population- and environment-specific, requiring validation across additional locations and years before broader breeding inferences can be drawn.

To cut through the complexity of selecting for many traits at once, the team applied the genotype by yield times trait biplot, a multivariate technique that ranks hybrids by how well they combine grain yield with each desirable characteristic. The first two principal components captured about 82 percent of the variation, and the analysis identified five hybrids, G1, G9, G21, G18, and G3, as superior combinations of high yield and moderate fall armyworm tolerance. Hybrid G1 and its close relative G9 excelled at pairing yield with low ear rot and Curvularia leaf spot scores, while G21 and G18 combined yield with strong rust tolerance and favorable plant and ear aspects. The same analysis flagged the weakest performers, including the commercial hybrid Oba Super 2, which yielded only 1,502.7 kilograms per hectare.

Notably, the commercial checks revealed how far standard market varieties still lag. Most checks showed consistent baseline susceptibility to fall armyworm, with several leaves bearing holes and lesions across the scoring weeks, while two experimental hybrids, G7 and G19, maintained low, stable damage ratings throughout the season. Among the commercial options, only SAMMAZ 51 stood out as an outlier with meaningful tolerance. The mean damage ratings of all top-cross hybrids stayed below 6 on the nine-point scale, and scores generally declined as plants matured, consistent with earlier reports that infestation pressure eases with crop age.

The study, published in Discover Plants, stops short of recommending the hybrids to farmers just yet. The authors emphasize that the five promising candidates must now advance to multi-location, multi-year uniform yield trials to confirm their adaptation and stability across the derived savanna agroecology and beyond. Still, the findings carry weight for a region where Nigerian farmers harvest an average of just 2.2 tonnes of maize per hectare against a global average of 4.5 tonnes. Host plant resistance, which works through antixenosis, antibiosis, and tolerance, imposes minimal selection pressure on pest populations and, integrated with biological and cultural controls, offers a durable, environmentally safe, and affordable line of defense. In a warming, pest-threatened world, breeding resilience directly into the seed may prove one of the most powerful tools African agriculture has.

Subject of Research: Phenotypic evaluation of fall armyworm-resistant top-cross maize hybrids under rain-fed conditions in a derived savanna agroecology

Article Title: Variation in the phenotypic performance of top-cross fall armyworm resistant maize hybrids under rain-fed growing conditions in a derived savanna agroecology

Article References: Olayinka, A. O., Odewole, A. F., Akande, O. S., Adebayo, P. A., & Ujah, G. O. (2026). Variation in the phenotypic performance of top-cross fall armyworm resistant maize hybrids under rain-fed growing conditions in a derived savanna agroecology. Discover Plants, 3(1), Article 424. https://doi.org/10.1007/s44372-026-00896-3

Image Credits: AI Generated

DOI: 10.1007/s44372-026-00896-3

Keywords: fall armyworm, maize hybrids, host plant resistance, grain yield, derived savanna, Nigeria, plant breeding, GYT biplot, heritability, genotype by environment interaction, Spodoptera frugiperda, food security

The study, published in the journal Acta Parasitologica, was conducted by Akshay Majare, Nandkishore Lavhe, V. K. Biradar and Tini Pillai of the College of Agriculture in Nagpur, together with colleagues at the ICAR–Central Institute for Cotton Research and the ICAR–Central Potato Research Institute. The researchers set out to answer two questions that matter enormously for anyone designing integrated pest management programmes. First, how lethal are two species of entomopathogenic nematodes, Steinernema siamkayai and Heterorhabditis indica, against third-instar fall armyworm larvae? Second, are these nematodes compatible with two commercially important entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, and does the answer depend on whether the organisms are applied together or one after the other?

Entomopathogenic nematodes are microscopic roundworms that hunt insect larvae in the soil. Their infective juveniles, the free-living stage used in biocontrol, carry symbiotic bacteria in their guts. When a nematode enters an insect through natural openings such as the mouth, spiracles or anus, it releases these bacteria into the haemocoel, the insect’s open circulatory cavity. The bacteria multiply rapidly, killing the host within days through septicaemia and providing the nematodes with a nutrient-rich environment in which to reproduce. Entomopathogenic fungi attack by a different route: spores germinate on the insect’s cuticle, penetrate the body wall, and proliferate internally, eventually killing the host and sporulating on its corpse. Because the two agents exploit different infection pathways and different ecological niches, scientists have long suspected that combining them could deliver a one-two punch that neither achieves alone.

To test this, the team first measured the inherent virulence of each nematode species under controlled laboratory conditions. Third-instar fall armyworm larvae were exposed to a range of infective juvenile concentrations, from five to one hundred nematodes per larva, and mortality was recorded over ninety-six hours. The results were strikingly asymmetric. Steinernema siamkayai proved consistently and substantially more virulent than Heterorhabditis indica. At doses of thirty to forty infective juveniles per larva, S. siamkayai achieved complete mortality of the test larvae within ninety-six hours, whereas H. indica required the full one hundred juveniles per larva to reach the same endpoint. Probit analysis, a standard statistical technique for quantifying dose-response relationships in toxicology, confirmed the gap: the lethal concentration needed to kill half the larvae, the LC50, was just 5.47 infective juveniles per larva for S. siamkayai, compared with 15.14 for H. indica. The LC90 values told an even starker story, at 14.23 versus 83.52 infective juveniles per larva respectively. In practical terms, the Steinernema species needed roughly one-sixth the dose of its Heterorhabditis counterpart to achieve near-total kill.

With virulence baselines established, the researchers turned to the compatibility question. They paired each nematode with each fungus in three application regimes: simultaneous inoculation, nematode applied first followed by fungus, and fungus applied first followed by nematode. Larval mortality was recorded, and the interactions were classified using co-toxicity factor analysis, a method borrowed from pesticide combination studies that quantifies whether two agents act additively, synergistically or antagonistically when combined. The outcome hinged almost entirely on the nematode species involved. Simultaneous application of any nematode-fungus pair produced additive interactions across the board, meaning the combined mortality matched what would be expected from the sum of the individual effects, with no interference between the agents. The standout combination was S. siamkayai together with Metarhizium anisopliae, which killed 98.55 percent of larvae at ninety-six hours, the highest figure recorded in the laboratory phase of the study.

The picture changed, however, when the agents were applied sequentially. When Heterorhabditis indica was introduced after the fungi had already been applied, the interaction turned antagonistic: the combined mortality fell short of expectations, suggesting that the fungus, by establishing itself in or on the host first, somehow compromised the nematode’s ability to infect or complete its development. The authors did not identify the precise mechanism in this study, but the phenomenon is consistent with competition for the host resource. Both agents ultimately depend on the same larval cadaver for reproduction, and a fungus that has colonised a host first may leave insufficient resources, or an unsuitable internal environment, for the nematode’s symbiotic bacteria to flourish. Notably, Steinernema siamkayai was immune to this sequencing effect, maintaining additive compatibility with both fungi regardless of whether it was applied before or after them. This robustness marks it out as the more dependable partner in a combined biocontrol programme.

To check that the laboratory findings survived contact with more realistic conditions, the team validated the most promising combinations in pot experiments, with mortality and co-toxicity factors assessed at one hundred and twenty hours after treatment. Alone, S. siamkayai caused the highest larval mortality at 80.3 percent, followed by H. indica at 70.5 percent. Among the combined treatments, S. siamkayai plus M. anisopliae again led the field, achieving 71.5 percent mortality, and every nematode-fungus combination tested in pots registered additive interactions by co-toxicity analysis. The somewhat lower figures under pot conditions compared with the laboratory are unsurprising, since soil structure, moisture and other environmental variables inevitably dilute infection efficiency, but the qualitative conclusion held: simultaneous application preserves compatibility, and S. siamkayai is the more forgiving and more lethal of the two nematodes.

The significance of these results extends beyond a single pest. Fall armyworm management currently leans heavily on synthetic insecticides and Bt-transgenic crops, both of which face mounting resistance problems. Field populations of the pest have already shown multiple and cross-resistance to Bt toxins and organophosphates in some regions, and the caterpillar’s polyphagous habits, documented across dozens of host plant species in the Americas, make crop rotation alone an inadequate defence. Microbial biocontrol agents offer a complementary tool that is difficult for pests to circumvent, because the selection pressures they impose differ fundamentally from those of chemical toxins. Moreover, entomopathogenic nematodes and fungi are self-replicating, leave no toxic residues, and are compatible with many other components of integrated pest management, including certain insecticides, as earlier studies on their chemical compatibility have shown.

What this study adds is a practical rule of thumb for deploying such agents together. Compatibility between biocontrol agents is often assumed rather than tested, and the assumption can be costly. Prior research has documented both synergy and antagonism in nematode-fungus combinations against other pests, including black vine weevil, wireworms and scarab grubs, and the mechanisms underlying these interactions, from volatile organic compounds emitted by fungi that influence nematode foraging to direct competition for the host cadaver, remain an active area of investigation. By demonstrating that application sequence is a decisive variable for H. indica but not for S. siamkayai, the Indian team has given practitioners a concrete, testable guideline: if in doubt, apply simultaneously, and if a sequential schedule is unavoidable, choose the nematode species that tolerates it.

The authors identify S. siamkayai, particularly in combination with Metarhizium anisopliae, as a promising microbial strategy for the integrated management of fall armyworm. Field-scale trials will be needed to confirm that the additive interactions observed in the laboratory and in pots translate into meaningful yield protection in farmers’ fields, where UV radiation, desiccation and soil heterogeneity all challenge the survival of both agents. But the core message is already actionable. In the escalating contest between growers and one of the world’s most adaptable crop pests, the details of biological control matter, and something as mundane as the order of two spray applications may be the difference between a partnership that works and one that quietly undermines itself.

Subject of Research: Compatibility and virulence of entomopathogenic nematodes and fungi against the fall armyworm Spodoptera frugiperda

Article Title: Application Sequence Determines the Compatibility and Virulence of Entomopathogenic Nematodes and Entomopathogenic Fungi Against Spodoptera frugiperda

Article References: Majare, A., Lavhe, N., Biradar, V. K., Pillai, T., Deshmukh, V., Banu, G., Fand, B. B., Shah, V., Mhatre, P. H., & Thube, S. (2026). Application Sequence Determines the Compatibility and Virulence of Entomopathogenic Nematodes and Entomopathogenic Fungi Against Spodoptera frugiperda. Acta Parasitologica, 71(5), Article 220. https://doi.org/10.1007/s11686-026-01406-x

Image Credits: AI Generated

DOI: 10.1007/s11686-026-01406-x

Keywords: fall armyworm, Spodoptera frugiperda, entomopathogenic nematodes, entomopathogenic fungi, Steinernema siamkayai, Heterorhabditis indica, Metarhizium anisopliae, Beauveria bassiana, biological control, application sequence, co-toxicity factor, integrated pest management