Spore Dispersal Research Articles

The evolution of reproductive leaf dimorphism in two globally distributed fern families is neither stepwise nor irreversible, unless further specialization evolves.

A contemporary interpretation of Dollo's Law is that the evolution of specialized structures is irreversible. Among land plants, reproductive specialization shows a trend toward increasing complexity without reversion, raising questions about evolutionary steps and irreversibility of reproductive complexity. Ferns, exhibit varied reproductive strategies, some are dimorphic (producing separate leaves for photosynthesis and reproduction), while others are monomorphic (where one leaf is used for both photosynthesis and spore dispersal). This diversity provides an opportunity to examine the applicability of Dollo's Law in the evolution of reproductive leaf specialization across plants. We analyzed 118 species in Blechnaceae and Onocleaceae using quantitative morphometrics and phylogenetic comparative methods to test the pillars of Dollo's Law of irreversibility. The evolution of dimorphism in Blechnaceae is neither stepwise nor irreversible, with direct transitions from monomorphism to dimorphism, including several reversions. In contrast, Onocleaceae exhibit irreversibility to monomorphism upon further specialization of fertile leaves for spore dispersal, suggesting that additional specialization, not dimorphism alone, may facilitate irreversibility. These results provide insight into the canalization of fertile-sterile leaf dimorphism in seed plants, where traits like heterospory and ovules lead to further specialization and potential irreversibility. These findings suggest that as new specialized traits evolve alongside pre-existing ones, reversion may become increasingly unlikely.

Field-scale gene flow of fungicide resistance in Pyrenophora teres f. teres and the effect of selection pressure on the population structure.

The effectiveness of fungicides to control foliar fungal crop diseases is being diminished by the increasing spread of resistances to fungicides. One approach that may help to maintain efficacy is remediation of resistant populations by sensitive ones. However, the success of such approaches can be compromised by re-incursion of resistance through aerial spore dispersal; although, knowledge of localized gene flow is lacking. Here, we report on a replicated mark-release-recapture field experiment with several treatments set up to study spore-dispersal-mediated gene flow of a mutated allele that confers demethylase inhibitor resistance in Pyrenophora teres f. teres (Ptt). Artificial inoculation of the host, barley (Hordeum vulgare), was successful across the 12-ha trial, where the introduced sensitive- and resistant-populations were, respectively, 6- and 13-fold the DNA concentration of the native Ptt population. Subsequent disease pressure remained low which hampered spread of the epidemic to such extent that gene flow was not detected at, or beyond 2.5 m from source points. In the absence of gene flow, plots were assessed for treatment effects; fungicide applied to populations that contained 14.3% of allele mutation increased in frequency to 24.5%, whereas sensitive populations had no change in structure. Untreated controls of native Ptt population remained genetically stable, yet untreated controls that were inoculated with sensitive Ptt had half the resistance frequency of the native population structure. The trial demonstrates the potential for management to remediate fungicide resistant pathogen populations, where localized gene flow is minimal; to safeguard chemical crop protection into the future.

Moss spores: overlooked airborne bioparticles in an urban environment.

Moss spores are present in aerobiological samples, but their low representation, lack of known allergenic properties, and difficult identification have led to their being overlooked by aerobiologists so far. The data about their presence in the atmosphere and the factors that influence them are, however, important from the biodiversity conservation point of view, since they give us information about their ability to spread to new habitats. In this pilot study, we analysed their presence in the atmosphere of Bratislava city, Slovakia (2018-2023), using Burkard volumetric sampler, and determined the most significant factors influencing its temporal distribution. The size category of 13-18 µm was the most represented in the samples. Environmental factors influenced the daily spore concentrations and the characteristics of the whole spore season. The start of the Main Spore Season (MSS) depended mainly on the temperatures in November-January, initiating earlier growth of sporophytes in the following year, while the intensity of the MSS was influenced by high humidity in April, stimulating the formation of spores in sporangia. The daily concentration of airborne moss spores was mostly influenced by the actual temperature and wind speed, promoting the release and dispersal of spores, and precipitation lowering their levels due to the "wash-out" effect, although no intradiurnal pattern was observed. More data from other locations is needed to determine the role of atmospheric spore transport for the conservation of moss species facing anthropogenic climatic change.

Developing Predictive Models and Early Warning Systems for Invading Pathogens: Wheat Rusts.

Innovations in aerobiological and epidemiological modeling are enabling the development of powerful techniques to infer connectivity networks for transboundary pathogens in ways that were not previously possible. The innovations are supported by improved access to historical and near real-time highly resolved weather data, multi-country disease surveillance data, and enhanced computing power. Using wheat rusts as an exemplar, we introduce a flexible modeling framework to identify characteristic pathways for long-distance spore dispersal within countries and beyond national borders. We show how the models are used for near real-time early warning systems to support smallholder farmers in East Africa and South Asia. Wheat rust pathogens are ideal exemplars because they continue to pose threats to food security, especially in regions of the world where resources for control are limited. The risks are exacerbated by the rapid appearance and spread of new pathogenic strains, prodigious spore production, and long-distance dispersal for transboundary and pandemic spread.

Designing of nematode egg parasitic fungus, Purpureocillium lilacinum, nanoemulsion for management of Meloidogyne incognita infection in tomato

Summary Purpureocillium lilacinum is a potent biocontrol agent against Meloidogyne spp. and various other plant-parasitic nematodes in crops. However, existing commercial formulations of P. lilacinum suffer from drawbacks like short shelf life and inconsistent performance in different environmental conditions. To address these issues, a new nano-formulation of P. lilacinum was developed and tested against Meloidogyne incognita infecting tomatoes. Initially, edible oil-based emulsions were prepared using probe ultrasonication, with 40 formulations screened and 14 selected for further testing. Seven of these emulsions remained stable at room temperature (28 ± 4°C) for 8 weeks, with stability assessed based on particle size, zeta potential, and particle shape using particle size analysis and transmission electron microscopy (TEM). Among these, NE 8 (comprising 10 ml of 1% carboxyl methyl cellulose (CMC), 1.25 ml of Tween 80 and 5 ml of sunflower oil) exhibited superior characteristics, with an average particle size of 226.6 nm, a zeta potential of −54.80 mV, and a spherical morphology under TEM examination. The P. lilacinum nanoemulsion formulation was produced by homogenising NE 8 emulsion and spores at a 1:1 ratio, ensuring efficient spore dispersion and encapsulation without loss of viability. In vitro tests demonstrated 100% immobility of M. incognita second-stage juveniles (J2) and 100% parasitism of eggs at a concentration of 5.0 ml l−1. Under glasshouse conditions, soil drenching with the nano-formulation at concentrations ranging from 0.5 to 5.0 ml l−1 resulted in enhanced tomato growth and significant suppression of M. incognita populations in soil and roots, with increased egg mass parasitism. Bio-safety tests confirmed that P. lilacinum nano-formulation at concentrations of 0.25 ml l−1 and 5.0 ml l−1 had no harmful effects on the earthworm Eudrilus eugeniae.

Adaptation of Fusarium Head Blight Pathogens to Changes in Agricultural Practices and Human Migration.

Fusarium head blight (FHB) is one of the most destructive wheat diseases worldwide. To understand the impact of human migration and changes in agricultural practices on crop pathogens, here population genomic analysis with 245 representative strains from a collection of 4,427 field isolates of Fusarium asiaticum, the causal agent of FHB in Southern China is conducted. Three populations with distinct evolution trajectories are identifies over the last 10,000 years that can be correlated with historically documented changes in agricultural practices due to human migration caused by the Southern Expeditions during the Jin Dynasty. The gradual decrease of 3ADON-producing isolates from north to south along with the population structure and spore dispersal patterns shows the long-distance (>250km) dispersal of F. asiaticum. These insights into population dynamics and evolutionary history of FHB pathogens are corroborated by a genome-wide analysis with strains originating from Japan, South America, and the USA, confirming the adaptation of FHB pathogens to cropping systems and human migration.

Bimodal spore release heights in the water column enhance local retention and population connectivity of bull kelp, Nereocystis luetkeana.

Dispersal of reproductive propagules determines recruitment patterns and connectivity among populations and can influence how populations respond to major disturbance events. Dispersal distributions can depend on propagule release strategies. For instance, the bull kelp, Nereocystis luetkeana, can release propagules (spores) from two heights in the water column ("bimodal release"): at the water surface, directly from the reproductive tissues (sori) on the kelp's blades, and near the seafloor after the sori abscise and sink through the water column. N. luetkeana is a foundation species that occurs from central California to Alaska and is experiencing unprecedented levels of population declines near its southern range limit. We know little of the kelp's dispersal distributions, which could influence population recovery and restoration. Here, we quantify how bimodal spore release heights affect dispersal outcomes based on a numerical model specifically designed for N. luetkeana. The model incorporates oceanographic conditions typical of the species' coastal range and kelp biological traits. With bimodal release heights, 34% of spores are predicted to settle within 10 m of the parental alga and 60% are predicted to disperse beyond 100 m. As an annual species, bimodal release heights can facilitate the local regeneration of adults within a source kelp forest while also supporting connectivity among multiple forests within broader bull kelp metapopulations. To leverage this pattern of bimodal spore dispersal in bull kelp restoration management, directing resources toward strategically located focal populations that can seed other ones could amplify the scale of recovery.

Fluid Ejections in Nature.

From microscopic fungi to colossal whales, fluid ejections are universal and intricate phenomena in biology, serving vital functions such as animal excretion, venom spraying, prey hunting, spore dispersal, and plant guttation. This review delves into the complex fluid physics of ejections across various scales, exploring both muscle-powered active systems and passive mechanisms driven by gravity or osmosis. It introduces a framework using dimensionless numbers to delineate transitions from dripping to jetting and elucidate the governing forces. Highlighting the understudied area of complex fluid ejections, this review not only rationalizes the biophysics involved but also uncovers potential engineering applications in soft robotics, additive manufacturing, and drug delivery. By bridging biomechanics, the physics of living systems, and fluid dynamics, this review offers valuable insights into the diverse world of fluid ejections and paves the way for future bioinspired research across the spectrum of life.

A description of two novel Psilocybe species from southern Africa and some notes on African traditional hallucinogenic mushroom use

ABSTRACT Two new Psilocybe species (Hymenogastraceae), P. ingeli and P. maluti, are described from southern Africa. Morphology and phylogeny were used to separate the two novel fungi from their closest relatives in the genus. Psilocybe ingeli was found fruiting on bovine manure–enriched grasslands in the Kwa-Zulu Natal Province of South Africa and differs from its closest relative P. keralensis and others in the internal transcribed spacer ITS1-5.8S-ITS2, partial 28S nuc rDNA, and translation elongation factor 1-alpha regions, distribution, and having larger basidiospores. Similarly, P. maluti was collected from the Free State Province of South Africa and observed in the Kingdom of Lesotho, growing on bovine manure. A secotioid pileus, geographic distribution, and differences in the same DNA regions distinguish P. maluti from its closest relative P. chuxiongensis. Furthermore, the spore dispersal and traditional, spiritualistic use of P. maluti are discussed here.

Extreme functional specialization of fertile leaves in a widespread fern species and its implications on the evolution of reproductive dimorphism.

Resource allocation theory posits that organisms distribute limited resources across functions to maximize their overall fitness. In plants, the allocation of resources among maintenance, reproduction, and growth influences short-term economics and long-term evolutionary processes, especially during resource scarcity. The evolution of specialized structures to divide labor between reproduction and growth can create a feedback loop where selection can act on individual organs, further increasing specializaton and resource allocation. Ferns exhibit diverse reproductive strategies, including dimorphism, where leaves can either be sterile (only for photosynthesis) or fertile (for spore dispersal). This dimorphism is similar to processes in seed plants (e.g., the production of fertile flowers and sterile leaves), and presents an opportunity to investigate divergent resource allocation between reproductive and vegetative functions in specialized organs. Here, we conducted anatomical and hydraulic analyses on Onoclea sensibilis L., a widespread dimorphic fern species, to reveal significant structural and hydraulic divergences between fertile and sterile leaves. Fertile fronds invest less in hydraulic architecture, with nearly 1.5 times fewer water-conducting cells and a nearly 0.5 times less drought-resistant xylem compared to sterile fronds. This comes at the increased relative investment in structural support, which may help facilitate spore dispersal. These findings suggest that specialization in ferns-in the form of reproductive dimorphism-can enable independent selection pressures on each leaf type, potentially optimizing spore dispersal in fertile fronds and photosynthetic efficiency in sterile fronds. Overall, our study sheds light on the evolutionary implications of functional specialization and highlights the importance of reproductive strategies in shaping plant fitness and evolution.

A Simulation Study to Reveal the Epidemiology and Aerosol Transmission Characteristics of Botrytis cinerea in Grape Greenhouses.

Most previously studies had considered that plant fungal disease spread widely and quickly by airborne fungi spore. However, little is known about the release dynamics, aerodynamic diameter, and pathogenicity threshold of fungi spore in air of the greenhouse environment. Grape gray mold is caused by Botrytis cinerea; the disease spreads in greenhouses by spores in the air and the spore attaches to the leaf and infects plant through the orifice. In this study, 120 μmol/L propidium monoazide (PMA) were suitable for treatment and quantitation viable spore by quantitative real-time PCR, with a limit detection of 8 spores/mL in spore suspension. In total, 93 strains of B. cinerea with high pathogenicity were isolated and identified from the air samples of grapevines greenhouses by a portable sampler. The particle size of B. cinerea aerosol ranged predominately from 0.65-3.3 μm, accounting for 71.77% of the total amount. The B. cinerea spore aerosols were infective to healthy grape plants, with the lowest concentration that could cause disease being 42 spores/m3. Botrytis cinerea spores collected form six greenhouse in Shandong Province were quantified by PMA-qPCR, with a higher concentration (1182.89 spores/m3) in May and June and a lower concentration in July and August (6.30 spores/m3). This study suggested that spore dispersal in aerosol is an important route for the epidemiology of plant fungal disease, and these data will contribute to the development of new strategies for the effective alleviation and control of plant diseases.

Fungi: friends or foes-an outreach science initiative for the collection of airborne fungal spores by high school students.

Fungi mostly reproduce through spores that are adapted for airborne dispersal; hence, fungal spores (and fungi) are found virtually everywhere. Fungi can be "friends or foes." Our friends include fungi used in the food and biotech industries, fungi that contribute to the cycling of carbon and nutrients, and those involved in the decontamination of polluted soils and/or water, to mention just a few examples. Many species, however, are foes-they are detrimental to plants, animals, and/or humans. Annually, >1.5 million people die due to invasive fungal infections. With the aim of enhancing microbiology literacy and the understanding of microbial concepts, we set up a project for the collection of airborne spores (the principal agent through which human airways are exposed to fungi). Students from five high schools in the Oeiras municipality partnered with us as citizen scientists; they carried out sampling by collecting fungal spores on adhesive stickers. The fungal spores collected by the students were subsequently processed in the schools and our research laboratory. Results obtained by the students themselves revealed a large variety of fungal species capable of growing in a rich medium at 30°C. In the research laboratory, using selective isolation conditions, 40 thermotolerant fungi were isolated, 32 of which were taxonomically identified as aspergilla, mostly from within the Aspergillus fumigatus taxa, yet exhibiting high genetic heterogeneity. The protocols and results were presented to the students, who were made aware of the local dispersal of airborne fungal spores, including some from potentially pathogenic fungi. Through carrying out scientific activities, the students developed both the interest and the self-confidence needed to implement future environmental investigations.

Bryophytes of Two Peoples Bay Nature Reserve, Western Australia

Context Although the vascular flora of Western Australia is renowned for high species diversity and endemism, very little is known about the state’s moss and liverwort flora. Aims In 1984 we conducted surveys of bryophytes in Two Peoples Bay Nature Reserve. Methods We searched comprehensively for bryophytes at seven major habitats on the Reserve, collecting voucher specimens subsequently identified with modern literature and with the help of Australian bryophyte experts. We updated the text to reflect modern taxonomy and considering modern literature on phytogeography and hypotheses associated with OCBIL (Old, Climatically Buffered, Infertile Landscapes) theory. Key results A total of 38 species of mosses representing 25 genera from 13 families were identified along with 10 species of liverworts representing nine genera and six families. Two moss species (Distichium inclinatum and Tortella dakinii) were previously unknown from Western Australia. Another represented a new species (Pleurophascum occidentale) in a heretofore monotypic genus, family, and order. The Pottiaceae, with 11 species, was the most diverse family of mosses. The Lepidoziaceae, with three species, was the most diverse family of liverworts. Conclusions Lower levels of endemism in bryophytes versus vascular plants may reflect the bryophytes’ capacity for wide and long-distance dispersal of spores and fragments. Bryophyte diversity and endemism may be less than on extensive OCBILs because much of the Reserve emerged from the ocean as recently as the mid-Pleistocene. Implications This, the first listing published of bryophytes on a Reserve in WA, indicates the potential rewards for further survey of mosses and liverworts.

Sporulation and Dispersal of the Biological Control Agent Aspergillus flavus AF36 Under Field Conditions.

Aflatoxins are carcinogens produced by the fungi Aspergillus flavus and A. parasiticus that contaminate pistachio crops. International markets reject pistachio when aflatoxins exceed permitted maximum levels. Releasing the atoxigenic strain AF36 of A. flavus is the leading aflatoxin pre-harvest control method. The product AF36 Prevail, sorghum grains coated with AF36 propagules, has been used in California since 2017. However, a high percentage of grains of the Prevail fail to sporulate in orchards. Here, the effect of soil moisture on the percentage of AF36 product grains sporulating (SG) and the quantity of spores per grain using a sporulation index (SI) was determined. Under controlled conditions, SG was higher than 85% when soil moisture was 13% or more, and SI increased with increasing soil moisture from 8.4 to 21%. The highest AF36 sporulation occurred near the micro-sprinklers when the grains were not impacted by the irrigation water drops. Arthropod predation was responsible for lost product grains, which was more pronounced in non-tilled soil than in tilled soil. Dispersal of the AF36 spores decreased markedly with the height and distance from the inoculum source, following a pattern of diffusion equations. However, AF36 spores easily reached canopies of pistachios located 10 m from the inoculum source. Our results indicate that AF36 Prevail should be applied close to the irrigation line in the moist soil area but avoiding the areas where excess irrigation causes water accumulation. The biocontrol of aflatoxins in California's pistachio production areas was optimized by improving the field realization of the biological control agent.

Role of Rain in the Spore Dispersal of Fungal Pathogens Associated with Grapevine Trunk Diseases.

Grapevine trunk diseases are caused by a complex of fungi that belong to different taxa, which produce different spore types and have different spore dispersal mechanisms. It is commonly accepted that rainfall plays a key role in spore dispersal, but there is conflicting information in the literature on the relationship between rain and spore trapping in aerobiology studies. We conducted a systematic literature review, extracted quantitative data from published papers, and used the pooled data for Bayesian analysis of the effect of rain on spore trapping. We selected 17 papers covering 95 studies and 8,778 trapping periods, concerning a total of 26 fungal taxa causing Botryosphaeria dieback (BD), Esca complex (EC), and Eutypa dieback (ED). Results confirmed the role of rain in the spore dispersal of these fungi but revealed differences among the different fungi. Rain was a good predictor of spore trapping for ED (AUROC = 0.820) and BD (0.766) but not for the ascomycetes involved in EC (0.569) and not for the only basidiomycetes, Fomitiporella viticola, studied as for spore discharge (AUROC not significant). Prediction of spore trapping was more accurate for negative prognosis than for positive prognosis; a rain cutoff of ≥0.2 mm provided an overall accuracy of ≥0.61 for correct prognoses. Spores trapped in rainless periods accounted for only <10% of the total spores. Our analysis had some drawbacks, which were mainly caused by knowledge gaps and limited data availability; these drawbacks are discussed to facilitate further research.

In the social amoeba Dictyostelium discoideum, shortened stalks may limit obligate cheater success even when exploitable partners are available.

Cooperation is widespread across life, but its existence can be threatened by exploitation. The rise of obligate social cheaters that are incapable of contributing to a necessary cooperative function can lead to the loss of that function. In the social amoeba Dictyostelium discoideum, obligate social cheaters cannot form dead stalk cells and in chimeras instead form living spore cells. This gives them a competitive advantage within chimeras. However, obligate cheaters of this kind have thus far not been found in nature, probably because they are often enough in clonal populations that they need to retain the ability to produce stalks. In this study we discovered an additional cost to obligate cheaters. Even when there are wild-type cells to parasitize, the chimeric fruiting bodies that result have shorter stalks and these are disadvantaged in spore dispersal. The inability of obligate cheaters to form fruiting bodies when they are on their own combined with the lower functionality of fruiting bodies when they are not represent limits on obligate social cheating as a strategy.

Outcrossing mating system in natural populations of the endangered aquatic fern Ceratopteris thalictroides in China as revealed by microsatellite markers: implications for conservation

In this study, the mating system of the endangered aquatic fern Ceratopteris thalictroides in China was investigated using microsatellite markers. The estimates of the multilocus outcrossing rate (tm) and single-locus outcrossing rate (ts) were high at the species level (tm = 0.701 and ts = 0.595, respectively), indicating that C. thalictroides is a predominantly outcrossing species. Negative F (inbreeding coefficient of the maternal parents) values (-0.137) at the species level indicated an excess of heterozygotes and low inbreeding in the populations analyzed. Our investigation revealed that some of the natural and ex situ conservation populations of C. thalictroides have a prolific capacity for vegetative growth. The results showed that the homosporous pteridophyte C. thalictroides in China predominantly favors gametophytic crossing with a certain level of inbreeding along with vegetative growth. Ten populations have been established for ex situ conservation in Wuhan, China, with a survival rate of more than 90%, and mature spores were collected from them. Several factors, including high dispersal of spores and gametophytes by flowing water, high gene flow, and the wide distribution of the species in China, with the occurrence of some large populations, may have resulted in a high outcrossing rate in Chinese C. thalictroides. The high outcrossing rate of C. thalictroides showed that ex situ plantings are most suitable for enhancing possible mixing of the different populations, thus minimizing inbreeding.

Do Growers Using Solo Fungicides Affect the Durability of Disease Control of Growers Using Mixtures and Alternations? The Case of Spot-Form Net Blotch in Western Australia.

Growers often use alternations or mixtures of fungicides to slow down the development of resistance to fungicides. However, within a landscape, some growers will implement such resistance management methods, whereas others do not, and may even apply solo components of the resistance management program. We investigated whether growers using solo components of resistant management programs affect the durability of disease control in fields of those who implement fungicide resistance management. We developed a spatially implicit semidiscrete epidemiological model for the development of fungicide resistance. The model simulates the development of epidemics of spot-form net blotch disease, caused by the pathogen Pyrenophora teres f. maculata. The landscape comprises three types of fields, grouped according to their treatment program, with spore dispersal between fields early in the cropping season. In one field type, a fungicide resistance management method is implemented, whereas in the two others, it is not, with one of these field types using a component of the fungicide resistance management program. The output of the model suggests that the use of component fungicides does affect the durability of disease control for growers using resistance management programs. The magnitude of the effect depends on the characteristics of the pathosystem, the degree of inoculum mixing between fields, and the resistance management program being used. Additionally, although increasing the amount of the solo component in the landscape generally decreases the lifespan within which the resistance management program provides effective control, situations exist where the lifespan may be minimized at intermediate levels of the solo component fungicide. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

A new spatial model for tracking plant spore dispersal and disease spread

Plant diseases caused by spores can cause severe damage to crop production, resulting in yield losses of up to 75%. Spores can be carried over long distances by wind, water, insects, and humans, meaning that even one infected agricultural field can spread the disease to neighboring fields. Although mathematical models exist to describe the spread of plant diseases, they often do not take into account the transport and location of spores, which limits the ability to make spatial forecasts. To address this limitation, we developed a spatial model based on Healthy sites H, Latent sites L, Infected sites I, Removed sites R, and spore sites X (HLIRX), which describes the spore movement between fields, allowing us to simulate the spatial invasion of plant diseases. We analyzed the existence and stability of steady states in the model using the finite difference method. Our findings reveal that the disease-free equilibrium is unstable, while the boundary and endemic equilibria are asymptotically stable, depending on the spore dispersion term. Moreover, we observed that the dynamics of the population in each field exhibit a consistent pattern, with leftward or rightward shifts depending on the distance from the source of infection, which cannot be captured from the temporal model. We also investigated the impact of two spatial parameters, the dispersal kernel parameter and spore migration rate, and found that both parameters lead to an increase in the number of infected plants but have no significant effect on disease severity. In addition, we discovered that the time until the infected population peaks is linearly related to the distance between each field and the source of infection, with a Pearson correlation coefficient greater than 0.99 (p &amp;lt; 0.001). Our developed model provides a useful tool for studying the spatial dispersion of plant diseases distributed by spores, as it considers the transport and location of spores and can be used to make spatial forecasts.

Coherent spore dispersion via drop-leaf interaction.

The dispersion of plant pathogens, such as rust spores, is responsible for more than 20% of global crop yield loss annually. However, the release mechanism of pathogens from flexible plant surfaces into the canopy is not well understood. In this study, we investigated the interplay between leaf elasticity and rainfall, revealing how a flexible leaf structure can generate a lateral flow stream, with embedded coherent structures that enhance transport. We first modeled the linear coupling between drop momentum, leaf vibration, and the stream flux from leaf surfaces. With Lagrangian diagnostics, we further mapped out the nested coherent structures around the fluttering profile, providing a dynamical description for local spore delivery. We hope the mechanistic details extracted here can facilitate the construction of physically informed analytical models for local crop disease management.