Source Of Primary Inoculum Research Articles

In-Vivo and In-Vitro Investigation of Germination Rate of Buried Sclerotia, and Variability in Carpogenic Germination Among Sclerotinia sclerotiorum Isolates

The sclerotia of Sclerotinia sclerotiorum serve as a primary inoculum source for initiating infections. This study aimed to evaluate the effects of environmental factors on sclerotial germination under field conditions by establishing sclerotia depots to monitor apothecia appearance over four consecutive years. Additionally, the effects of soil moisture content (25%, 50%, 75%, and 95%), air temperature (10 °C/10 °C, 14 °C/10 °C, and 18 °C/10 °C), and light conditions (white and UV light) on sclerotial germination and apothecial formation were investigated under controlled conditions with a 17 h day/7 h night regime. Furthermore, variability in carpogenic germination among S. sclerotiorum isolates was examined. From 2021 to 2024, significant differences were observed in both the sclerotia germination rate and timing of germination within the season. High soil moisture, particularly prolonged wetness, and soil temperatures between 10 and 14 °C were key factors for apothecial formation under field conditions. Under controlled conditions, higher soil moisture levels (75% and 95%) accelerated sclerotial germination, with sclerotia incubated at 14 °C/10 °C germinating earlier after 38 days than those at 10 °C/10 °C or 18 °C/10 °C. Additionally, the type of light significantly affected apothecial formation, which was observed only in treatments exposed to a combination of white and UV light. Furthermore, significant variations were also found in the duration until sclerotia of different S. sclerotiorum isolates produced the first stipe and the first apothecium, indicating that the genetic characteristics of each isolate affect carpogenic germination.

Establishment of a Cas12a-Based Visual Detection Method Involving PMNT for the Colletotrichum gloeosporioides Species Complex.

Strawberry anthracnose, caused by Colletotrichum spp., is a devastating disease that significantly reduces strawberry yield and quality. This study aimed to develop a simple diagnostic method to detect infection by the Colletotrichum gloeosporioides complex (CGSC), the most predominant and virulent Colletotrichum species complex causing strawberry anthracnose in China. In this study, a Cas12aVIP diagnostic method was developed for the rapid detection of CGSC in strawberry seedlings. This method targets the β-tubulin gene and combines recombinase polymerase amplification (RPA), the CRISPR/Cas12a system, and a cationic-conjugated polythiophene derivative [poly(3-(3'-N,N,N-triethylamino-1'-propyloxy)-4-methyl-2,5-thiophene hydrochloride) (PMNT)] mixed with single-stranded DNA (ssDNA). This method shows high sensitivity (ten copies per reaction) and no cross-reactivity against related pathogens. The entire procedure, from sample to result, can be completed within 50 min, including simplified DNA extraction (15 min), RPA reaction (37°C for 20 min), CRISPR/Cas12a detection (37°C for 10 min), and visual detection by the naked eye (1-2 min). Furthermore, the Cas12aVIP assay successfully detected CGSC in naturally infected strawberry seedling samples in field conditions. Asymptomatic infected plants and plant residues have been identified as primary inoculum sources for CGSC. This method enables visible detection without the need for expensive equipment or specialized technical skills, thereby offering an efficient and straightforward approach for detecting CGSC in strawberries. The newly developed detection method can be used to promote healthier strawberry production.

Shifts in Fusarium Communities and Mycotoxins in Maize Residues, Soils, and Wheat Grains throughout the Wheat Cycle: Implications for Fusarium Head Blight Epidemiology.

Fusarium Head Blight (FHB), predominantly caused by Fusarium species, is a devastating cereal disease worldwide. While considerable research has focused on Fusarium communities in grains, less attention has been given to residues and soil, the primary inoculum sources. Knowledge of Fusarium spp. diversity, dynamics, and mycotoxin accumulation in these substrates is crucial for assessing their contribution to wheat head infection and the complex interactions among Fusarium communities throughout the wheat cycle. We monitored six minimum-tillage wheat fields, with maize as the preceding crop, over two years. Soils, maize residues, and wheat grains were sampled at four stages. Fusarium composition was analyzed using a culture-dependent method, species-specific qPCR, and EF1α region metabarcoding sequencing, enabling species-level resolution. The Fusarium communities were primarily influenced by substrate type, accounting for 35.8% of variance, followed by sampling location (8.1%) and sampling stage (3.2%). Among the 32 identified species, F. poae and F. graminearum dominated grains, with mean relative abundances of 47% and 29%, respectively. Conversely, residues were mainly contaminated by F. graminearum, with a low presence of F. poae, as confirmed by species-specific qPCR. Notably, during periods of high FHB pressure, such as in 2021, F. graminearum was the dominant species in grains. However, in the following year, F. poae outcompeted F. graminearum, resulting in reduced disease pressure, consistent with the lower pathogenicity of F. poae. Source Tracker analysis indicated that residues were a more significant source of Fusarium contamination on wheat in 2021 compared to 2022, suggesting that F. graminearum in 2021 primarily originated from residues, whereas F. poae's sources of infection need further investigation. Additionally, multiple mycotoxins were detected and quantified in maize residues during the wheat cycle, raising the question of their ecological role and impact on the soil microbiota.

Seed Tubers Are Not the Primary Inoculum Source in Water Yam (Dioscorea alata) Anthracnose Epidemics in the Caribbean

Seed Tubers Are Not the Primary Inoculum Source in Water Yam (Dioscorea alata) Anthracnose Epidemics in the Caribbean

Survival of Xanthomonas vasicola pv. vasculorum in Soil and in Corn Crop Residues under the Humid Subtropical Climate of Southern Brazil.

Bacterial leaf streak caused by Xanthomonas vasicola pv. vasculorum (Xvv) is an emerging disease in several corn-producing regions around the world. In Brazil, there is a lack of information on the survival of this bacterium in soil and crop residues. Thus, the objective of this study was to determine the survival of Xvv in soil and also in infected corn crop residues under the humid subtropical climate of southern Brazil. The survival of Xvv in soil was initially investigated in sandy and clayey soils maintained at 20, 25 and 30 °C under controlled conditions. The survival of the bacterium under field conditions was studied in artificially infested clayey soil. The survival of Xvv in corn crop residues was investigated in infected residues maintained on the soil surface or buried in the soil at 20 cm deep. Under controlled conditions, regardless of the type of soil, the bacterium survived longer at 20 °C than at higher temperatures. The bacterium survived for 40 days in clayey soil kept at 20 °C and four days in sandy soil maintained at 30 °C. Under field conditions, the survival of Xvv in the soil was only for 48 h and in infected corn crop residues for up to 15 days in the samples maintained on the soil surface. In samples of infected corn residues buried in the soil, the bacterium was only detected at the time the experiment was set up. In general, the results obtained in this study revealed that Xvv survives for a short period of time in soil and in infected corn crop residues under humid subtropical conditions. Therefore, soil and corn residues may not be highly important sources of primary inoculum for the development of bacterial leaf streak on corn crops under these conditions.

Development of a Long-Amplicon Propidium Monoazide-Quantitative PCR Assay for Detection of Viable Xanthomonas arboricola pv. pruni Cells in Peach Trees.

Bacterial spot is one of the most serious diseases of peach caused by the pathogen Xanthomonas arboricola pv. pruni (XAP), leading to early defoliation and unmarketable fruit. The pathogen can overwinter in peach twigs and form spring cankers, which are considered the primary inoculum source for early season leaf and fruitlet infection. The amount of overwintering bacterial inoculum plays a critical role for the bacterial spot development, but no reliable quantification method is available. Thus, we developed a long-amplicon propidium monoazide (PMA)-quantitative PCR (qPCR) assay for specific detection of viable XAP cells. The optimized PMA-qPCR assay used 20 μM of PMAxx for pure bacterial suspensions and 100 μM for peach twig tissues. The Qiagen Plant Pro Kit with an additional lysozyme digestion step was the DNA extraction protocol that yielded the best detection sensitivity with the bacteria-spiked peach twig extracts. The PMA-qPCR assay was tested with different mixtures of viable and heat-killed XAP cells in pure bacterial suspensions and bacteria-spiked peach twig tissues. The results showed that this assay enabled sensitive, specific, and accurate quantification of viable XAP cells as low as 103 CFU/ml with the presence of up to 107 CFU/ml of dead XAP cells, while suppressing the amplification of DNA from dead cells. For mixtures of viable and dead cells, the PMA-qPCR results were linearly correlated with the predicted concentrations of viable XAP (R2 > 0.98). Thus, the PMA-qPCR assay will be a suitable tool for quantifying overwintering XAP population on peach trees.

Development of K-Maryblyt for Fire Blight Control in Apple and Pear Trees in Korea.

K-Maryblyt has been developed for the effective control of secondary fire blight infections on blossoms and the elimination of primary inoculum sources from cankers and newly emerged shoots early in the season for both apple and pear trees. This model facilitates the precise determination of the blossom infection timing and identification of primary inoculum sources, akin to Maryblyt, predicting flower infections and the appearance of symptoms on various plant parts, including cankers, blossoms, and shoots. Nevertheless, K-Maryblyt has undergone significant improvements: Integration of Phenology Models for both apple and pear trees, Adoption of observed or predicted hourly temperatures for Epiphytic Infection Potential (EIP) calculation, incorporation of adjusted equations resulting in reduced mean error with 10.08 degree-hours (DH) for apple and 9.28 DH for pear, introduction of a relative humidity variable for pear EIP calculation, and adaptation of modified degree-day calculation methods for expected symptoms. Since the transition to a model-based control policy in 2022, the system has disseminated 158,440 messages related to blossom control and symptom prediction to farmers and professional managers in its inaugural year. Furthermore, the system has been refined to include control messages that account for the mechanism of action of pesticides distributed to farmers in specific counties, considering flower opening conditions and weather suitability for spraying. Operating as a pivotal module within the Fire Blight Forecasting Information System (FBcastS), K-Maryblyt plays a crucial role in providing essential fire blight information to farmers, professional managers, and policymakers.

Plant virus transmission during seed development and implications to plant defense system.

Most plants produce large amounts of seeds to disperse their progeny in the environment. Plant viruses have evolved to avoid plant resistance mechanisms and use seeds for their dispersal. The presence of plant pathogenic viruses in seeds and suppression of plant host defenses is a major worldwide concern for producers and seed companies because undetected viruses in the seed can represent a significant threat to yield in many economically important crops. The vertical transmission of plant viruses occurs directly through the embryo or indirectly by getting in pollen grains or ovules. Infection of plant viruses during the early development of the seed embryo can result in morphological or genetic changes that cause poor seed quality and, more importantly, low yields due to the partial or ubiquitous presence of the virus at the earliest stages of seedling development. Understanding transmission of plant viruses and the ability to avoid plant defense mechanisms during seed embryo development will help identify primary inoculum sources, reduce virus spread, decrease severity of negative effects on plant health and productivity, and facilitate the future of plant disease management during seed development in many crops. In this article, we provide an overview of the current knowledge and understanding of plant virus transmission during seed embryo development, including the context of host-virus interaction.

Temporal Dynamics and Dispersal Patterns of the Primary Inoculum of Coniella diplodiella, the Causal Agent of Grape White Rot.

Grape white rot can cause considerable yield losses in viticulture areas worldwide and is principally caused by Coniella diplodiella. The fungus overwinters in berry mummies on the soil surface or on the trellis and produces pycnidia and conidia that serve as primary inoculum. However, little is known about the temporal dynamics and dispersal pattern of C. diplodiella conidia. In this study, we investigated the production and dispersal of C. diplodiella conidia from a primary inoculum source, namely, affected mummified berries that overwintered in two vineyards in northern Italy in 2021 and 2022. Conidia of C. diplodiella were repeatedly produced in berry mummies from the budburst of vines to harvesting, with approximately 50 and 75% of the total conidia in a season being produced before fruit set and véraison, respectively. The production dynamics of C. diplodiella conidia over time were described by a Weibull equation in which the thermal time is the independent variable, with a concordance correlation coefficient of ≥0.964. A rainfall cutoff of ≥0.2 mm provided an overall accuracy of ≥0.86 in predicting conidial dispersal through rain splashes from berry mummies on the soil surface, with the number of dispersed conidia increasing with the amount of rainfall. The dispersal of conidia from mummies on the trellis by washing with rain required at least 6.1 mm of rain. The proposed mathematical equations and rain cutoffs can be used to predict periods with a high dispersal risk of C. diplodiella.

Host range study of powdery mildew disease of sunflower under glass house conditions

The Host range study of powdery mildew disease of sunflower experiment was undertaken in glass house conditions during Rabi 2017-18 and 2018-19 at MARS, Raichur. The powdery mildew conidia were inoculated on 10 different hosts viz, Green gram, Black gram, Pea, Horse gram, French bean, Cluster bean, Mothbean, Cowpea, Tomato and Chilli. Among 10 cultivated crops the pathogen found to infecting on 4 different hosts such as Greengram, Blackgram, Cluster bean and French bean. Hence these 4 hosts can be considered as collateral hosts. In absence of sunflower, pathogen can survive in these four hosts and can act as primary source of inoculum whenever the crop is grown.

A landscape-scale field survey demonstrates the role of wheat volunteers as a local and diversified source of leaf rust inoculum

Deploying disease-resistant cultivars is one of the most effective control strategies to manage crop diseases such as wheat leaf rust, caused by Puccinia triticina. After harvest, this biotrophic fungal pathogen can survive on wheat volunteers present at landscape scale and constitute a local source of primary inoculum for the next cropping season. In this study, we characterised the diversity of P. triticina populations surveyed on wheat volunteer seedlings for six consecutive years (2007–2012) at the landscape scale. A total of 642 leaf rust samples classified in 52 virulence profiles (pathotypes) were collected within a fixed 5-km radius. The pathotype composition (identity and abundance) of field-collected populations was analyzed according to the distance between the surveyed wheat plots and to the cultivars of origin of isolates. Our study emphasised the high diversity of P. triticina populations on wheat volunteers at the landscape scale. We observed an impact of cultivar of origin on pathogen population composition. Levels of population diversity differed between cultivars and their deployment in the study area. Our results suggest that wheat volunteers could provide a significant though highly variable contribution to the composition of primary inoculum and subsequent initiation of leaf rust epidemics.

Early detection of Phytophthora infestans in potato plants using hyperspectral imaging, local comparison and a convolutional neural network

An important primary inoculum source of Phytophthora infestans are latent infected seed potatoes. To remove those inoculum sources, it is necessary to detect these plants before symptom expression. Often, when a human can detect it by eye, sporulation has occurred and secondary spread might have commenced. Moreover, it is not feasible to check all potato plants by manual labour. It is possible to detect a P. infestans infection early, using hyperspectral imaging, however, models trained on the spectral information only, do not generalize, because the spectrum is very much dependent on the local conditions like soil humidity. A method is developed to detect P. infestans early by comparing spectra from infected plants with the spectra of healthy plants that have grown under similar conditions, i.e., in the same plant row, and creating an image that quantifies deviations. On those images in turn a convolutional neural network is trained, which is able to detect infections on plants grown in another field or a year later in a similar manner but under different conditions. The method has been tested in the field in a dry year with little potato late blight infection. In this experiment it has not been possible to detect the infection using hyperspectral imaging.

Management Strategies for Charcoal Rot of Sesame: A Review

Sesame (Sesamum indicum L.) commonly known as til is one of the important oilseed crop having good nutritional, biomedical and religious value. It is also called as “Queen of oilseeds” and among the oilseed crops , sesame ranks first for its higher oil content with a dietary energy of 6335kcal/kg in seeds. The crop is attacked by several pathogens causing serious diseases and act as major damaging factor to sesame crop cultivated in the whole world with severe losses of 7million tones yearly. The important diseases of sesame include charcoal rot (Macrophomina phaseolina, Fusarium wilt (Fusarium oxysporum), Phytophthora blight (Phytophthora parasitica) and phyllody (phytoplasma). Charcoal rot is caused by Macrophomina phaseolina has been a major threat to the successful cultivation of sesame in Haryana which causes about 5-100% loss. The pathogen being facultative in nature survives as microsclerotia in soil and infested plant debris that serve as the primary source of inoculum and have been found to persist within the soil up to three years.The pathogen not only persists in soil as saprophyte associated with other soil microorganisms but also transmitted through seed. Hence, it requires different management approaches to overcome this menace. So, keeping in view the present scenario ecofriendly management must be done by the use of botanicals and bio agents.

Detection of Brasiliomyces malachrae Causing Powdery Mildew on Ornamental Cotton (Gossypium hirsutum) plants in Mexico.

Cotton (Gossypium L.; Malvaceae) is the most important fiber crop worldwide, also as a source of vegetable protein and edible oil. Cultivated species of cotton were apparently domesticated independently in four separate regions, in both the Old and the New World. Due to its economic importance, it is necessary to study the diseases that limit its production. During July of 2020-2022, symptoms of powdery mildew were observed on 80 ornamental cotton plants in a nursery located in Cuautla (18°52'38"N; 98°58'28"W), Morelos, Mexico. Disease incidence was 29%. Signs first appeared as small white colonies, which subsequently developed into abundant mycelial grown mainly on the upper leaf surface. White patches of mycelia were observed on leaves. In advanced stages of the disease, plants exhibited symptoms of yellowing, necrosis, and early defoliation. Microscopic analysis from 10 plant samples showed that mycelia were amphigenous, epiphyllous, in thin patches and evanescent. Hyphae were hyaline, thin walled and hyphal appressoria were simply lobed. Chasmothecia (n=50) were sub-aggregate, generally spherical to subglobose (46-61 µm in diameter), whitish, subhyaline, smooth, with a peridium of a single cell layer and appendages were absent. Three asci per chasmothecia, subspherical, 30-44 × 26-38 µm, with 4-6 ascospores per ascus. Ascospores were hyaline, ellipsoid to ovoid (16-23 × 10-18 µm). The asexual phase was not observed. The characteristics observed correspond to Brasiliomyces malachrae (Braun and Cook 2012; Cabrera et al. 2018). A voucher specimen was deposited in the Herbarium of the Department of Plant-Insect Interactions at the Biotic Products Development Center of the National Polytechnic Institute under accession no. IPN 10.0114. To confirm identification, DNA was recovered from the fungus and the internal transcribed spacer (ITS) from one sample was amplified by PCR, using the primers ITS1/ITS4 (White et al. 1990). The sequence was deposited in GenBank (OQ546720) and showed 100% sequence homology (647/1642bp) with the type sequence of B. malachrae (LC191217) from Malvastrum coromandelianum in Argentina (Cabrera et al. 2018). Pathogenicity was verified through inoculation by gently dusting conidia from infected leaves onto leaves of five healthy cotton plants. Five noninoculated plants served as controls. All plants were maintained in a greenhouse at temperatures from 28±2°C and relative humidity ranging from 80±5%. The experiment was performed twice. Inoculated plants developed powdery mildew symptoms after 14 days, whereas the control plants remained healthy. The fungus on the inoculated leaves was morphologically identical to that originally observed on diseased plants, thus fulfilling Koch's postulates. To our knowledge, this is the first report of Brasiliomyces malachrae causing powdery mildew on Gossypium hirsutum in Mexico and North America (Farr and Rossman 2023). Powdery mildew on G. hirsutum caused by B. malachrae has been previously identified in Venezuela by Hanlin and Tortolero (1984). This disease could be a primary source of inoculum of powdery mildew for commercial cotton plantations, derived from the free movement of ornamental plants.

Pistachio Male Inflorescences as an Alternative Substrate for the Application of Atoxigenic Strains of Aspergillus flavus.

Aflatoxins are carcinogens mainly produced by Aspergillus flavus and A. parasiticus in susceptible crops, including pistachio. The primary inoculum sources of these pathogens are plant debris in the orchard soils. In Californian fields, one approach to controlling aflatoxin contamination is based on releasing the atoxigenic strain of A. flavus AF36 in inoculated (coated) sorghum grains (AF36 Prevail). However, this control method can fail due to poor sporulation of the AF36 strain or sorghum grain losses due to predation. In 2008 and 2018, we showed that toxigenic and atoxigenic isolates of Aspergillus spp. frequently colonized fallen inflorescences of male pistachio trees. Under controlled conditions, strain AF36 profusely colonized pistachio male inflorescences when humidity was higher than 90%. However, there were significant differences between types of inflorescence (aerial > fallen). In 2016, we considerably (P = 0.015) increased the population of AF36 on the canopies of trees when fallen inflorescences were inoculated with AF36, compared with untreated trees. In 2017 and 2018, these differences were not detected (P > 0.05) due to cross-contamination of strain AF36 between seasons and neighboring plots. In any case, the density of AF36 spores on the canopy of the inflorescence-treated trees was similar (P > 0.05) to that on trees treated with the commercial product. Here, we present a new method for applying strain AF36 based on using a natural, abundant, and uniformly distributed substrate in pistachio fields, and we discuss how it can be improved. Furthermore, our results indicate that, in pistachio orchards where biocontrol practices are not conducted, eliminating this important source of toxigenic Aspergillus inoculum is recommended.

Primary inoculum of Venturia inaequalis (Cooke) Wint. in its asexual form in apple – a review

This review summarizes and discusses the geographical distribution, overwintering, dissemination, and management of the asexual stage of Venturia inaequalis, the fungal pathogen causing apple scab. The asexual overwintering of V. inaequalis has primarily been described as wood scab, superficial scab, or bud scab, and more rarely, it is mentioned as overwintering on infected leaves and fruits still attached to the trees. Wood scab is fungal pustules found on new and 1-year-old shoots, but it is also found on 2-year-old wood. It has been reported in many apple-growing countries throughout the world; however, most reports of wood scab being an important source of primary inoculum, as well as the most in-depth studies, are from the UK. Reports from some countries describe what is named superficial scab, which are symptomless infections of the pathogen on shoot surfaces. Overwintering of V. inaequalis on the inner or outer bud scales has also been reported in some countries. Infections may appear as small lesions on the bud scales, but numerous conidia have also been found in buds without symptomatic fungal tissue. The incidence and quantity of overwintering in the asexual stage are dependent on the amount of scab in the previous season, growth characteristics, and cultivar susceptibility. In orchards with limited options for fungicide control and/or in orchards with loss of scab control in the preceding season, conidia of V. inaequalis should not be underestimated as a source of primary inoculum.

Inhibition of tomato spotted wilt virus nucleocapsid protein using phytochemical lupenone as spraying agent: A cutting-edge computational approach

About & backgroundTomato spotted wilt virus (TSWV) is one of the most harmful diseases affecting the growing and making of tomatoes (Solanum lycopersicum) worldwide. With so many pests and disease-causing organisms making it hard to grow crops, viruses can be easy to forget about as a threat. But viruses can cause damage that can't be fixed and significant crop losses if they aren't found and stopped quickly. The epidemiology of the diseases caused by TSWV remains poorly understood. It was not until 1993 that scientists could prove that TSWV replicated inside its vector. The vast host range of the TSWV and the existence of at least ten different species of thrips capable of spreading the virus make eliminating the primary inoculum sources problematic. Also, virulent thrips may endure the winter in the field. In Georgia, it is thought that tomato crops lose about $9 million yearly, and growers on the west coast have said that the virus damages up to 50% of their tomato plants. ResultsFinally, we performed virtual screening and found 10 phyto-compounds from Euphorbia segetalis and then accelerated to molecular re-docking. We surprisingly found that Lupenone is the most potent compound against nucleocapsid of tomato spotted wilt virus. We found a good docking score of Lupenone −8.99 kcal/mol with viral nucleocapsid protein. Hence, spraying Lupenone on tomato plants can actively prevent tomato spotted wilt virus and boost tomato yield by enhancing its drought resistance. Finally, Lupenone, a phyto-compound from Euphorbia segetalis, inhibits the active site of tomato spotted wilt virus nucleocapsid and prevents tomato plants from wilting.

Prvi nalaz teleomorfnog stadijuma prouzrokovača sive pegavosti lista i klasa pšenice Leptosphaeria nodorum u Srbiji

Parastagonospora nodorum (teleomorph Leptosphaeria nodorum) is the causal agent of septoria nodorum blotch (SNB). It was first discovered on wheat in 1845. and is common in regions with relatively high or periodically high rainfall. P. nodorum causes symptoms on all above-ground parts of the plant, including leaves, stems, glumes, and awns. The pathogen overwinters on wheat crop residues in the form of pseudothecia and pycnidia. Ascospores released from pseudothecia typically serve as the primary source of inoculum, but conidia released from pycnidia on crop residues can also infect seedlings. Additionally, the fungus is known to survive on seeds in the form of dormant mycelium, making infected seeds a potential source of primary infection. During the 2022/2023 growing season, precipitation totals in April (63.9 mm) and May (124.8 mm) exceeded seventeen-year averages, creating conditions conducive to occurence of SNB. Microscopic examination of lesions on leaves of wheat variety revealed the presence of the sexual stage (L. nodorum) for the first time in Serbia. The asexual stage (P. nodorum) was observed on infected ears of different varieties. This study highlights the need for more attention in monitoring conditions that could lead to outbreak SNB in wheat production areas in Serbia.

The impact of climate change in the spread of Pythium myriotylum in ginger: a critical review

Climate change is a growing concern due to its potential impact on biotic stressors, particularly fungal infections, such as Pythium myriotylum, which causes significant damage to ginger plants. Among the several yield-reducing fungal diseases targeting ginger, Pythium myriotylum is known to cause significant damage through rhizome rot and damping off. Scientific studies have explored the survival and spread of P. myriotylum in gingers and other crops that are thought to be caused by climate change. Oospores, the primary inoculum source, are crucial for the P. myriotylum's life cycle and disease progression. To mitigate the effects of P. myriotylum in ginger, adaptation techniques such as crop rotation, pesticide use, and breeding of resistant varieties can be developed. However, understanding the current spread of P. myriotylum and its limitations is crucial for future research. This review discusses the current status of P. myriotylum's importance in ginger, the effects of climatic variables on its life cycle, survival, and spread, adaptation strategies, and the effects of climate change on it. It also identifies significant knowledge gaps for future research.

Colletotrichum abscissum: Detection on symptomless citrus leaves and symptomatic citrus flowers using high‐resolution melting analysis

AbstractHigh‐resolution melting (HRM) analysis has been recently applied for the diagnosis of plant diseases. This cost‐effective method is advantageous over standard PCR as it does not require DNA band visualization or the use of probes necessary for quantitative PCR. Colletotrichum abscissum causes postbloom fruit drop of citrus (PFD) and survives asymptomatically on vegetative tissue. Quiescent appressoria on citrus leaves are the primary source of inoculum between flowering periods. Early PFD symptoms may be misidentified as physical damage on citrus flowers. Our objectives were to validate an HRM‐based method to rapidly identify C. abscissum on citrus leaves and flowers. We screened seven previously published primer pairs and concluded that the most effective set of primers was CaITS‐F and CaITS‐R815. We evaluated three different DNA extraction methods, two with a purification step (DNeasy Plant Mini and PowerSoil kits) and a faster method without a purification step (buffer GEB2). We inoculated citrus leaves with C. abscissum conidial suspensions of varying concentrations and HRM analysis detected as few as 200 C. abscissum spores using DNeasy Plant Mini or DNeasy PowerSoil kits for DNA extraction. As expected, samples extracted with GEB2 buffer reduced HRM sensitivity. We further collected field samples from areas with high and low C. abscissum inoculum levels. The HRM method could detect the pathogen in high inoculum areas from both leaves and flowers regardless of the extraction method used. In summary, we describe a new molecular diagnostic tool to detect C. abscissum on citrus during its asymptomatic and symptomatic stages.