Rust Incidence Research Articles

Transmission pathways for the stem rust pathogen into Central and East Asia and the role of the alternate host, barberry

Abstract After many decades of effective control of stem rust caused by the Puccinia graminis f.sp. tritici, (hereafter Pgt) the reported emergence of race TTKSK/Ug99 of Pgt in Uganda reignited concerns about epidemics worldwide because ∼90% of world wheat cultivars had no resistance to the new race. Since it was initially detected in Uganda in 1998, Ug99 variants have now been identified in thirteen countries in Africa and the Middle East. Stem rust has been a major problem in the past, and concern is increasing about the risk of return to Central and East Asia. Whilst control programs in North America and Europe relied on the use of resistant cultivars in combination with eradication of barberry (Berberis spp.), the alternate host required for the stem rust pathogen to complete its full lifecycle, the focus in East Asia was principally on the use of resistant wheat cultivars. Here, we investigate potential airborne transmission pathways for stem rust outbreaks in the Middle East to reach East Asia using an integrated modelling framework combining estimates of fungal spore deposition from an atmospheric dispersion model, environmental suitability for spore germination, and crop calendar information. We consider the role of mountain ranges in restricting transmission pathways, and we incorporate a representation of a generic barberry species into the lifecycle. We find viable transmission pathways to East Asia from the Middle East to the north via Central Asia and to the south via South Asia and that an initial infection in the Middle East could persist in East Asia for up to three years due to the presence of the alternate host. Our results indicate the need for further assessment of barberry species distributions in East Asia and appropriate methods for targeted surveillance and mitigation strategies should stem rust incidence increase in the Middle East region.

Destructive fungal disease survey of common bean (Phaseolus vulgaris L.) rust (Uromyces appendiculatus) in Southern Ethiopia

Common bean (Phaseolus vulgaris L.) is important legume crop world-wide and in Ethiopia for its multipurpose uses. Common bean rust, is the most destructive fungal disease that severely reduces bean yield. For years, rust appeared in a farmer's field in Southern Ethiopia; however, the disease's significance remains unclear. The research aimed to ascertain the distribution and intensity of common bean rust, as well as elucidate the association of biophysical parameters. The field survey was conducted in southern Ethiopia in 2022. Ninety percent of the 78 commonbean fields were affected by common bean rust. Mareko, Meskan, Duguna Fango, Damot Woide, and Demba Gofa had 100% of the fields affected, and Boricha had 90%. Damot Woide and Lanfuro had the highest and lowest mean rust incidence rates, respectively, 59.2% and 22.5%. Duguna Fango had the highest rust severity (35.5%), while Lanfuro had the lowest (13.5%). In the research areas, the biophysical factors, either alone or in combination, have a significant impact on the intensity of common bean rust. The current investigation verified the distributionand the association biophysical factors with common bean rust. In addition, the survey of the disease and the identification of factors should continue over time and space.

Virulence of Puccinia coronata var avenae f. sp. avenae (oat crown rust) in Canada during 2016 to 2020 and comparison of extensive vs intensive sampling methods

Puccinia coronata var avenae f. sp. avenae (Pca), the causal fungus of crown rust of oats, is a significant threat to oat production in the eastern prairie region (Manitoba and eastern Saskatchewan; EPR), Ontario and Quebec (eastern Canada; EC), in Canada. Development of oat lines with effective resistance to Pca has been a priority for oat breeding programmes in Canada, and helped mitigate reductions in oat yield and quality. This requires knowledge of the virulence characteristics of the Pca population in Canada. Our objectives were to determine the incidence and severity of Pca in Canada, the presence and frequency of virulence and races in Pca populations and compare the traditional extensive sampling method (few isolates per field from many fields) to an intensive sampling method (many isolates per field from a few fields) for obtaining genetically diverse collections. The incidence and severity of crown rust of oat in Canada was lower in 2016 to 2020 than has been reported in previous years. Virulence to all the 24 Pc genes studied was observed over the 5 years in EC and the EPR. The most effective genes were Pc94, Pc98 and Pc101 in EC and Pc50, Pc96, Pc97 and Pc98 in the EPR. Approximately 81% of 424 races identified were of unique virulence phenotypes over the 5 years, indicating a highly variable Pca population in Canada. Races JTQG-91 and GTQG-91 were the most common races identified. Collections of Pca obtained using the extensive sampling method were observed to be more genetically diverse than collections obtained using the intensive sampling method in 2018 and 2020, but not in 2019.

A potential cause for extensive dieback of Acacia mearnsii plantation in highland districts of Awi zone, northwestern Ethiopia

Although Acacia mearnsii De Wild has rapidly expanded for economic and ecological purposes in the highland districts of the Awi zone, northwestern Ethiopia, recent plantations have suffered from severe defoliation, dieback, and stunted growth. We conducted this study in four districts that hold potential for A. mearnsii plantations. The study examined the identification of the causal agent, its occurrence, and local community perceptions of the plantation's significant dieback. Most respondents (75.8 %) indicated that the substantial dieback began in the rainy season of 2020 and spread rapidly. They also noted that close spacing of plantings and limited silvicultural measures exacerbated the damage. We discovered in this study that the wattle rust disease caused by the Uromycladium acacia fungus was the root cause of significant dieback for A. mearnsii plantations. The incidence and severity of this wattle rust varied significantly (p = 0.001) between districts, seasons, and plantation age groups. In Fegita-Lekuma district, the maximum disease severity was over 72 % in plantations up to two years after planting during the rainy season. The progression of the wattle rust disease caused by U. acacia has led to the loss of A. mearnsii plantations in the Awi zone, resulting in a severe economic and environmental crisis. Consequently, we should apply fungicides to seedlings at nursery sites in the short term. Eventually, however, the focus should shift towards prioritizing disease-resistant species and implementing proper forest management practices. This should be achieved through scientific initiatives that engage key stakeholders in areas where this tree species could potentially grow.

Influence of Climatic Factors on Rust Severity in Sorghum in Dharwad, Karnataka, India

Sorghum rust, caused by Puccinia purpurea, significantly reduces crop yield, affecting plant growth and grain quality. Understanding the impact of weather parameters on disease incidence is crucial for timely disease management, to enhance crop resilience and yield stability. This study aims to identify and quantify the relationship between weather parameters and the incidence of sorghum rust, to inform decision-making on disease management strategies. A comprehensive analysis was conducted utilizing 17 years of secondary data (2006-2022) sourced from the All India Coordinated Research Project (AICRP) on Sorghum and the Department of Agrometeorology at the Climate Model Intercomparison Project (CMIP), University of Agricultural Sciences (UAS), Dharwad. The study employed statistical methods, including Multiple Linear Regression (MLR) and Step-wise Regression, to model the dependence of rust disease incidence on independent variables such as precipitation, temperature, relative humidity, wind speed, radiation, and heat flux. The results revealed the MLR model explains 65.45% of the variation and the Step-wise Regression model identifies four critical parameters- relative humidity, heat flux, wind speed, and radiation that together accounted for 65.09% of the variation without exhibiting multicollinearity (Variance Inflation Factor values below 10). These findings enhance the understanding of environmental impacts on sorghum rust and can inform future agricultural management strategies for disease prediction and control.

Корончатая ржавчина овса: роль сорта, погоды и уровня минерального питания в условиях Западной Сибири

Abstract. The purpose of this study is to assess the factors influencing the incidence of crown rust in oats. Materials and methods. The work was carried out in 2020–2021 at an experimental field located in the northern forest-steppe of the Trans-Urals. The object of the study were three cultivars of Tyumen breeding: Talisman, Otrada and Foma, which were sown on different agricultural grounds, ensuring the formation of yields from 3.0 to 6.0 t/ha of grain. The length of oat vegetation was determined at different levels of mineral nutrition; the degree of disease development and its prevalence in crops. Weather conditions in the years of research differed from the average long–term data: 2020 was hot and moderately dry; 2021 was abnormally hot and arid; 2022 was moderately hot and humid. Results. It has been experimentally proved that the application of fertilizers in doses N150P60 and N200P80 increases the vegetation of oats by 18–21 days due to the prolongation of the second half of the growing season. This leads to an increase in the incidence and prevalence of crown rust. The Foma variety turned out to be the most stable, in which the considered indicators were almost two times lower relative to the Talisman and Otrada cultivars. It was found that the degree of disease development depends on the variety by 27 %; by 21 % on the dose of mineral fertilizers and by 35 % on the weather conditions of the growing season. The prevalence of crown rust in oat crops mainly depends on the variety and mineral fertilizers – the degree of influence of these factors is 43 and 35 %, respectively. Scientific novelty. For the first time, the role of each factor on the susceptibility of modern varieties of oats to crown rust was studied and determined. A correlation has been established between the level of mineral nutrition and the degree of development of the disease. Recommendations. To reduce the risk of crown rust damage to oat crops in the conditions of the Northern Urals, it is recommended to use the Foma variety with the introduction of mineral fertilizers for a planned yield of no more than 5.0 t/ha of grain (N150P60).

Identification of SNP Markers and Candidate Genes Associated with Major Agronomic Traits in Coffea arabica.

Genome-wide association studies (GWASs) allow for inferences about the relationships between genomic variants and phenotypic traits in natural or breeding populations. However, few have used this methodology in Coffea arabica. We aimed to identify chromosomal regions with significant associations between SNP markers and agronomic traits in C. arabica. We used a coffee panel consisting of 195 plants derived from 13 families in F2 generations and backcrosses of crosses between leaf rust-susceptible and -resistant genotypes. The plants were phenotyped for 18 agronomic markers and genotyped for 21,211 SNP markers. A GWAS enabled the identification of 110 SNPs with significant associations (p < 0.05) for several agronomic traits in C. arabica: plant height, plagiotropic branch length, number of vegetative nodes, canopy diameter, fruit size, cercosporiosis incidence, and rust incidence. The effects of each SNP marker associated with the traits were analyzed, such that they can be used for molecular marker-assisted selection. For the first time, a GWAS was used for these important agronomic traits in C. arabica, enabling applications in accelerated coffee breeding through marker-assisted selection and ensuring greater efficiency and time reduction. Furthermore, our findings provide preliminary knowledge to further confirm the genomic loci and potential candidate genes contributing to various structural and disease-related traits of C. arabica.

Fruiting of Cronartium and Coleosporium rust fungi on Melampyrum spp. in Scots pine stands under various forest management applications in northern Finland

Cronartium pini is the causal agent of Scots pine blister rust in northern Europe. New silvicultural methods have recently been launched to manage Pinus sylvestris stands in Finland. Continuous-cover-forest management (CCF) is an approved alternative method for the traditional rotation-forest management (RF). The aim of this study was to compare fruiting and disease incidence of C. pini in forest stands managed applying the CCF and RF approaches. The incidence of C. pini-caused disease was assessed on P. sylvestris before, and on alternate herbaceous plant hosts Melampyrum pratense and M. sylvaticum one year after the CCF or RF application procedures and compared between several forest management types such as seed-tree cutting (STC), clearcutting (CC), gap cutting (GC), selection cutting (SC) and uncut control in seven study sites. Fruiting of the needle rust fungus, Coleosporium tussilaginis f. sp. melampyri, was also investigated. In 2020–2021, the number of P. sylvestris trees with symptoms of C. pini was low in all management types, and disease incidence varied from 0% to 2.8% among the management types. There was no statistically significant difference in the frequency of symptomatic pines between the management types and study sites at the beginning of the silvicultural management operations. Ten M. sylvaticum and/or M. pratense from five sample plots were collected in each managed stand. The incidence of symptomatic leaves of C. pini on M. sylvaticum varied from 0.6% to 7.7% among the management types and on M. pratense from 0% to 1.2% one year after the management applications. Coleosporium needle rust was more common than C. pini on Melampyrum spp. The percentage of leaves with C. tussilaginis f. sp. melampyri telia varied from 7.9% to 55.4% on M. pratense and from 0.6% to 24.8% on M. sylvaticum among the management types. The frequency of C. pini telia on M. pratense did not differ between the management types. The frequency of C. tussilaginis f. sp. melampyri telia on M. pratense did not differ between study sites, but it was significantly higher in unmanaged control stands compared to CC- or STC-managed stands a year after the management application. This indicated that the rust fungus fruited on Melampyrum more abundantly in forest stands that had the highest tree density prior to its fruiting. The results provide basic information of rust incidence in forest stands shortly after their management. The long-term effect of the different forest management types on rust incidence both on pines and alternate hosts will be assessed periodically years later. Keywords: alternate hosts; Melampyrum pretense; Melampyrum sylvaticum; Pinus sylvestris; rust diseases; Scots pine blister rust

Disease Incidence of Leaf Rust of Soybean Caused by Phakopsora pachyrizi Planted in Mahogany Agroforestry System

Abstract Soybean (Glycine max L.) is one of the agricultural commodities needed in high quantities in Indonesia. Using agroforestry systems for soybean cultivation can solve the domestic fulfillment of soybean needs. The moist environmental conditions of agroforestry plantings due to shading make soybeans susceptible to leaf rust disease. The pathogen Phakopsora pachyrhizi causes leaves to fall off early, inhibiting soybean seed pod growth. Research on the incidence of leaf rust disease in several soybean varieties is essential to optimize soybean production in agroforestry systems. The study was conducted from June to October 2023 in the Special Purpose Forest Area (KHDTK) of Alas Bromo, Karanganyar, Central Java, Indonesia. The experiment used a randomized experimental design (RAK) with seven soybean varieties: Anjasmoro, Agromulyo, Dena-1, Dena-2, Denasa-1, Denasa-2, and Devon-1. Disease incidence observation was based on visual symptoms. The disease incidence was in the range of 3.33-26.67%. The highest incidence occurred in the Denasa-1 and Dena-2 varieties, while the lowest was in the Anjasmoro and Dena-1 variety.

Leaf Rust Infection Phakopsora pachyrhizi on Seven Soybean Varieties in Pine Agroforestry System

Abstract The agroforestry farming system is an alternative to increasing soybean production in Indonesia. However, in its cultivation, there are obstacles in the form of attacks by leaf rust pathogens. Leaf rust caused by the P. pachyrhizi fungus can reduce soybean production, depending on the variety and environmental conditions. This research was conducted from June to September 2023 on the KHDTK (Kawasan Hutan dengan Tujuan Khusus) Forestry Alas Bromo, Karanganyar, Central Java, Indonesia, to explore the leaf rust incidence in soybean varieties. This research used a completely randomized block design (CRBD) consisting of seven soybean variety treatments: Anjasmoro, Argomulyo, Dena-1, Dena-2, Denasa-1, Denasa-2, and Devon-1, and repeated three times. The variable observed was disease incidence. The results showed that all soybean varieties tested could be infected with the leaf rust pathogen. The lowest leaf rust infection was found in the Devon-1 variety (6.0%), and the highest infection occurred in the Dena-1 variety (20.0%). This is thought to be related to genetic traits and environmental conditions strongly influencing the growth and development of the P. pachyrhizi pathogen.

Can climate variability and landscape position predict white pine blister rust incidence, mortality due to the disease, and regeneration in whitebark pine?

Invasive forest pathogens, like Cronartium ribicola (Fisch), the fungus that causes white pine blister rust, threaten native tree species. Federally listed whitebark pine ( Pinus albicaulis Engelmann) is highly susceptible and faces extensive mortality due to this disease. Understanding infection conditions and disease incidence variability is crucial for management and restoration efforts. We surveyed whitebark pine stands in Glacier National Park, Montana, USA from 2020 to 2022, examining the impact of landform and climate on tree mortality, rust incidence, cone production, and regeneration. Our analysis revealed that tree diameter, elevation, and aspect significantly influenced mortality, rust incidence, and cone production, while climatic factors such as spring solar radiation, humidity, and late summer snowpack also played key roles. Regeneration was primarily affected by elevation, geographic location, and humidity. Although landform variables similarly predicted disease incidence in this and other studies, climatic drivers varied by region, emphasizing the need to consider region-specific landform and climate for effective management. Our study highlights the importance of protecting large trees, which harbor genetic diversity crucial for recovery and adaptation to disturbance and climate change.

Virulence phenotypes of Puccinia graminis on barley, wheat and oat in Canada from 2020 to 2022

Stem rust of barley and wheat is caused by the obligate pathogen Puccinia graminis f. sp. tritici (Pgt) and stem rust of oat is caused by P. graminis f. sp. avenae (Pga). Stem rust can be a very destructive disease of cereal crops and, until the development of resistant host varieties, was responsible for millions of dollars of losses to producers. Genetic host resistance is the most common and effective method to control stem rust on cereals. Knowledge of the virulence genes and races present in the pathogen population is important to identify effective host resistance genes for use by cereal plant breeders. The objectives of this study were to determine the incidence and severity of P. graminis in wheat, barley and oat in Manitoba, Canada, and assess the virulence frequencies and races of isolates collected from Manitoba, Saskatchewan and Ontario, Canada during 2020 to 2022. Stem rust incidence and severity was very light in Manitoba in 2020, 2021 and 2022. Virulence was not observed on resistance genes Sr30, Sr24 and Sr31 from Canadian collections of Pgt isolates made during 2020 to 2022. Race QFCSC was the most common race of Pgt in Canada, and races MCCFC and TPMKC were also common in Manitoba in 2022. Virulence to resistance genes Pg6, Pg10 and Pg16 was not observed among Pga isolates. The most common race of Pga from Manitoba and Saskatchewan was TGN, followed by SGB and TJS. The most frequent Pga races were TDJ, TDD and TGN in Ontario.

Behavior of 33 coffee (Coffea sp.) accessions of the Catimor type in San Ramón, Chanchamayo, Perú

Coffee has been cultivated in Peru for over 100 years, and since then, various commercial varieties have been introduced, mostly informally, although this approach has been changing in recent years, benefiting national coffee farming. Within this context, documenting the presence of Catimors is necessary, as it is an important group of varieties with presence in all coffee-producing areas. This study aimed to understand the characteristics of 33 Catimor-type coffee accessions in San Ramón, Chanchamayo, Peru. The study was conducted during the 2018-2019 coffee growing season. The location was at the Coffee Germplasm Bank of the National Agrarian University La Molina (BGC-UNALM), located on the "La Génova" estate, in San Ramón, Chanchamayo, Peru, at an altitude of 965 meters above sea level, 11°05.70' LS and 75°20.969' LO. Thirty-three accessions were analyzed with 5 replications each, evaluating the incidence of rust (%), infestation level of coffee berry borer (%), number of harvests, weight of one hundred ripe fruits (g), weight of pulp of one hundred ripe fruits (g), weight of one hundred seeds (g), cherry coffee yield (quintal [qq] ha-1), dry parchment coffee yield (qq ha-1), and the ratio of dry parchment coffee to cherry coffee. Considering that the finalweight in kg of each field harvest was obtained and then transformed into quintals (1 qq equals 46 kg). The results showed that Catimors are a group of varieties whose main characteristic is resistance to coffee rust. In this trial, 11 out of the 33 evaluated accessions had zero incidence, meaning they showed no symptoms of the disease during the study period. They also showed a high yield of dry parchment coffee; in this case, the most outstanding accessions were UNACAF-70 and UNACAF-114, with 54.582 qq ha-1and 42.88 qq ha-1; respectively. It was concluded that Catimors can be used in integrated management programs for coffee rust in Peru due to their resistance to coffee rust and high yield.

Evaluation of Biocontrol-based Formulations against Late Leaf Spot and Rust in Groundnut

This study investigated the efficacy of various biocontrol-based formulations against late leaf spot (LLS) (Phaeoisariopsis personata) and rust (Puccinia arachidis) in groundnut. Pot culture and field experiments were conducted during the Kharif season (June-September) of 2022. Disease incidence of both late leaf spot and rust was significantly lower in groundnut plants treated with a combination of biocontrol-based formulations compared to control. The most effective eco-friendly treatment included a combination of Trichoderma asperellum, Pseudomonas fluorescens, fortified lignite fly ash and Annamalai mixture. This combination significantly reduced lesion frequency and Percent Disease Index (PDI) for both diseases at 50, 70 and 90 DAS, compared to other treatments. The combination of biocontrol-based formulations also significantly increased the pod yield. Furthermore, the same treatment increased the induction of defense enzymes peroxidase (2.22 fold), polyphenol oxidase (1.28 fold) and phenylalanine ammonia-lyase (6.25 fold). While Carbendazim effectively reduced disease incidence, it was surpassed by the biocontrol-based module in terms of both disease control and yield. These findings suggest that biocontrol-based formulations can be a sustainable approach for managing LLS and rust diseases in groundnut cultivation.

Elucidating the Etiology and Temporal Progress of Rust on Physic Nut Genotypes and Their Relationship with Environmental Conditions in Ecuador

Physic nut (Jatropha curcas L.) has emerged as a promising fruit crop in Ecuador, but the recent identification of rust poses a potential threat to its productive development. This study focused on elucidating the morphological aspects of the basidiomycete and assessing rust intensity across different canopy levels of physic nut hybrids and genotypes under field and semi-controlled conditions in Manabí, Ecuador. For the first time, this study confirms that Phakopsora arthuriana should be responsible for rust on physic nut in Ecuador based on the characteristics of the fungal structures. Rust incidence was 100% across all canopy layers, with the lower and middle canopies exhibiting higher severity and lesion numbers than the upper canopy. Using the Weibull nonlinear distribution model, we epidemiologically modeled disease progression, revealing that hybrid JAT 001100 displayed the highest temporal progress, recording 15% severity and an area under the disease progression curve of 3228.9 units. Promising genotypes CP-041 and CP-052 demonstrated lower rust intensity. Environmental parameters, including dew point, temperature, precipitation, and relative humidity, were correlated with rust severity and lesion numbers. In greenhouse assays, hybrid JAT 001165 showed higher severity, whereas JAT 001103 and JAT 001164 had more lesions than other genotypes. In contrast, promising genotypes CP-041 and CP-052 consistently exhibited lower rust intensity in both field and greenhouse environments. This study demonstrated that P. arthuriana could be epidemiologically modeled with the Weibull model, providing crucial insights into the dynamic interplay between rust infection and physic nut hybrids and genotypes under diverse conditions in the Manabí region of Ecuador.

Effectiveness of Rhodococcus erythropolis strain OPI-01 on the fungal development in winter wheat

Abstract. Behzad A, Diakite S, Astarkhanova TS, Pakina EN, Allen D, Mohammadi PM, Diarra O, Saquee FS. 2024. Effectiveness of Rhodococcus erythropolis strain OPI-01 on the fungal development in winter wheat. Biodiversitas 25: 1063-1070. One of the means of sustainable wheat production is using bacterial pesticides, which can synthesize phytohormonal substances with antibacterial and antifungal action. Therefore, the work aimed to study the effect of different doses of a new growth regulator Restart, ZH (Rhodococcus erythropolis D strain OPI-01) on winter wheat yield. The findings of field experiments on the effect of plant growth regulator R. erythropolis strain OPI-01 method of pre-sowing treatment of seeds (at 0.1 L/t and 0.2 L/t), and soil spraying just before sowing (-0.5 l/ha) revealed that on average, during the 2020-2021 and 2021-2022 seasons, the number of productive stems increased by a margin of 23-30, the number of grains in 1 ear increased in the experimental units by 16.2-19.4%, and the length of the ear by 0.3-0.7cm, gluten varied from 32.3 to 33.8%, yield increased from 27.8-33.0% relative to the control. Disease severity and incidence of powdery mildew, brown rust and Septoria disease in plots amended withR. erythropolis strain OPI-01 was 2-fold less than in the control plots. Research trials show the efficacy of R. erythropolis strain OPI-01 under field conditions as a plant growth regulator and a potential microbial fungicide against some foliar diseases of winter wheat. It would be exciting to study the mechanism of R. erythropolis on wheat pathogens in vitro and in planta which are still less developed in the literature.

Disease spectrum and its molecular characterisation in the lentil production system of lower-Indo Gangetic plains.

Lentil is a food legume grown in the Indo-Gangetic plains including lower Gangetic Bengal (LGB). Lentil productivity in this zone is severely impeded because of the prevalence of several biotic cues. Plausible reports regarding the status of disease scenario and the associated risk factors are missing. Therefore, judicious crop management strategies are lacking. An intensive survey of 267 farmers' fields was conducted over 3 years in major lentil-growing districts of LGB to evaluate the disease incidence and prevalence. Additional insights were generated, apprehending isolation and characterisation of associated pathogens through spore morphology and molecular markers as well as elucidating the role of biophysical factors in influencing disease development. Climate change has shifted the disease dimension of lentil and precipitated new disease complexes of great risk, which was reflected through geospatial mapping results in the present study. The prevalence of three major diseases, namely collar rot (Sclerotium rolfsii), lentil blight complex (LBC) incited by both Alternaria and Stemphylium, and lentil rust (Uromyces viciae-fabae), was ascertained through cultural and molecular studies and contextualised through pathogenicity appraisal. This study is the first to investigate the complex mixed infection of Alternaria alternata and Stemphylium botryosum, successfully isolating S. botyrosum in India, and confirming the pathogens through sequencing by using internal transcribed spacer (ITS) primers and Stemphylium-specific Glycerol-3-phosphate dehydrogenase 1 (gpd1) and gpd2 primers. Unlike late planting, early planting promoted collar rot infestation. LBC and rust incidence were magnified in late planting. Soil texture resulted in the spatial distribution of collar rot disease. The surveyed data also highlighted the potential role of resistant cultivars and cropping pattern intervention to ensure associational resistance towards addressing the disease bottleneck in lentil.

Survival models: a tool for managing and analyzing the incidence of rust in irrigated coffee trees

Studies related to the characteristics and health of coffee make it possible to manage and enhance the product, directly influencing its quality. Such studies are crucial for strategic marketing reasons, encompassing cost reduction, loss, and production optimization. In addition to these aspects, there are concerns about improving product quality. Thus, studying the variable time until the development of coffee rust, considering different irrigation systems, is relevant, given that this disease causes early leaf fall and branch drying, diminishing both production and product quality. In light of the above, the objective is to demonstrate that the main survival analysis models can be employed as instruments for managing and analyzing the incidence of coffee rust, considering different irrigation systems. The analysis revealed that the drip irrigation system was more effective than the others.

Resistance of genotypes of arabica coffee against rust on leaf of coffee plant in different locations in Province of North Sumatra, Indonesia

The most important disease in many coffee production countries is rust on the leaf of coffee plant (RLCP). RLCP epidemics indicated by severity and incidence depend on the host, location and the fungi. The purpose of this research was to study the resistance of genotypes of Arabica coffee against RLCP in different locations. A field experiment with seven genotypes of Arabica coffee in four locations in Province of North Sumatra of Indonesia was carried out using a randomized complete block design with three replications. This research revealed a significant interaction between the genotype and the location on incidence of rust on branch (IRB), incidence of rust on leaf (IRL) and severity of leaf due to rust (SLR). For IRB and IRL, the role of the location was more important than the role of the genotype. For SRL, the role of the interaction was more important than the role of the genotype and the location. Genotype GN-5 had the lowest SRL. Location-3 was not conducive to the growth and development of the fungus H. vastatrix. Pathogen races were very likely to differ between locations. Based on SRL, these pathogens were not aggressive in all locations.

Response of arabica coffee populations on coffee leaf rust in two weather conditions in North Sumatra, Indonesia

Coffee leaf rust (CLR) disease is seriously threatening the sustainability of coffee production in many countries. The incidence and severity as CLR parameters generally depend on the coffee plant, pathogen, and environment. Therefore, this study aimed to determine the effect of arabica coffee populations and weather conditions on CLR parameters. The study was carried out using a field experiment with seven groups of arabica coffee populations in different weathers in North Sumatra Province, Indonesia. The results showed that the arabica coffee population P7 from District Toba had high resistance to wet weather. Furthermore, all the population groups showed higher degree of CLR parameters in dry than wet weather, while a significant interaction between the population and the weather was observed on branch rust incidence, leaf rust incidence, and severity. Moreover, H. vastatrix races were probably varied and had different adaptability to weather changes, which was the most decisive factor for the dispersal and severity of CLR. The CLR parameters in the dry weather did not correlate with the parameters in the wet weather and vice versa. The total rainfall and the number of the rainy day reduced the CLR dispersal and severity.