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Resistance responses in the leaves of eight rose genotypes, Knock Out (highly resistant), Arka Nishkant (moderately resistant), R. multiflora (highly susceptible), Arka Swadesh (highly susceptible), IIHRR 13-4 (susceptible), Arka Parimala (susceptible), R. indica (susceptible) and IIHRR 4-15-12 (moderately susceptible), exhibiting varied levels of resistance against black spot were investigated post artificial inoculation with black spot pathogen, Diplocarpon rosae. There was consistent increase in the activities of defense related enzymes such as catalase, peroxidase, polyphenol oxidase, superoxide dismutase and phenylalanine ammonia lyase and other defense related secondary metabolites like phenols and flavonoids at different phases of black spot progression and increase was high in resistant genotypes Knock Out and Arka Nishkant. The peak activity of defense enzymes and high concentration of other metabolites was witnessed during early stages of infection in the resistant genotypes while it was during later phase in the susceptible genotypes. These results suggested that the faster and stronger activation of defense system is associated with the resistance against black spot in the rose genotypes.

The fungal pathogen, Diplocarpon rosae, infects only roses (Rosa spp.) and leads to rose black spot disease. Rose black spot is the most problematic disease of outdoor-grown roses worldwide due to the potential for rapid leaf chlorosis and defoliation. Eleven races of the pathogen were previously characterized from isolates collected in North America and Europe. Isolates of D. rosae obtained from infected leaves of the roses Brite EyesTM (‘RADbrite’; isolate BEP; collected in West Grove, PA) and Oso Easy® Paprika (‘CHEwmaytime’; isolate PAP; collected in Minneapolis, MN) proved to have unique infection patterns using the established host differential with the addition of Lemon FizzTM (‘KORlem’). The new races are designated race 12 (BEP) and race 13 (PAP), respectively, and Lemon FizzTM should be included in the updated host differential because it distinguishes races 7 and 12. Additionally, inconsistent infections and limited sporulation were found in the host differential Knock Out® (‘RADrazz’) for races 7 and 12. Expanding the collection of D. rosae races supports ongoing research efforts, including host resistance gene discovery and breeding new rose cultivars with increased and potentially durable resistance.

Two environmentally stable QTLs linked to black spot disease resistance in the Rosa wichurana genetic background were detected, in different connected populations, on linkage groups 3 and 5. Co-localization between R-genes and defense response genes was revealed via meta-analysis. The widespread rose black spot disease (BSD) caused by the hemibiotrophic fungus Diplocarpon rosae Wolf. is efficiently controlled with fungicides. However, in the actual context of reducing agrochemical use, the demand for rose bushes with higher levels of resistance has increased. Qualitative resistance conferred by major genes (Rdr genes) has been widely studied but quantitative resistance to BSD requires further investigation. In this study, segregating populations connected through the BSD resistant Rosa wichurana male parent were phenotyped for disease resistance over several years and locations. A pseudo-testcross approach was used, resulting in six parental maps across three populations. A total of 45 individual QTLs with significant effect on BSD resistance were mapped on the male maps (on linkage groups (LG) B3, B4, B5 and B6), and 12 on the female maps (on LG A1, A2, A3, A4 and A5). Two major regions linked to BSD resistance were identified on LG B3 and B5 of the male maps and were integrated into a consensus map built from all three of the male maps. A meta-analysis was used to narrow down the confidence intervals of individual QTLs from three populations by generating meta-QTLs. Two 'hot spots' or meta-QTLs were found per LG, enabling reduction of the confidence interval to 10.42 cM for B3 and 11.47 cM for B5. An expert annotation of NBS-LRR encoding genes of the genome assembly of Hibrand et al. was performed and used to explore potential co-localization with R-genes. Co-localization with defense response genes was also investigated.

As tecnologias de inteligência artificial (ia) estão permitindo identificar com mais precisão doenças em folhas de plantas por meio da análise de imagens, com efeitos benéficos sobre a agricultura (custo, eficiência, qualidade). O artigo apresenta os resultados de estudos desenvolvidos com o uso de três tecnologias (plataformas) distintas treinadas com o mesmo conjunto de 50 imagens de quatro doenças, indicando as características visuais de cada uma delas. O treinamento foi dividido em duas etapas: a primeira realizada com 30 imagens e a segunda com 20 imagens, e a validação e a análise do aprendizado foram realizadas a partir de 10 imagens. O propósito dos testes é comparar a assertividade de reconhecimento das doenças em cada tecnologia/plataforma. As doenças examinadas para o estudo são: Peronospora (downy mildew), Diplocarpon rosae (black spot), Oídio (powdery mildew) e Cancro cítrico. Os resultados mostraram-se positivos para a identificação das doenças por meio de imagens.Palavras-chave: Aprendizado de Máquinas. Agricultura Digital. Imagens Digitais. api. Visão Computacional.

The haploid ascomycete Diplocarpon rosae is the causal agent of black spot disease on roses, a widespread and devastating disease in the outdoor landscape. In this study, we established a Eurasian collection of 77 monoconidial strains of D. rosae: 50 strains collected on cultivated roses in Europe and Asia, and 27 strains on wild roses in Kazakhstan. To provide tools to describe its biology and to study its genetic diversity, we sequenced two strains of D. rosae using Illumina paired-end technology. The genome sizes of these two strains were estimated at 31.1 and 35.2 Mb, which are two times smaller than the genome size of the unique strain previously published. A BUSCO analysis confirmed a genome duplication of the strain previously sequenced and partial gene duplication of strains analysed in this study. Using the two genome sequences, 27 polymorphic microsatellite markers were identified. Polymorphism analysis of the 77 strains revealed a strong genetic differentiation between strains from cultivated and wild roses, and a lower diversity within the fungal population from cultivated roses compared to the population from wild roses. Pathogenicity of 10 strains was evaluated on 9 rose cultivars inoculated in the greenhouse. Disease scoring allowed the classification of strains into three groups and the characterization of resistance of rose cultivars. Good correlation observed between resistance scoring in greenhouse conditions and in the field indicates that pathogenicity assays in controlled conditions could be very useful in the near future to rapidly characterize the resistance of new rose varieties to black spot disease., This work was supported by the CASDAR no. C-2014-06 from the French Ministry of Agriculture, Agrifood and Forestry. The authors thank Markus Linde for kindly supplying German infected leaves, Célia Calmels for microsatellite analysis, Sandrine Pierre for the contribution to assays on whole plants, Phenotic and Experimental unit Horticole for plant management in the greenhouse and in the field, respectively, Thibault Leroy for reads assembly of the Kazakh strain, and Biogenouest for read assembly of the German strain. All microsatellite data were obtained on the ANAN platform (M. Bahut). This work was financially supported by SFR 4207 Quasav.

Black spot disease, which is caused by the ascomycete Diplocarpon rosae, is the most severe disease in field-grown roses in temperate regions and has been distributed worldwide, probably together with commercial cultivars. Here, we present data indicating that muRdr1A is the active Rdr1 gene, a single-dominant TIR-NBS-LRR (Toll/interleukin-1 receptor-nucleotide binding site-leucine rich repeat) (TNL)-type resistance gene against black spot disease, which acts against a broad range of pathogenic isolates independent of the genetic background of the host genotype. Molecular analyses revealed that, compared with the original donor genotype, the multiple integrations that are found in the primary transgenic clone segregate into different integration patterns in its sexual progeny and do not show any sign of overexpression. Rdr1 provides resistance to 13 different single-spore isolates belonging to six different races and broad field mixtures of conidia; thus far, Rdr1 is only overcome by two races. The expression of muRdr1A, the active Rdr1 gene, leads to interaction patterns that are identical in the transgenic clones and the non-transgenic original donor genotype. This finding indicates that the interacting avirulence (Avr) factor on the pathogen side must be widespread among the pathogen populations and may have a central function in the rose-black spot interaction. Therefore, the Rdr1 gene, pyramided with only a few other R genes by sexual crosses, might be useful for breeding roses that are resistant to black spot because the spread of new pathogenic races of the fungus appears to be slow.

As a result of the study of the efficacy of using biopharmaceuticals against black maculation of leaves Roses found that effectiveness of investigated of biological products during the growing season of the genus Rosa L. is 56.4±16.3% in the range from 21.1 to 72.3%. Thus, the highest values of protective action against black maculation of leaves roses had: Tryhopsyn (Pseudomonas and Trichoderma 6×109 CFU/cm3) – 72.8%, Tryhodermin BT (a.s. Trichoderma viride, titer of 2×109 CFU/cm3)+Planryz BT (a.s. Ps. fluorescens 5×109 CFU/cm3) (1:1) and Tryhodermin BT (a.s. Trichoderma viride, titer of 2×109 CFU/cm3) + Haupsyn BT (a.s. Ps. aureofaciens 5×109 CFU/cm3) (1:1) to 72.3%, Planryz BT (a.s. Ps. fluorescens 5×109 CFU/cm3) – 65.3%. Biologicals is restrain the development of pathology caused by causative agent Diplocarpon rosae F.A. Wolf on a variety of different groups of the genus Rosa L., namely the indicator of damage index in the samples of the group of Hybrid tea roses Kardinal 85 Kordes, Germany (1985) was 18.2%, climbing New Dawn Somerset Rose Nursery, USA (1930) by 2.2%, floribunda Leonardo da Vinci Meilland (1993) by 6.2%, English Abraham Darby Austin, United Kingdom (1985) by 6.7% less than without processing.

Black spot disease caused by the hemibiotrophic ascomycete Diplocarpon rosae is the most devastating disease of field-grown roses. Although resistance to black spot is an important trait for rose breeding, little information on the diversity of the pathogen is currently available. To date, a number of single-spore isolates have been characterized based on a set of test genotypes of the host. In this study, six polymorphic simple sequence repeat (SSR) markers for D. rosae were developed and their potential application to single-spore isolates collected from a wide range of geographic locations within and outside Europe discussed. Populations of the fungus were then analysed in different German rose collections/populations. Gene diversity was highest in older rose collections managed without fungicide application, and lowest in the two- to three-year-old testing sites of German rose breeders. Additional analyses of a global collection of single samples and populations revealed no unique alleles from any of the locations, indicating that global trading of rose varieties has led to an admixture of the pathogen.

Fungicides were evaluated for their efficacy against black spot of rose, caused by Diplocarpon rosae, when applied during winter months to hybrid tea rose plants in two studies. One study, conducted at two Auburn University campus sites, consisted of applications of horticultural oil, chlorothalonil plus an antitranspirant, and cyproconazole, along with nontreated plants; one site included triforine applications. Rose canes were treated two and three times between late October and February in 1996-97 and 1997-98, respectively; then plants were examined every 2 to 4 days beginning in mid-February for onset of symptoms of black spot. In both years, winter applications of fungicides (chlorothalonil, cyproconazole, and triforine) delayed disease onset compared with treatments without fungicides (nontreated and oil applications). Decreased plant defoliation, as well as improved plant vigor, were observed through the 1998 growing season following fungicidal winter treatments at campus sites; winter treatments with oil did not suppress disease compared with no treatment. In a second study started in November 1997, at a site near Shorter, AL, three systemic fungicides (myclobutanil, cyproconazole, and triforine) were applied to rose canes during the winter; nontreated plants were included. Decreased disease symptoms and defoliation of rose plants were observed early in the 1998 and 1999 seasons following winter applications of cyproconazole and triforine compared with myclobutanil or nontreated plants. Winter treatments with these fungicides did not consistently provide season-long reduction of black spot. However, season-long plant vigor and flower production on plants were improved at the Shorter site following winter applications of any of the above systemic fungicides compared with nontreated plants.

Key message: Transcriptomic analysis resulted in the upregulation of the genes related to common defense mechanisms for black spot and the downregulation of the genes related to photosynthesis and cell wall modification for powdery mildew. Abstract: Plant pathogenic fungi successfully colonize their hosts by manipulating the host defense mechanisms, which is accompanied by major transcriptome changes in the host. To characterize compatible plant pathogen interactions at early stages of infection by the obligate biotrophic fungus Podosphaera pannosa, which causes powdery mildew, and the hemibiotrophic fungus Diplocarpon rosae, which causes black spot, we analyzed changes in the leaf transcriptome after the inoculation of detached rose leaves with each pathogen. In addition, we analyzed differences in the transcriptomic changes inflicted by both pathogens as a first step to characterize specific infection strategies. Transcriptomic changes were analyzed using next-generation sequencing based on the massive analysis of cDNA ends approach, which was validated using high-throughput qPCR. We identified a large number of differentially regulated genes. A common set of the differentially regulated genes comprised of pathogenesis-related (PR) genes, such as of PR10 homologs, chitinases and defense-related transcription factors, such as various WRKY genes, indicating a conserved but insufficient PTI [pathogen associated molecular pattern (PAMP) triggered immunity] reaction. Surprisingly, most of the differentially regulated genes were specific to the interactions with either P. pannosa or D. rosae. Specific regulation in response to D. rosae was detected for genes from the phenylpropanoid and flavonoid pathways and for individual PR genes, such as paralogs of PR1 and PR5, and other factors of the salicylic acid signaling pathway. Differently, inoculation with P. pannosa leads in addition to the general pathogen response to a downregulation of genes related to photosynthesis and cell wall modification. © 2019, The Author(s).

RESUMO O objetivo deste trabalho foi verificar o potencial de extratos oriundos de plantas medicinais (Rosmarinus officinalis L., Equisetum arvense L. e Moringa oleifera Lam.) e produtos comerciais (a base de extratos vegetais, óleos vegetais e fosfito de potássio) no controle in vitro de Diplocarpon rosae. Avaliou-se o efeito dos tratamentos sobre o fitopatógeno pelo índice de velocidade de crescimento micelial, inibição do crescimento micelial, inibição da esporulação, índice de esporulação, síntese de proteínas, a atividade específica de peroxidase e catalase no micélio do fitopatógeno, utilizando extrato bruto aquoso (EBA) de folhas de R. officinalis (1%); EBA de caules de E. arvense (1%); EBA de sementes de M. oleifera (1%); produto comercial a base de extratos vegetais fermentados (0,01%); produto comercial a base de fosfito de potássio (0,01%); produto comercial a base de óleos vegetais (0,01%); produto a base de massa cítrica (0,01%); fungicida a base de Tiofanato metílico (0,007%); adjuvante (0,0025%) BDA e BD. Pelos resultados observou-se maior redução do crescimento de D. rosae quando na presença do produto comercial a base de óleos vegetais. O EBA de E. arvense e o produto comercial a base de extratos vegetais fermentados apresentaram efeito anti-esporulante. Os tratamentos com EBA de R. officinalis, EBA de E. arvense, EBA de M. oleifera, produto comercial a base de óleos vegetais e produto a base de massa cítrica aumentaram a síntese de proteínas no micélio D.rosae. Houve aumento da atividade específica das enzimas peroxidase e catalase no micélio quando na presença do EBA de R. officinalis e produto comercial a base de fosfito de potássio, respectivamente. O EBA de E. arvense, e os produtos comerciais a base de óleos vegetais e a base de extratos vegetais fermentados, apresentaram resultados promissores no controle do fitopatógeno D. rosae. ABSTRACT The aim of this study was to verify the potential of extracts derived from medicinal plants (Rosmarinus officinalis L., Equisetum arvense L. and Moringa oleifera Lam.) and commercial products (based on plant extracts, plant oil and potassium phosphite) on the in vitro control of Diplocarpon rosae. The effect of treatments on the phytopathogen was evaluated according to the mycelial growth speed rate, mycelial growth inhibition, sporulation inhibition, sporulation rate, protein synthesis, and peroxidase and catalase specific activity on the mycelium of the phytopathogen, using aqueous crude extract (ACE) of R. officinalis leaves (1%); ACE of E. arvense stems (1%); ACE of M. oleifera seeds (1%); commercial product based on fermented plant extracts (0.01%); commercial product based on potassium phosphite (0.01%); commercial product based on plant oil (0.01%); product based on citrus mass (0.01%); fungicide based on thiophanate methyl (0.007%); and adjuvant (0.0025%) in PDA and PD media. Results showed a higher reduction in the growth of D. rosae in the presence of commercial product based on plant oils. The ACE of E. arvense and the commercial product based on fermented plant extracts exhibited anti-sporulant effect. Treatments with ACE of R. officinalis, ACE of E. arvense, ACE of M. oleifera, commercial product based on plant oil and product based on citrus mass increased protein synthesis in D. rosae mycelium. There was increased specific activity of the enzymes peroxidase and catalase in the mycelium in the presence of ACE of R. officinalis and commercial product based on potassium phosphite, respectively. The ACE of E. arvense and the commercial products based on plant oils and fermented plant extracts showed promising results in the control of the phytopathogen D. rosae.

Rose black spot, caused by Diplocarpon rosae, is one of the most devastating foliar diseases of cultivated roses (Rosa spp.). The globally distributed pathogen has the potential to cause large economic losses in the outdoor cultivation of roses. Fungicides are the primary method to manage the disease, but are often viewed unfavorably by home gardeners due to potential environmental and health impacts. As such, rose cultivars with genetic resistance to black spot are highly desired. The tetraploid climbing rose Brite EyesTM (‘RADbrite’) is known for its resistance to black spot. To better characterize the resistance present in Brite EyesTM, phenotyping was conducted on a 94 individual F1 population developed by crossing Brite EyesTM to the susceptible tetraploid rose ‘Morden Blush’. Brite EyesTM was resistant to all D. rosae races evaluated except for race 12. The progeny were either resistant or susceptible to all races (2, 3, 8, 9, 10, 11, and 13) evaluated. The segregation ratio was 1:1 (χ2 = 0.3830, P = 0.5360) suggesting resistance is conferred by a single locus. The roses were genotyped with the WagRhSNP 68K Axiom array and the ‘polymapR’ package was used to construct a map. A single resistance locus (Rdr4) was identified on the long arm of chromosome 5 homoeolog 4. Three resistance loci have been previously identified (Rdr1, Rdr2, and Rdr3). Both Rdr1 and Rdr2 are located on a chromosome 1 homoeolog. The chromosomal location of Rdr3 is unknown, however, races 3 and 9 are virulent on Rdr3. Rdr4 is either a novel gene or an allele of Rdr3 as it provides resistance to races 3 and 9. Due to its broad resistance, Rdr4 is an excellent gene to introgress into new rose cultivars.

Rose black spot is one of the most severe diseases of field-grown roses. Though R-genes have been characterised, little information is known about the molecular details of the interaction between pathogen and host. Based on the recently published genome sequence of the black spot fungus, we analysed gene models with various bioinformatic tools utilising the expression data of infected host tissues, which led to the prediction of 827 secreted proteins. A significant proportion of the predicted secretome comprises enzymes for the degradation of cell wall components, several of which were highly expressed during the first infection stages. As the secretome comprises major factors determining the ability of the fungus to colonise its host, we focused our further analyses on predicted effector candidates. In total, 52 sequences of 251 effector candidates matched several bioinformatic criteria of effectors, contained a Y/F/WxC motif, and did not match annotated proteins from other fungi. Additional sequences were identified based on their high expression levels during the penetration/haustorium formation phase and/or by matching known effectors from other fungi. Several host genotypes that are resistant to the sequenced isolate but differ in the R-genes responsible for this resistance are available. The combination of these genotypes with functional studies of the identified candidate effectors will allow the mechanisms of the rose black spot interaction to be dissected.

Environmental conditions in Florida are favorable for the development and persistence of insects and diseases that affect rose (Rosa sp.) plants, necessitating periodic applications of pesticides to maintain plant appearance. In addition, nutrient-deficient and well-drained soils in Florida force gardeners to provide supplemental fertilizer and water. Landscape performance is rarely considered for the development of new rose cultivars; consequently, careful selection of cultivars adapted to local conditions is necessary to reduce maintenance. The objective of this study was to develop recommendations of own-root, low-maintenance roses among 11 old garden and modern cultivars for central Florida. Plants were provided with minimal amounts of water and fertilizer, no control for diseases and insects, and no grooming or deadheading. Weekly evaluations were performed on all plants for plant quality, flower coverage; and incidence of black spot (caused by Diplocarpon rosae), cercospora leaf spot (caused by Cercospora rosicola), and foliar damage [caused by chilli thrips (Scirtothrips dorsalis)]. Damage caused by the foliar diseases and chilli thrips were the major factors that affected plant quality, vigor, and subsequently, flower production. Differences in susceptibility to these three factors were found among cultivars, enabling the classification of the 11 cultivars as recommended, cautiously recommended, and not recommended for central Florida. After two years, ‘Mrs. B.R. Cant’ appeared to be the most suited for central Florida as plant quality and flower production were fairly constant. ‘Duchesse de Brabant’, ‘RADrazz’ (Knock Out®), and ‘Spice’ were the next best performers and are cautiously recommended for central Florida. These cultivars were minimally affected by both diseases, showing low severity of yellowing and defoliation nor a decline in flower production. “Bailey Red”, ‘Old Blush’, ‘Belinda’s Dream’, ‘Perle d’Or’, ‘BUCbi’ (Carefree Beauty™), ‘Mutabilis’, and ‘WEKcisbako’ (Home Run®) had severe defoliation, poor growth, and low vigor in this study and do not appear to be low-maintenance landscape roses for central Florida.

Le rosier est une des plus importantes espèces ornementales de par le monde. Sa valeur esthétique est dépendante d’un niveau de sensibilité aux maladies notamment foliaires dont les plus fréquentes sont la maladie des taches noires et l’oïdium. Les obtenteurs, pépiniéristes et consommateurs s’orientent de plus en plus vers l’utilisation de variétés résistantes à ces maladies. Ainsi, afin de mieux comprendre ces maladies et de développer des outils de sélection, des tests d’infection en conditions contrôlées et des études de déterminisme génétique de la résistance/sensibilité sont nécessaires. Les essais en conditions contrôlées sur oïdium ont été difficiles à conduire du fait des difficultés à multiplier et à conserver le champignon (Podosphaera pannosa) alors que plusieurs essais sur la maladie des taches noires (Diplocarpon rosae) ont été mis en place. Des études génétiques ont été menées sur une population interspécifique permettant de mettre en évidence l’existence de trois QTLs potentiels pour la résistance à la maladie des taches noires et un QTL majeur pour la résistance à l’oïdium. L’obtention récente de la séquence du génome du rosier devrait permettre d’identifier l’existence de gènes de résistance au niveau de ces QTLs. Toutefois, des analyses plus approfondies devront être menées afin d’identifier le(s) gène et/ou la(es) séquence(s) responsable(s) des interactions mises en évidence dans ce projet., Roses are one of the most important ornamental crops in the world. Its esthetical value is closely linked with the resistance against the major foliar diseases, i.e. black spot disease and powdery mildew. As the cosmetic appearance of an ornamental plant is key to its marketability and consumer acceptance, a high degree of pest/disease resistance is required for the rose. To aim to understand the genetic control of disease resistance and to develop breeding tools, development of assays under controlled conditions and genetic determinism studies of the resistance/susceptibility are necessary. The assays on powdery mildew have been challenging to conduct due to the difficulty to preserve and produce the pathogen (Podosphaera pannosa) while the same tests were successfully developed for the black spot disease (Diplocarpon rosae). The interspecific population genetic studies made it possible to identify three QTLs governing the black spot resistance and one for powdery mildew resistance. The recent available rose genome could be an opportunity to identify genes under the QTLs. Nevertheless, some comprehensive studies have to be conducted to clearly detect the identified genes under these QTLs.

Black spot disease has become a serious constraint for successful cultivation of rose crop in Pakistan and rest of the world. The current research was conducted to identify the causal pathogen and respective disease severity in 4 districts of province Punjab, Pakistan. The most prominent symptoms of disease included formation of purple to black spot (5-15 mm) with/without yellow margins especially on older leaves. Mortality of infected plants was also observed in severely infected plants. It was observed that Diplocarpon rosae was the casual organism of this disease. The greenhouse experiment revealed variation in pathogenicity of different pathogenic strains.

The objective of this study was to evaluate the potential of extracts derived from medicinal plants (Rosmarinus officinalis, Equisetum arvense and Moringa oleifera) and commercial products (based on plant extracts, vegetable oils and potassium phosphite) in vitro control and greenhouse of Diplocarpon rosae and evaluate through resistance induction of determining the specific activity of oxidative enzymes, catalase and polyphenol in phytopathogen and roses. In vitro evaluated the effect of treatments on the pathogen by mycelial growth rate index, inhibition of mycelial growth inhibition of sporulation, sporulation rate, protein synthesis, peroxidase and catalase specific activity using aqueous crude extract (ACE) to R. officinalis leaves (1%); ACE E. arvense stem (1%); ACE M. oleifera seeds (1%); commercial product based on fermented plant extracts (0.01%); commercial product based on potassium phosphite (0.01%); commercial product based on vegetable oils (0.01%); Ecolife® (0.01%); Thiophanate methyl fungicide basis (0.007%); adjuvant (0.0025%) on potato dextrose agar (PDA) and potato dextrose (BD). Under greenhouse conditions were evaluated incidence and severity of disease black spot, productivity (number of buttons), biometrics (length buttons, length and stem thickness), chlorophyll content and peroxidase, catalase and polyphenol oxidase specific activity, using the same treatments with ten times higher doses and the control was distilled water. In vitro results with commercial product based on vegetable oils 56% reduced mycelial growth; ACE E. arvense and commercial product based on fermented plant extracts inhibited 81 and 75% sporulation. The treatments with ACE R. officinalis, E. arvense, M. oleifera, commercial product based on vegetable oils and Ecolife® increased protein synthesis in D.rosae mycelium. Also in the mycelium was increased specific activity of peroxidase and catalase in ACE R. officinalis and commercial product based on potassium phosphite, respectively. In a greenhouse the largest stem length was observed in the treatment with the commercial product based on potassium phosphite and the greatest thickness of the stem in the three commercial products. The highest enzyme activities were observed in the peroxidase enzyme with a commercial product based on potassium phosphite in the first application, catalase, ACE M. oleifera and potassium phosphite on first application and polyphenol with ACE R. officinalis and M. oleifera in the third application. Natural products can be used in disease control blight and resistance induction, showing promising results. O objetivo deste trabalho foi verificar o potencial de extratos oriundos de plantas medicinais (Rosmarinus officinalis, Equisetum arvense e Moringa oleifera) e produtos comerciais (a base de extratos vegetais, óleos vegetais e fosfito de potássio) no controle in vitro e em casa de vegetação de Diplocarpon rosae e avaliar a indução de resistência por meio da determinação da atividade específica das enzimas peroxidase, catalase e polifenoloxidase no fitopatógeno e em roseiras. In vitro avaliou-se o efeito dos tratamentos sobre o fitopatógeno pelo índice de velocidade de crescimento micelial, inibição do crescimento micelial, inibição da esporulação, índice de esporulação, síntese de proteínas, atividade específica de peroxidase e catalase utilizando extrato bruto aquoso (EBA) de folhas de R. officinalis (1%); EBA de caules de E. arvense (1%); EBA de sementes de M. oleifera (1%); produto comercial a base de extratos vegetais fermentados (0,01%); produto comercial a base de fosfito de potássio (0,01%); produto comercial a base de óleos vegetais (0,01%); Ecolife® (0,01%); fungicida a base de Tiofanato metílico (0,007%); adjuvante (0,0025%) e meio batata dextrose ágar (BDA testemunha) e batata-dextrose (BD testemunha). Em casa de vegetação foram avaliadas incidência e severidade da doença pinta preta, produtividade (número de botões), biometria (comprimento de botões, comprimento e espessura de haste), teor de clorofila e atividade específica de peroxidase, catalase e polifenoloxidase, utilizando os mesmo tratamentos com as doses dez vezes maiores, e a testemunha foi água destilada. O resultado in vitro com produto comercial a base de óleos vegetais reduziu 56% o crescimento micelial; EBA de E. arvense e produto comercial a base de extratos vegetais fermentados inibiram 81 e 75% a esporulação. Os tratamentos com EBA de R. officinalis, EBA de E. arvense, EBA de M. oleifera, produto comercial a base de óleos vegetais e Ecolife® aumentaram a síntese de proteínas no micélio D.rosae. Também no micélio houve aumento da atividade específica das enzimas peroxidase e catalase, no EBA de R. officinalis e produto comercial a base de fosfito de potássio, respectivamente. Em casa de vegetação o maior comprimento de haste foi observado no tratamento com produto comercial a base de fosfito de potássio e a maior espessura da haste nos três produtos comerciais. As maiores atividades específicas foram observadas na enzima peroxidase com produto comercial a base de fosfito de potássio na primeira aplicação, catalase, com EBA de M. oleifera e fosfito de potássio, na primeira aplicação e polifenoloxidase com EBA de R. officinalis e M. oleifera na terceira aplicação. Com os resultados observados, verifica-se que os produtos naturais podem ser utilizados no controle da doença pinta preta e na indução de resistência, apresentando resultados promissores. ix, 54 f

Biostimulants are classified as materials that are neither a fertilizer nor a pesticide, but when applied to a plant will enhance their health, growth, and protection. Manufacturers claim biostimulants have underexploited potential in providing protectant properties to plants against pathogen attack. This study evaluated the efficacy of seven commercially available biostimulants against the foliar pathogens Guignardia aesculi, leaf blotch of horsechestnut (Aesculus hippocastanum L.) and Diplocarpon rosae black spot of roses (Rosa “Pretty Polly”). None of the biostimulant products tested in this investigation achieved a sufficient degree of pathogen control to warrant replacement of or supplementation with conventional synthetic fungicides.

Several diseases caused by Botrytis cinerea were found on different ornamented plants at the Kanagawa Prefectural Ofuna Botanical Garden, in Japan. Gray mold was first reported on the four of those plant species, such as bougainvillea, and French marigold was added in the new host record of B. cinerea. The pathogenicity of the fungus in the four plants such as Campanula sp., previously unreported, was confirmed based on our inoculation tests. In addition, we revealed several new host ranges of some pathogenic fungi: Twenty one plant species were reported as new host of Diplocarpon rosae (anamorph: Marssonina rosae).

Regional, replicated cultivar trials of landscape roses are an ongoing component of the Earth-Kind® program, which was started at Texas A&M University in the 1990s to support environmental landscape stewardship. The rose trials within the Earth-Kind program identify and promote the most regionally adapted rose cultivars and are conducted without fertilizers or pesticides and greatly reduced irrigation. Black spot (caused by Diplocarpon rosae Wolf) is the most serious disease of outdoor-grown roses worldwide as a result of the potential for rapid leaf yellowing and defoliation. Earth-Kind designated cultivars for the south–central United States and roses under trial in other regions or considered for future Earth-Kind trials (n = 73 roses) and two susceptible control cultivars were challenged with North American Races 3, 8, and 9 of D. rosae, which were previously characterized at the University of Minnesota. Young expanded leaves were inoculated using detached leaf assays. Lesion length (LL) was measured for susceptible reactions and cultivar ploidy was determined using root tip squashes. Diploid, triploid, and tetraploid cultivars (n = 20, 30, and 23, respectively) were identified, and race-specific resistances and partial resistances were also identified. Race-specific resistance was generally more prevalent in newer rose cultivars and rose cultivars more recently included in Earth-Kind trials. Nine cultivars were resistant to all three races (Brite Eyes™, ‘Grouse’, Home Run®, Knock Out®, Paprika™, Peachy Cream™, Pink Knock Out®, Rainbow Knock Out®, and Yellow Submarine™). Blushing Knock Out®, a sport of Knock Out®, was susceptible to Race 8. Partial resistance rank for LL was generally consistent across races for roses susceptible to multiple races. The application of these data includes: characterizing the minimum resistance level needed for roses to warrant inclusion in Earth-Kind field trials, the identification of additional race-specific resistance genes, identifying resistance-breaking isolates of D. rosae, understanding race composition in field trials based on infection patterns of key cultivars, selection of parents for resistance breeding efforts, and continued comparisons between LL and growing bodies of Earth-Kind field resistance data.

Black spot of rose is distributed throughout the world and is the most serious disease of roses (Rosa spp.) in the outdoor landscape. Resistance breeding has been frustrated by the occurrence of races of the causal pathogen Diplocarpon rosae. Races from Germany, North America and the UK have been characterized and maintained in a pathogenic state. However, these races were characterized using independent sets of host genotypes and are referenced using different nomenclatures. In the present study, a total of 15 D. rosae isolates from these locations, as well as Belgium and Italy, were inoculated to a common set of 15 rose cultivars in replicated, detached leaf trials. Baby LoveTM (cv. Scrivluv) was resistant to all isolates except for one originating from the UK. The rose cultivars Mrs Doreen Pike (Ausdor) and Hansa were resistant to all isolates except for one originating from Minnesota, USA. No rose genotype was universally susceptible. A total of 11 pathogenic races were differentiated based on their unique host ranges and were assigned an international race nomenclature. Nine cultivars are proposed as the first standard set of differential genotypes for characterization of D. rosae races.

The interactions of four pathotypes of Diplocarpon rosae with 34 species and hybrids of Rosa were compared in an ongoing search for criteria of potential relevance to rose breeding. There were greater similarities in the resistance-susceptibility interactions of these roses to the pathotypes DA1, CW1 and ZM1, than to a fourth pathotype, DA2. Among the species roses, only those of the section Cinnamomeae were susceptible to DA2 and this susceptibility was transmitted in several cases to hybrid progeny. CW1 had the greatest pathogenicity of the four pathotypes. In a cross between R. rugosa cv. Scabrosa, which was resistant and R. rugosa f. alba, which was susceptible to all pathotypes, the progeny were tested for resistance to pathotypes DA1, CW1 and ZM1. Each of the 20 progeny was susceptible to all three pathotypes. This shows that, unlike the well characterized Rdr1 gene for resistance to D. rosae, the resistance of R. rugosa cv. Scabrosa is not determined by a dominant major gene. The diploid hybrid, R. rugosa cv. Martin Frobisher × cv. Mistress Quickly, was resistant to all four pathotypes, but an induced tetraploid of this hybrid was susceptible to all pathotypes. The relevance of these findings to the breeding of roses for resistance to black spot disease is discussed.

Black spot disease, incited by the fungus Diplocarpon rosae Wolf, is the most important disease of roses (Rosa hybrida L.) in the outdoor landscape. Though partial resistance exists in cultivated germplasm, the genetic basis of this trait has not yet been elucidated. Six diploid and six tetraploid rose cultivars were crossed in two factorial combining ability arrays. Whole plant and detached leaf inoculation methods were used to assess partial resistance under two different disease pressures using a characterized single-spore isolate. Parents from both arrays had significant general combining ability effects across multiple inoculation methods and environments. Specific combining ability was not significant for either array. Parent per se performance was highly correlated with progeny performance on a family mean basis. High positive correlations among whole plant and detached leaf inoculation methods indicate that detached leaf assays can substitute for whole plant assays. Based on these results, a breeding strategy including parental selection and early, among-family selection is proposed. To our knowledge, this is the first investigation of combining ability for disease resistance in rose.

Recently, roses (Rosa spp.) that require relatively little maintenance have gained in popularity in the United States. One group of these roses is the Griffith Buck roses, which were selected to survive the extremely cold winters of the north-central United States. Many of these roses were rated qualitatively as having disease resistance when they were released, but their resistance levels to black spot (Marssonina rosae) have not been quantified, compared with each other, or rated against other resistant or susceptible roses. In a field trial in Iowa in 2005 and 2006, 24 Griffith Buck roses that were originally described as disease resistant were compared with susceptible and resistant control cultivars for susceptibility to black spot. No fungicides were applied in either year. Plants were rated five times each year for black spot incidence, and also to assess overall plant appearance. Griffith Buck roses ‘Carefree Beauty’, ‘Aunt Honey’, ‘Honeysweet’, ‘Earthsong’, and ‘Pearlie Mae’ had significantly less black spot than many of the other cultivars. In addition, these cultivars also remained attractive and could be used in low-maintenance landscapes in the north-central United States, even under moderate black spot pressure.