First Report of Botryosphaeria dothidea on Mangifera indica L. in Gujarat

A leaf spot disease was observed on Mangifera indica L. located in the region of Rajkot, Gujarat, India. The symptoms included the appearance of small, circular to oval dark brown necrotic sunken spots on the leaves. The fungus formed grey to dark grey on potato dextrose agar and conidia were single‐celled, ovoid or oblong. On the basis of mycological characteristics, pathogenicity test and molecular identification using 28S rDNA sequence and internal transcribed spacer (ITS), the fungus was identified as Botryosphaeria dothidea. To the best of our knowledge, this is the first report of leaf spot on M. indica tree caused by Botryoshaeria dothidea in Gujarat, India.     

Identification and Characterization of Paraphoma chrysanthemicola Causing Leaf Spot Disease on Atractylodes japonica in China

Atractylodes japonica is a perennial herb in Compositae family, which is used for stomach disorders as a traditional Chinese medicine (Guo et al. 2006 ). In 2013, a leaf spot disease was first observed on plants of A. japonica in a production field of Fushun County, Liaoning Province, China. The disease had a speckled appearance initially. Lesions with grey–white centre and brown margin gradually developed and enlarged. Eventually, infections usually caused yellowing of the leaves and premature defoliation. The causal agent of infection on plants was identified as Paraphoma chrysanthemicola based on morphological and cultural characteristics, pathogenicity tests and phylogenetic analysis. To our knowledge, this is the first report of a leaf spot disease on A. japonica caused by P. chrysanthemicola in China.     

Identification of Alternaria tenuissima causing brown leaf spot on Paris polyphylla var. chinensis in China

Severe brown leaf spot disease was observed on Paris polyphylla var. chinensis in Sichuan Province, China, in 2017 and 2018. The initial symptoms were many light‐brown small spots with necrotic centres, round or irregular in shape, becoming dark brown, gradually enlarging and eventually coalescing, causing extensive leaf senescence. A fungus was isolated from diseased leaves showing typical symptoms of brown leaf spot. The isolates were cultured on potato sucrose agar, and their morphological characteristics of the causal pathogen were observed under a light microscope. Pathogenicity tests revealed that this fungus was the causal pathogen of the disease. Molecular analyses of the sequences of the ribosomal DNA internal transcribed spacer (ITS) region, translation elongation factor 1‐alpha (TEF) and the RNA polymerase II second largest subunit (RBP2) gene were conducted to confirm the identity of the pathogen. The multi‐gene phylogeny indicated that the causal agent was Alternaria tenuissima. To our knowledge, this is the first report of A. tenuissima causing brown leaf sports on P. polyphylla var. chinensis in China.     

Leaf Spot on Sweet Potato (Ipomoea batatas) Caused by Stemphylium solani,a New Disease in China

During 2010–2011, a severe leaf spot disease of sweet potato (Ipomoea batatas) was found in Haikou City, Hainan province of China. The disease is characterized with large, irregular, brown, necrotic lesions on the margin or in the centre of leaves. A species of Stemphylium was consistently recovered from pieces of symptomatic tissues on PDA. Based on morphological characteristics and molecular identification by rDNA‐ITS gene analysis, the fungal species was identified as Stemphylium solani Weber, and its pathogenicity was confirmed by Koch's postulates. This is the first report of leaf spot on sweet potato caused by S. solani in China.     

First Report of Myrothecium roridum Causing Leaf Spot on Anthurium andraeanum in China

A new severe disease on Anthurium andraeanum Lind. was observed in the summer of 2011 in Beijing, China. The fungus was isolated from symptomatic leaves, and its pathogenicity was confirmed. Based on the morphological characteristics and molecular analysis, the pathogen was identified as Myrothecium roridum Tode ex Fr. This is the first report of M. roridum causing leaf spot on A. andraeanum in China.     

New Host Record of Myrothecium roridum Causing Leaf Spot on Abutilon megapotamicum from China

During September 2010, Abutilon megapotamicum plants with dark‐brown concentric spots on leaves were observed in a commercial glasshouse located in Beijing, China. This study was carried out to identify the causal agent of this disease based on Koch's postulates and morphological characteristics. Pathogenicity tests in the glasshouse showed that Myrothecium roridum Tode ex Fr. caused the leaf spot on A. megapotamicum plants, which were the same as those observed in naturally infected plants in the field. Moreover, to confirm the pathogen to species, the rDNA internal transcribed spacer (ITS) of isolate was PCR‐amplified using ITS1 and ITS4 primer pairs and sequenced. DNA analysis revealed a 100% species identity index for M. roridum. To the best of our knowledge, this is the first report of M. roridum on A. megapotamicum in China.     

Identification of the New Pathogen (Stemphylium lycopersici) Causing Leaf Spot on Pepino (Solanum muricatum)

Pepino (Solanum muricatum var. pepino) plants were found affected by an extensive leaf spot caused by plant pathogenic fungi during a survey in the Cameron highlands, Pahang state, Malaysia. Symptomatic leaf samples were collected from infected pepino plants and cultivated on PDA medium, and the pathogen was isolated and purified; then, consequently, all isolates were identified as Stemphylium lycopersici on the basis of their cultural and morphological characteristics and combined sequences of the internal transcribed spacer (ITS) and glyceraldehyde‐3‐phosphate dehydrogenase (gpd) regions. A pathogenicity assay on detached leaves further confirmed that S. lycopersici causes leaf spot disease. To the best of our knowledge, this is the first report of S. lycopersici causing leaf spot on pepino in Malaysia and worldwide.     

Effect of Zinc on the Development of Brown Spot in Rice

Brown spot, caused by the fungus Bipolaris oryzae, is one of the most destructive diseases of rice. This study investigated the effect of zinc rates on the development of brown spot in rice. Rice plants (cv. ‘Metica‐1′) were grown in hydroponic culture amended with Zn rates (applied as ZnSO₄^.7H₂O) of 0, 0.5, 1, 2 and 4 μm and inoculated with B. oryzae. The foliar concentration of Zn was determined. Leaf samples were assessed for disease severity, and then, area under brown spot progress curve (AUBSPC) was calculated. The relationship between Zn concentrations on leaf tissues and the rates of this micronutrient was best described by a positive linear regression model, while the relationship between the Zn rates and the AUBSPC was best described with a positive quadratic regression model. The correlation between Zn concentrations on leaf tissues and AUBSPC was positive and significant (r = 0.68, P < 0.05). The results from this study showed that high foliar concentration of Zn was associated with increasing rice susceptibility to brown spot.     

Suppression of Rust and Brown Eye Spot Diseases on Coffee by Phosphites and By‐products of Coffee and Citrus Industries

The rust and brown eye spot, caused by Hemileia vastatrix and Cercospora coffeicola, respectively, are the most important fungal diseases on coffee in South America. Their management is mainly by chemical treatment, and there is no genetic resistance to brown eye spot known so far. Considering the need for developing alternative products for their control, the goal of this work was to evaluate the effects of phosphites and by‐products of coffee and citrus industries on rust and brown eye spot. Formulations of coffee and citrus industry by‐products, phosphites and their combination with fungicide were evaluated in field experiments, and their effect on fungal urediniospores and conidia was evaluated in vitro. In the field, treatments were applied individually or in combination and the in vitro assays were performed with manganese phosphite (Reforce Mn), potassium phosphite and citrus industry by‐product (Fortaleza), copper phosphite and coffee industry by‐product (Fitoforce Full), and fungicide. The severity and incidence of rust and brown eye spot on coffee leaves, yield, and leaf retention were evaluated in the field. Percentage of spore germination was evaluated in vitro for both fungi, whereas mycelial growth was evaluated for C. coffeicola only. The treatments Fortaleza, Reforce Mn and Fitoforce Full suppressed both diseases with a reduction in defoliation. In the year 2012, the plants treated with Reforce Mn and Reforce Mn + Fortaleza showed a yield increase of 72 and 88%, respectively, which was similar to the results shown by the fungicide treatment. In vitro inhibition of germination of H. vastatrix urediniospores and of C. coffeicola conidia was observed and suggests that the products exert some toxic effects to both fungi. Finally, the results observed indicate that the combined use of by‐products of plant‐processing industries and phosphites is an alternative and can be added efficiently to the management of coffee diseases.     

First Report of Pseudomonas lurida Causing Bacterial Leaf Spot on Miscanthus sinensis

Miscanthus spp. are large perennial wetland grasses that are receiving considerable attention as bioenergy crops. In late summer 2011, leaf spot symptoms were observed in a field of Miscanthus sinensis in Jeongseon, Gangwon province, Korea. Bacterial strains that belonged to the γ‐Proteobacteria genus Pseudomonas were isolated from the affected leaves. By phylogenetic analysis and phenotypic characterization, the representative strain MDM‐03 was identified as Pseudomonas lurida. Healthy M. sinensis leaves inoculated with MDM‐03 developed leaf spots similar to those observed in field. Bacteria re‐isolated from the leaf lesions were identical to the original strain MDM‐03 based on their cultural characteristics and 16S rDNA sequencing. This is the first report of bacterial leaf spot in Miscanthus sinensis.     

First report of Bipolaris bicolor causing a leaf spot disease on rubber tree

The rubber tree (Hevea brasiliensis) is the only resource for commercial natural rubber production and thus has economic importance in Southeast Asia. A spot disease on the leaves of a rubber tree was first discovered in 2017 in Hainan, China. In this study, the fungal isolate MA1 from the infected tissues was determined to be a pathogen of the spot disease by satisfying Koch's postulates. The isolate MA1 was identified as Bipolaris bicolor based on the morphological characteristics and multigene phylogenetic analysis. Among fungicides, prochloraz, iprodione and pyraclostrobin significantly inhibited hyphal growth of B. bicolor under in vitro conditions. This study constitutes the first report on the association of B. bicolor with leaf spot disease of rubber trees worldwide.     

Evidence of Alternaria alternata Causing Leaf Spot of Aloe vera in Iran

A leaf spot and leaf blight disease was observed on Aloe vera plants as small, circular to oval dark brown necrotic sunken spots on leaves. Infected tissues collected from different sites in diseased fields were cultured on potato carrot agar medium, and the pathogen was identified as Alternaria alternata on the basis of morphological and cultural characteristics. The conidiophores were branched, straight, golden brown, smooth‐walled, measuring up to μm long by 3 μm wide with one conidial scar. The conidia were golden brown in colour and produced in long branched chains, obclavate in shape and in short conical flask. Pathogenicity tests conducted on healthy potted aloe plants in a glasshouse showed typical leaf spot symptoms after 4–7 days. The optimal temperature for the growth of A. alternata was 25°C.     

First report of Alternaria leaf spot caused by Alternaria alternata (Fries.) Kiessler on Sonchus oleraceus L. and Convolvulus arvensis L. in Algeria

Alternaria leaf spot caused by Alternaria alternata (Fries.) Kiessler was found on sow thistle (Sonchus oleraceus L.) and field bindweed (Convolvulus arvensis L.) in the experimental station of ENSA (Ecole Nationale Supérieure d'Agronomie) in Algiers, Algeria, during the winter of 2016. Necrotic spots in the form of concentric circles were observed on the leaves of both weeds with disease incidence of approximately 70% and disease severity ranging from 50% to 70%. Fungi were isolated from the infected leaves and identified as A. alternata, based on morphological and molecular analyses (using genetic marker internal transcribed spacer, ITS of rDNA). Pathogenicity tests confirmed that A. alternata is the causing agent of leaf spot disease of sow thistle and field bindweed in accordance with the original symptoms. To the best of our knowledge, this is the first report of sow thistle and field bindweed naturally infected by A. alternata in Algeria.     

Identification and Characterization of two new Fungal Pathogens of Polygonatum odoratum (Angular Solomon's seal) in Italy

Polygonatum odoratum (Mill.) Druce (Angular Solomon's seal) is a well‐known ornamental plant and herbal drug, which is used in traditional medicine. Severe leaf spots were observed in wild Angular Solomon's seal plants in a public park in Trento, Italy. A combination of morphological and molecular characteristics, including sequence data of ITS‐rDNA, large subunit (LSU), beta tubulin (TUB) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) led to identification of two species, namely Phoma odoratissimi and Colletotrichum dematium s. str., isolated from these leaf spots. Pathogenicity of the isolates was confirmed on wounded leaves of Po. odoratum; indeed, both species induced leaf spot symptoms on inoculated leaves within 10 days of inoculation. This is the first report of leaf spot disease caused by Ph. odoratissimi and C. dematium s. str. on Po. odoratum, which can be considered a new host for both the species examined in this study. In addition, isolation of Ph. odoratissimi represents a new record for the mycobiota of Italy.     

Morphological and molecular identification of Colletotrichum siamense,a novel leaf pathogen associated with Sterculia lanceolata recorded in China

Sterculia lanceolata, an important tropical woody plant, has high ornamental and medicinal value. To our knowledge, only brown root disease in this plant has been reported. In Nanning, Guangxi, China, an outbreak of leaf blight disease was observed on S. lanceolata in June 2019, with the leaf infection rate ranging from 80% to 100%. The disease seriously affected the leaves of trees and caused economic loss. Eight isolates were recovered from the infected leaves of different trees, and the pathogenicity was then determined by the methods of mycelial disc and conidial suspension, fulfilling Koch's postulates. According to the morphological and molecular biological characteristics of isolates, the pathogen causing leaf blight on S. lanceolata was identified as Colletotrichum siamense. Accurate identification of the pathogen provides a reliable basis for the control of the disease.     

Investigating variability and behaviour of Colletotrichum gloeosporioides strains from lesions of coffee blister spot

Coffee blister spot has been associated with species from the Colletotrichum genus, but there is no information on the variability of isolates present on leaf lesions. This study evaluated a population of Colletotrichum gloeosporioides strains from blister spot lesions in Coffea arabica. Colletotrichum spp. isolates were collected from blister spot lesions on leaves of coffee trees from Catuaí and Topázio cultivars (Coffea arabica). Monosporic cultures were obtained from colonies with sporulation. A pathogenicity test was carried out by inoculation of pathogens on the leaves of young coffee plants. C. gloeosporioides strains were characterized by morphologial, cytological and physiological analyses. The molecular analysis was carried out using Inter‐Retrotransposon Amplified Polymorphism (IRAP) markers. C. gloeosporioides strains showed no pathogenicity on coffee plants and presented a wide variability in all traits evaluated. The presence of sexual strains, formation of CATs (conidial anastomosis tubes) among conidial strains and high mycelial compatibility among strains observed suggest the occurrence of sexual and asexual recombination. The role of these C. gloeosporioides strains on the lesions of coffee plant leaves is unclear.     

Zonate Leaf Spot of Prunus mandshurica Caused by Hinomyces pruni in Korea

Zonate leaf spots and severe defoliation were observed on Manchurian apricot (Prunus mandshurica) growing in a humid location in Korea from 2011 through 2013. The main symptoms included greyish green to brownish grey and zonate leaf spots without border lines, which mostly led to premature defoliation. The morphological characteristics of the causal agent were consistent with Hinomyces pruni. Identification was supported by analysing the sequence of the internal transcribed spacer region of ribosomal DNA from an isolate. The pathogenicity of the isolate was confirmed by artificial inoculation. This is the first report of zonate leaf spot caused by H. pruni on Manchurian apricot globally as well as in Korea.     

Identification and Characterization of Pseudocercospora Species Causing Grapevine Leaf Spot in China

Pseudocercospora is an important plant pathogenic genus causing leaf spots on grapevine leaves and other hosts worldwide. A survey of vineyards in four provinces of China was carried out to identify the causal agent of Pseudocercospora leaf spot. A phylogenetic analysis based on a combination of LSU, ITS and ACT loci, coupled with morphology, showed that Pseudocercospora vitis is the sole causal agent of this leaf spot disease. This study represents the first attempt to identify and characterize the cercosporoid species causing Pseudocercospora leaf spot in China using morphological and molecular approaches.     

Molecular identification and characterization of Elsinoë murrayae (Synonym: Sphaceloma murrayae) from weeping willow

Sphaceloma murrayae is a significant fungal pathogen of Salix spp. It causes greyish‐white leaf spots, which were reported worldwide except in China. Its morphological characteristics were described in the early literature; however, there is a lack of molecular information pertaining to this fungus. This study identified and characterized three fungal isolates that obtained from weeping willow leaf spots in China. Based on disease symptoms, morphological characteristics and single nomenclature rules for fungi, these isolates are proposed to be new combinations of Elsinoë murrayae (Synonym: S. murrayae). Phylogenetic analysis that combined internal transcribed spacer (ITS), large subunit (LSU), RBP2 and TEF1‐α DNA sequences indicated that E. murrayae isolates and Elsinoë salicina—another Elsinoë sp. isolated from Salix sp.—were distinguishable species. With trypan blue staining and stereomicroscopic observation, we found that large‐scale cell death occurred at 2 days postinoculation (dpi) and slight disease symptoms started at 3 dpi when the conidia were inoculated on Salix babylonica leaves. Pathogenicity analysis revealed that three isolates can successfully infect mature leaves of S. babylonica, Salix fragilis and Salix suchowensis, but not Salix matsudana. In addition, a necrosis‐ and ethylene‐inducing‐like proteins’ (NLP) gene, named EmNLP1, was cloned. The cytotoxicity of EmNLP1 was confirmed by transient assay in tobacco. During infection, EmNLP1 dramatically peaked at 2 dpi and maintained a high‐level expression in the necrosis lesion growing stage.     

Distribution of the black pecan aphid,Melanocallis caryaefoliae,on the upper and lower surface of pecan foliage

Three aphid species regularly feed on pecan [Carya illinoinensis (Wangenh.) K. Koch (Juglandaceae)] foliage: the black pecan aphid, Melanocallis caryaefoliae (Davis), the yellow pecan aphid, Monelliopsis pecanis Bissell, and the blackmargined aphid, Monellia caryella (Fitch) (all Hemiptera: Aphididae). Adults of M. caryaefoliae and both the nymphs and adults of M. pecanis and M. caryella mainly feed on the lower surface of leaves. Nymphs of M. caryaefoliae appear unique by frequently feeding on the upper surface of pecan leaves. This is risky behavior given the environmental hazards (e.g., rain, solar radiation, and dislodgement) associated with the upper surface. Thus, we determined the leaf surface distribution of M. caryaefoliae on trees in an orchard and on pecan seedlings in the laboratory. A pecan orchard survey found all three aphid species and stages predominantly on the lower leaf surface, except for the nymphs of M. caryaefoliae, which were evenly distributed between upper and lower leaf surfaces. This survey also found aphidophagous lacewing (Neuroptera) larvae predominantly on the lower leaf surface, whereas ladybird beetle (Coleoptera: Coccinellidae) larvae were more evenly distributed between upper and lower surfaces. Laboratory experiments using single or multiple pecan aphid species revealed M. caryaefoliae distribution on pecan seedlings similar to orchard data. Nymphal M. caryaefoliae require nearly 2 days to elicit chlorotic feeding lesions on leaves; without these lesions, nymphal development is hindered. The similar distribution of nymphs of M. caryaefoliae on both leaf surfaces likely reflects a strategy of predator avoidance allowing a proportion of the population to survive.