During September of 2020, Fruit suspected to be rot were observed on Choerospondias axillaris grown in an plantation in Yichun, Jiangxi, China. Approximately 10
Medicinal plants have been used since the dawn of human civilization and over the years have gained attention in the academic community due to their use beyond folk medicine. Numerous plants make up recipes to suppress symptoms of various illnesses, with emphasis on plants of the genus Plectranthus and their antimicrobial properties. In July 2016, P. ornatus plants observed in a garden located in Recife, Pernambuco state, Brazil, which demonstrated symptoms of dry stem rot. Two fungi isolated from stem lesions were identified by morphological comparisons and combined DNA sequences as Lasiodiplodia theobromae. This is the first report of this pathogen in this medicinal plant in the world.
Brown circular stem canker symptom was observed on common bean plants in Mahallat county, Markazi province, Iran, in the summer of 2022. Five identical associated fungal isolates were recovered from the infected plants. Morphological and molecular characterization of the representative isolate (UTR38) using the partial sequence of beta-tubulin, and as well as RNA polymerase II second largest subunit loci was done. The associated fungus was identified as Paramyrothecium roridum. Pathogenicity of the isolate UTR38 was conducted on six-week-old seedling stems of the P. vulgaris cultivar Sunray. The inoculated fungus was also reisolated from the inoculated plants to fulfill the Koch’s postulates. According to the results, this is the first report of P. roridum as the causal agent of stem canker disease in P. vulgaris in Iran and worldwide.
During routine field surveys in February 2023, in a commercial field located in Hegazah village, Qus, Qena governorate, Egypt (25°50’49"N 32°49’33"E), powdery mildew symptoms were observed on leaves of a local cultivar of fenugreek (Trigonella foenum-graecum L.). Microscopic characterization showed that conidiophores were cylindrical, hyaline, straight, erect to bent, forming conidia singly, primary conidia were apically narrowed, lanceolate, obtuse to pointed measuring, secondary conidia were ellipsoid or cylindrical, measuring. Germ tubes were close to the base. BLASTn results showed 100
Capsicum (Capsicum annum var. grossum Sendt.) is a popular and widely cultivated vegetable crop. The leaves showing white to grey irregular spots were collected. The organism was isolated and cultured on potato dextrose agar from the diseased samples. The pathogenicity was proved on capsicum seedlings by inoculating hyphal suspension of the organism and koch’s postulates were proved by re-isolating the pathogen. The pathogen was identified as Stemphylium lycopersici based on morphological, cultural and molecular investigation (ITS, gapdh and cmdA). This is the first report of Stemphylium lycopersici causing leaf spot of capsicum in India.
Zinnia elegans of Family Asteraceae is a flowering plant grown widely in gardens in Indonesia. The plant is also often integrated into pest management of different agricultural commodities as its colourful flowers may attract beneficial insects including natural enemies. A total of eight viral symptomatic and four non-symptomatic Z. elegans samples were collected from four districts in Kulon Progo and Sleman Regencies of Special Region of Yogyakarta. They were molecularly tested using two universal primer pairs for begomoviruses, and two specific primer pairs for cucumber mosaic virus (CMV, Cucumovirus) detections. The eight symptomatic samples were all positive for CMV but negative for begomoviruses infections. The four non-symptomatic samples were tested negative to begomoviruses and CMV. Partial RNA2 and RNA3 segments of four CMV isolates were sequenced to demonstrate that they are members of subgroup IB. 4Ze-Ngaglik isolate was shown to be mechanically transmitted to healthy Z. elegans and cucumber cv. Baresta (Cucumis sativus). To the best of our knowledge, this report confirmed the first CMV occurrence in Z. elegans in Indonesia.
Bacterial soft rots are among the most economically important diseases that cause significant yield losses in various crops. During 2022 and 2023, widespread occurrence of soft rot disease was observed in sugar beet fields in the Firuzan region, Hamedan Province, Iran. From the sugar beet plants with soft rot symptoms, a bacterial isolate was obtained that was obligately aerobic, negative for Gram, oxidase, levan, and arginine dihydrolase tests, and positive for pectinase, urease and hypersensitivity reaction on tobacco. Koch’s postulates confirmed its pathogenicity by developing soft rot symptoms in sugar beet plants. The 16SrRNA and rpoD sequences from this isolate were most closely related to Pseudomonas punonensis LMT03 with 99.8
Orchids are among the most cultivated flowers in the world. Plants of Dendrobium thyrsiflorum (DT) and Cattleya wittigiana (CW), cultivated at the Botanic Garden of Bauru in São Paulo, Brazil, presented black rot symptoms. The causal organism was identified as P. palmivora on DT and P. nicotianae on CW orchids based on its morphological and molecular characterization. Inoculation caused disease symptoms and Koch’s postulates were fulfilled by re-isolation of the pathogen.
Papaya trees showing disease symptoms caused by root-knot nematodes (Meloidogyne spp.) were detected in a tropical fruit farm in Vero Beach, FL, USA. Roots were severely galled containing a high population density of root-knot nematode eggs. The nematode species causing damage was identified as M. incognita based on the morphometrics of body, stylet, and tail length of the second-stage juveniles, and morphological characteristics of female perineal patterns. Molecular analyses using both species-specific and universal primers also confirmed the species identity. A pathogenicity test confirmed M. incognita reproduction on papaya by producing nematode females and egg masses within the root galls. This report documents the first confirmed detection of M. incognita in papaya in Florida, USA, providing detailed information on the nematode's morphology characteristics and DNA sequence data.
Sri Lankan cassava mosaic virus (SLCMV) is one of the viruses that cause cassava mosaic disease. Strong mosaic symptoms on a cassava plant in the Northern Territory tested positive in begomovirus specific PCR testing. The DNA sequence of the amplicon was 96.38
Severe infection of stem rot was observed on plants of Withania somnifera during January and February of 2020 and 2021. Initial symptoms appeared on the plants showing paleness at infected areas, cottony, fluffy white mycelia was observed on the leaves, stem and inflorescence. In advanced stage of infection wilting of stem and defoliation was observed leading to partial or whole plant death. Based on its morphological and molecular traits, the fungus was identified as Sclerotinia sclerotiorum. Pathogenicity test was performed under controlled conditions resulting in similar symptoms to those observed in field. To the best of our knowledge, this is the worldwide first evidence of S. sclerotiorum causing stem rot disease on W. somnifera.
Trachyspermum ammi is a traditional medicinal plant and is widely used for curing various diseases in humans. During a 2022 survey, yellowing symptoms associated with phytoplasma disease were observed in Bhopal. The disease was detected by direct and nested PCR using phytoplasma-specific primers in symptomatic plant leaf samples. The suspected ~ 1.2 kb amplified amplicons were sequenced and submitted in GenBank under accession number OQ216747. The phytoplasma isolate showed the highest 99.42% sequence identity and phylogenetic relationships with the 16 S ribosomal RNA gene of an isolate of aster yellows phytoplasma ( ‘Candidatus Phytoplasma asteris’; 16SrI group). This is the first report of ‘Ca. P. asteris’ (16SrI) associated with the yellows disease of T. ammi.
Crocus sativus L. leaf samples were serologically tested for the presence of beet western yellows virus (BWYV) and 17.6
Lisianthus ( Eustoma russellianum ) is one of the emerging cut flower crops in international flower market quickly ranked in top ten cut flowers worldwide. Despite its rising popularity, studies relating to the identification and characterization of viral diseases affecting it are lacking from India. Thus, the present study was focused on identification and characterization of virus in lisianthus plants samples collected from Vensai Floritech, Narasihmanahalli village, Tubagere hobli, Doddaballapur taluk, Bengaluru rural district, Karnataka state, India exhibiting symptoms similar to begomoviruses infections. Association of the begomovirus with sample was confirmed by PCR using begomovirus specific primers which resulted in the expected amplicon (~ 1.2 kb). Further, whole-genome amplification was done by rolling circle amplification (RCA) for one representative sample (LIS-1). The amplified RCA product was cloned, sequenced and analyzed. The phylogenetic and nucleotide (nt) sequence analysis revealed that the begomovirus associated with lisianthus plants showed the maximum nt identity of 91.0% with sida yellow vein Madurai virus (SIYVMV-TN:OM141480) infecting a weed, Sida cordata , reported from Tamil Nadu, India, which is geographically close to Karnataka. Based on species demarcation criteria for begomoviruses, the collected isolate is identified as a strain of sida yellow vein Madurai virus associated with leaf curl of lisianthus from India and proposed the name “Sida yellow vein Madurai virus -[India:Karnataka:Doddaballapura:Lisianthus:2023]” and designated as SIYVMV-[IN:Kar:Dod:Lis:23]. Further, recombination analysis revealed a single intra-specific recombination event in the genomic region. Hence, this study provides a one more evidence of expanding host range for begomoviruses in India.
In Mexico, manzano pepper (Capsicum pubescens) is a crop of economic importance. In 2022, in the municipality of Taxco de Alarcon, Guerrero, Mexico, leaf spots were observed in the mazano pepper crop. The fungus Alternaria spp., was consistently isolated from symptomatic leaf of manzano pepper. A molecular characterization was carried out by amplification and sequencing of the internal transcribed spacer (ITS) region of ribosomal DNA, major allergen (Alt a 1), and anonymous gene region (OPA10-2). BLAST analysis indicated similarity that varied from 99.5 to 100% with Alternaria arborescens sequences in GenBank. A phylogenetic analysis was carried out using the Maximum Likelihood method of two isolates of Alternaria sp., obtained from manzano pepper, and indicated that they were clustered with A. arborescens sequences (CBS 115189 and CBS 112749). Using uninjured two month-old plants grown in greenhouse conditions, Koch's postulates were verified and fulfilled. To our knowledge, this is the first report of Alternaria arborescens as a caused leaf spot in manzano pepper in Mexico and in the world.
The Malayan apple is a tropical fruit known by various names, such as red guava and Malay rose apple. Originating in Southeast Asia, it has shifted from being an ornamental tree to being cultivated in India to meet global demand. Well-known for its health benefits, the fruit is rich in vitamins, minerals, and antioxidants. In May 2023, Malayan apple trees in Karnataka, India, displayed anthracnose symptoms, with a 20–25
Downy mildew is a production limiting factor for Brazil's main onion producing region. In the present study we adopted two management strategies (resistant cultivar and disease alert system) with the aim of reducing the number of systemic fungicide sprays, maintaining satisfactory yield levels. By carrying out fungicide sprays only when the alert system indicated a severe risk and using the cultivar “SCS379 Robusta”, it was possible to reduce the number of sprays from 11 (calendar) to 5 (alert system), maintaining statistically similar yields (32.58 ton./ha – calendar; and 30.76 ton/ha – alert system). Furthermore, considering only the value of the fungicide, the production cost was BRL 0.069/Kg – calendar, and BRL 0.033/Kg – alert system. Integrated management, using different control strategies, appears to be a viable alternative to mitigate the damage caused by onion downy mildew.
A new leaf blight disease in Schleichera oleosa seedlings was detected in a Kerala state forest nursery, India. Through morphological, cultural characterization, and multi-gene phylogenetic analysis, the fungal pathogen was identified as Pseudopestalotiopsis camelliae-sinensis, the first report on Schleichera in India. Koch’s postulates were fulfilled. Research attention is required to manage emerging seedling diseases for quality planting materials.
Basil (Ocimum basilicum) is an important aromatic and medicinal plant and is extensively cultivated for essential oil production. During the growing season of 2021–22, Sclerotinia stem rot has consistently been observed on basil at the Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar, India. Cottony, white mycelium and large, black sclerotia were observed on brown lesions on the stems and leaves of infected plants. The causal organism was identified as Sclerotinia sclerotiorum based on its morphological and molecular characterization.
In 2020, leaf spots were observed on Datura innoxia plants in Curitiba, Brazil. Alternaria alternata was identified after isolation from symptomatic leaves through morphological characterization, along with sequencing of the partial tef, gapdh , and rpb2 genes and phylogenetic analysis. Pathogenicity was proven using Koch’s Postulates. This is the first report of this species causing disease in Datura spp. worldwide.
