Jul 2026· CTU Journal of Innovation and Sustainable Development· 0 citations· 7 references
TL;DR
Results indicate that CLSD in Viet Nam is associated with a pathogen complex in which C. siamense is more pathogenic than P. microspora, while C. siamense grew most rapidly on potato-based media at 25–30°C.
Abstract
Circular leaf spot disease (CLSD) has recently emerged as an important foliar disease of rubber (Hevea brasiliensis) in Viet Nam, yet information on its associated pathogens remains limited. This study investigated the biological characteristics and pathogenicity of Pestalotiopsis microspora and Colletotrichum siamense associated with CLSD. Sixteen isolates of each species were obtained from diseased leaves collected in major rubber-growing regions of Viet Nam. Morphological characteristics were evaluated on different culture media and temperature regimes, while pathogenicity was assessed under laboratory and greenhouse conditions and confirmed through Koch’s postulates. Pestalotiopsis microspora showed optimal growth on malt extract agar at 25°C, whereas C. siamense grew most rapidly on potato-based media at 25–30°C. ITS sequence analysis showed ≥99% similarity between all isolates and reference sequences of P. microspora and C. siamense in GenBank. Disease severity index values on detached leaves ranged from 34.4–52.1% for P. microspora, 54.5–99.8% for C. siamense, and 92.0–100% for mixed inoculations (ANOVA, p < 0.01). Greenhouse inoculations showed a similar pattern. Among six rubber clones, RRIV 124 was the most susceptible under laboratory conditions. These results indicate that CLSD in Viet Nam is associated with a pathogen complex in which C. siamense is more pathogenic than P. microspora, while...
The findings provide a theoretical foundation for accurate disease diagnosis, epidemiological surveillance, and the development of effective chemical control strategies for rubber plantations.
Zhiying Cai, Lili He, Li-Ming Dai et al.· Plants· 0 citations
In vitro fungicide sensitivity assays, performed using the hyphal growth inhibition method against six common fungicides, demonstrated that Carbendazim was the most effective agent, indicating significant selectivity.
Fang Wu, Jing Tu, Zhu-xiang Liu et al.· Plant Disease· 0 citations
Amomum villosum is an evergreen perennial herb widely distributed in tropical and subtropical regions, with significant economic and medicinal importance. Throughout the cultivation process, it faces severe fungal disease problems that significantly impact its yield and quality. In July 2025, leaf spot disease with a 56% incidence was observed on A. villosum in Wenshan, Yunnan, China. Affected leaves initially developed irregular grayish-white lesions surrounded by brown margins. As symptom development progressed, semi-submerged black spots formed on the lesion surfaces. Severe infections resulted in premature leaf abscission and, ultimately, death of the entire plant. To identify the pathogen responsible, we conducted isolation and pathogenicity studies. Through morphological characterization, phylogenetic analysis (ITS, LSU, and TUB), and pathogenicity tests, Pestalotiopsis microspora was determined as a pathogen. Koch’s postulates were fulfilled on attached leaves. After 15 days, typical necrotic lesions appeared on inoculated leaves, while controls remained symptom-free. This is the first report of A. villosum leaf spot caused by P. microspora in China. Biocontrol assays revealed that Trichoderma harzianum T15 and T. asperellum T16 exhibited significant antagonistic activity against P. microspora, with inhibition rates of 44.77% and 50.70%, respectively. In addition, Bacillus velezensis SWFU41, isolated from healthy A. villosum leaves, showed superior disease suppression, achieving a control efficacy of 60.52%. Compared with the fungal biocontrol agents, B. velezensis demonstrated greater inhibitory activity against the pathogen, suggesting that bacterial antagonists may provide a more effective biological control strategy for managing A. villosum leaf spot disease. This is the first report of P. microspora-caused leaf spot disease on A. villosum. Furthermore, the comparative evaluation of fungal and bacterial antagonists demonstrated that B. velezensis SWFU41 outperformed T. harzianum and T. asperellum in disease suppression, highlighting its potential as a promising biocontrol agent for sustainable disease management. These findings provide a scientific basis for pathogen monitoring, epidemiological studies, and the development of integrated biological control strategies for A. villosum cultivation.
Namchul Pu, Rui Wang, Wan-Shan Shao et al.· Journal of Fungi· 0 citations
Leaf spot diseases represent a major constraint to eggplant production under favourable environmental conditions. Therefore, potential pathogenicity of the fungus Cladosporium uredinicola on the leaves of eggplant (Solanum melongena L.), cultivar 'Barcelona F1', was confirmed in this study. Symptomatic leaf tissues were obtained from several greenhouse locations in Basrah governorate, southern Iraq. The first isolation of the fungus was done on potato dextrose agar (PDA) plates, followed by the investigation of morphological and microscopic features. Cladosporium uredinicola fungal growth on the PDA medium was olive-green to dark olivaceous-brown pigmentation and irregular margins, while the microscope conidiophores were light to medium olive colorin colour, smooth to finely roughened, bearing short terminal chains of 2–5 conidia. Pale olivaceous-brown, ellipsoid to oblong in shape, smooth-walled conidia were observed with 0–3 transverse septa. The internal transcribed spacer (ITS) region was targeted for confirming the identification; the ITS sequence was deposited in the National Center for Biotechnology Information (NCBI) GenBank database under accession number PV961371.1. Pathogenicity trials were followed under greenhouse conditions, revealing the pathogenic effect of C. uredinicola on eggplant leaves, showing necrotic lesion symptoms, which initially appeared after five days post-inoculation as small brown, circular to irregular margins, subsequently extended and coalesced into large spots and patches with chlorosis symptoms and ended with leaf abscission. The fungal pathogen was re-isolated from diseased leaves to confirm Koch's postulates. The current study represents the first report of C. uredinicola as a potential pathogen on eggplant leaves in Iraq.
A. M. Angham, H. A. Mohammed· Plant Science Today· 0 citations
Cabbage (Brassica oleracea var. capitata) is one of the major winter vegetables grown in Bangladesh, recognized for its dietary value and economic importance. During November 2023, cabbage leaves exhibiting typical leaf spot symptoms were collected from the Bangladesh Agricultural Research Institute (BARI), Gazipur, to identify the associated pathogen. The infected leaves showed dark brown to black necrotic lesions with concentric rings characteristic of Alternaria leaf spot. The pathogen was isolated on Potato Dextrose Agar (PDA) and purified using a single-conidium isolation technique. Morphological characterization revealed colony and conidial features consistent with Alternaria alternata. To confirm the pathogen identity, molecular characterization was performed using the internal transcribed spacer (ITS) region of rDNA. Amplification with ITS1/ITS4 primers generated a 510 bp fragment, and the resulting sequence was deposited in GenBank under accession number OP585635. Comparison of the obtained sequence against the GenBank database revealed a high degree of homology (99%) with previously deposited A. alternata sequences. The phylogenetic tree also placed the isolate in the same evolutionary group as A. alternata, with 88% bootstrap support. Species-specific PCR using A. alternata-specific primers produced the expected 184 bp amplicon, providing additional confirmation of species identity. Pathogenicity was evaluated using a detached-leaf assay. Leaves inoculated with the fungal isolate exhibited characteristic disease symptoms comparable to those recorded in naturally infected plants, while no symptoms were detected on the control leaves. Following symptom development, the fungus was recovered from infected tissues and its identity was verified using an A. alternata-specific PCR assay, satisfying the requirements of Koch’s postulates. The combined evidence obtained from cultural and microscopic observations, ITS-rDNA sequencing, phylogenetic inference, species-specific molecular detection, and pathogenicity assessment demonstrated that A. alternata was responsible for the leaf spot symptoms observed on cabbage. To our knowledge, this study constitutes the first molecularly confirmed record of A. alternata infecting cabbage in Bangladesh. The information generated will support future disease monitoring efforts and contribute to the formulation of appropriate management practices for sustainable cabbage production.
Asian Australas. J. Food Saf. Secur. 2026, 10(2), 56-63
F. Elahi, M. M. Hasan, Monirul Islam et al.· Asian-Australasian journal o...· 0 citations
This study aimed to investigate the occurrence of chili anthracnose, characterize the associated pathogen, and evaluate the antifungal potential of plant-derived products as sustainable management options in the Muong Khuong area, Lao Cai province. Field investigations showed that anthracnose was prevalent on both hot chili and sweet chili, with disease incidences of 50.50% and 70.48%, respectively, during the July survey. Anthracnose symptoms were observed on leaves and fruits of chili types. The pathogen was isolated from symptomatic tissues and characterized based on colony morphology, microscopic features, pathogenicity tests, and ITS sequence analysis. Re-inoculation on detached chili leaves and fruits reproduced anthracnose symptoms, confirming the pathogenicity of the isolate. BLASTn analysis of the ITS region revealed 100% sequence identity with species within the Colletotrichum gloeosporioides species complex. In vitro antifungal assays demonstrated that extracts from Piper betle, Elsholtzia ciliata, and Ocimum basilicum inhibited the pathogen's mycelial growth. Among them, Piper betle showed the strongest inhibitory effect (62.16% inhibition at 5 days after treatment), followed by Elsholtzia ciliata (23.91% inhibition at 5 days after treatment) and Ocimum basilicum (15.68% inhibition at 3 days after treatment). These findings support the potential use of plant-derived products for sustainable management of chili anthracnose.
Ong Xuan-Phong, Nguyen Huy-Thinh, Ngo Thi-Thuong et al.· CTU Journal of Innovation an...· 0 citations
