scholarly journals First Report of Myrothecium verrucaria from Muskmelon Seeds

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 589-589 ◽  
Author(s):  
A. Belisario ◽  
E. Forti ◽  
L. Corazza ◽  
H. A. van Kesteren

Myrothecium verrucaria (Albertini & Schwein.) Ditmar:Fr. was isolated from muskmelon (Cucumis melo L.) seeds of Charentais-T, a culti var used as a differential host with no resistance to Fusarium oxysporum f. sp. melonis races. A white floccose mycelial mat developed on melon seeds during incubation on moist blotters. Mycelia were mass transferred from melon seeds onto potato dextrose agar (PDA) medium. At 25°C in the dark, a mycelial mat with characteristic annelations of greenish-black sporodochia, without setae, was produced. Conidia (2 to 3 × 6 to 10 μm) were lemon shaped, with a typical conical mucous appendage at one end, which was visible with Loeffer's flagella stain (1). Based on these characteristics, the fungus was identified as M. verrucaria. For pathogenicity studies, surface sterilized seeds of C. melo cv. Charentais-T were coated with M. verrucaria conidia by gently rubbing the seeds on sporodochia produced on 15-day-old cultures on PDA. Once coated, seeds were plated onto water agar and on sterile moist blotters in 9-cm-diameter petri dishes. Plates were incubated at 28°C in the dark. Five seeds per plate and three plates per experiment were used. Experiments were replicated three times. Control seeds were plated without coating. After 7 days, on water agar, 90% of melon seeds failed to germinate while the remaining 10% produced young seedlings that died from root rot and necrotic lesions on the hypocotyl. After 12 days on moist blotters, 100% of the melon seedlings died, showing necrotic lesions on the hypocotyl and on the main root. The pathogen was reisolated from symptomatic melon seedlings. All control seeds germinated and grew into healthy seedlings. M. verrucaria, known to be a seed-borne pathogen, has been isolated from soil and plants worldwide (2). This is the first report of M. verrucaria pathogen on muskmelon. This fungus is not a serious concern when seeds are dressed with fungicides. References: (1) K. V. A. Thompson and S. C. Simmens. Nature. 193:196, 1962. (2) S.-M. Yang and S. C. Jong. Plant Dis. 79:994, 1995.

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 313-313 ◽  
Author(s):  
A. M. Al-Sa'di ◽  
M. L. Deadman ◽  
F. A. Al-Said ◽  
I. Khan ◽  
M. Al-Azri ◽  
...  

Muskmelon (Cucumis melo L.) is one of the most important vegetable crops in Oman. In the fall of 2004, sudden wilt was observed in muskmelon grown in a field at Sultan Qaboos University, Muscat. The disease was characterized by rapid collapse of vines and muskmelon plants at the fruit production to maturation stage, associated with brown-to-dark brown rotted primary and secondary roots. The disease resulted in death of more than 85% of muskmelon plants in that field. On potato dextrose agar (PDA), with published methods (1), Pythium spp. were consistently isolated from crowns and roots of plants showing wilt symptoms. Further identification of five isolates of Pythium with sequences of the internal transcribed spacer (ITS) of the ribosomal DNA (1) using ITS1 and ITS4 primers produced a nucleotide sequence 806 bp long, which was identical among all isolates. Comparison with sequences deposited at the National Center for Biotechnology Information revealed 100% nucleotide similarity to a previously published sequence (Accession No. DQ381808) of isolate P091 of P. splendens from cucumber from Oman, for which identification has also been confirmed by morphological characteristics. The sequence of one isolate of P. splendens (P222) was assigned GenBank Accession No. EF546436 and deposited at CBS under Accession No. CBS121855. In pathogenicity tests conducted in a greenhouse, P. splendens induced damping-off symptoms on 7-day-old muskmelon seedlings and also reproduced the same wilt symptoms observed in the field when 2-month-old muskmelon plants were inoculated with 3-day-old P. splendens grown in PDA. To our knowledge, this is the first report of association of P. splendens with wilt of muskmelon in Oman. Reference: (1) A. M. Al-Sa'di et al. Plant Pathol. 56:140, 2007.


BIOEDUSCIENCE ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 1-10
Author(s):  
Muhammad Alif Ishak ◽  
Budi Setiadi Daryono

Background: A powdery mildew-resistant cultivar of melon is needed to increase melon yield crops. Meloni is a superior melon cultivar bred through a crossing between ♀ SL-3 and ♂ PI 371795, resulted by the Laboratory of Genetics and Breeding, Faculty of Biology, UGM. This study aimed to determine the level resistance of Meloni to powdery mildew infection and to identify the powdery mildew species that infected Meloni based on morphological characters. Methods: Meloni seeds were germinated and planted in the greenhouse of PIAT UGM. Powdery mildew spores were inoculated into the leaves after ±2 weeks of age. Leaf infected were scored using the gridline every 3 days for 6 weeks. Scoring results were converted to the diseases index score. Furthermore, powdery mildew species was identified using morphological characters. Results: Meloni had a tolerance level of resistance to the powdery mildew infection. Based on the morphological characters with fibrosin bodies, conidia ovoid-shape and the position of the germ tube in the lateral part of the conidia, powdery mildew that infected Meloni was expected as P. xanthii. Conclusions: Meloni can be expected as an alternative to superior melon seeds resistant to pest and disease infections especially powdery mildew.  


Author(s):  
José L. Escobar-Álvarez ◽  
Omar Ramírez-Reynoso ◽  
Paulino Sánchez-Santillán ◽  
Rocío Cuellar-Olalde ◽  
Teolincacíhuatl Romero-Rosales ◽  
...  

Objective: To determine the physical and physiological characteristics of Creole melon seeds from the Costa Chica ofGuerrero.Design/Methodology/Approach: It was established under a completely randomized design, and Student’s t-tests (a=0.05) and correlation with Pearson’s test were performed. Viability and imbibition were carried out using the methodologies described by the International Seed Testing Association (ISTA).Results: Creole seeds of the two varieties presented a significant statistical difference (95% confidence level) in the physical quality variables. The imbibition ended at 18 and 32 h in V2 and V1, respectively, after being submerged in water. The humidity percentage was higher in V1 (7.19); while, V2 presented a higher percentage of germination and viability (96 and 90%, respectively). There is a positive association between the humidity and the physical dimensions of the seed and the germination and viability (r2=0.954) that is highly significant (P=0.003).Study Limitations/Implications: Morphological and taxonomic classification studies of the Creole genotypes of the Costa Chica region of Guerrero are required.Findings/Conclusions: There was a positive correlation between the physical and physiological quality of the Creole melon seeds.


Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 921-921
Author(s):  
M. Tomaso-Peterson ◽  
L. E. Trevathan ◽  
M. S. Gonzalez

Take-all root rot has been reported as a destructive disease of St. Augustinegrass home lawns in Florida and Alabama (1). In June 1998 and 1999, St. Augustinegrass home lawns in central Mississippi developed chlorotic, thinning patches ranging from 0.5 to 4.5 m in diameter. By August of each summer, plants within affected patches were necrotic and dead. Roots of affected St. Augustinegrass were necrotic and shorter than those of unaffected plants; nodes on stolons were necrotic, and lesions developed on internodes. Ectotrophic runner hyphae and dark brown, lobed hyphopodia were visible on roots and aboveground plant parts, respectively. Symptomatic tissues collected from St. Augustinegrass home lawns were plated onto potato dextrose agar (PDA); the incitant of take-all root rot, Gaeumannomyces graminis(Sacc.) Arx & Olivier var. graminis, was isolated. Verification of G. graminis var. graminis was based on colony morphology and taxonomic identification consistent with the description by Walker (2). G. graminis var. graminis isolated from symptomatic St. Augustinegrass was grown on sterile tall fescue seed and incorporated into sterile sand/peat moss mix. Asymptomatic St. Augustinegrass sprigs were washed, and roots were removed prior to planting in infested and noninfested soil. Plants were cultured in the greenhouse for 60 days. St. Augustinegrass planted into noninfested soil was asymptomatic while plants collected from G. graminis var. graminis-infested soil were symptomatic for take-all root rot. Crowns and roots of affected plants were necrotic; leaves were chlorotic and necrotic. Both runner hyphae and lobed hyphopodia were visible. G. graminis var. graminis was reisolated from symptomatic tissues and confirmed as the incitant of take-all root rot. This is the first report of take-all root rot of St. Augustinegrass in Mississippi. References: (1) M. Elliott. Plant Dis. 77:206, 1993. (2) J. Walker. Trans. Br. Mycol. Soc. 58:427, 1972.


Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 697-697
Author(s):  
M. L. Molinero-Ruiz ◽  
J. M. Melero-Vara

In 2001, sunflower (Helianthus annuus L.) plants with symptoms of stem and root rot and wilt were observed in Soria, Spain. Light brown, water-soaked lesions developed on the collar of infected plants and extended along the stem, affecting the pith and causing early and sudden wilt. White mycelium and sclerotia (0.5 to 2 mm long) formed in the pith of stems. The sclerotia were disinfested in NaClO (10% vol/vol) for 1 min, transferred to potato dextrose agar (PDA), and incubated at 20°C. The fungus consistently obtained was identified as Sclerotinia minor Jagger (1). Pathogenicity was confirmed in a greenhouse experiment (15 to 25°C, 13 h light). Seven-week-old plants of six genotypes of sunflower (‘Peredovik’, HA89, HA821, HA61, RHA274, and HA337) were inoculated by placing one PDA disk with active mycelial growth adjacent to each basal stem just below the soil line and covering it with peat/sand/silt (2:2:1, vol/vol). Six plants of each genotype were inoculated without wounding, and another six were inoculated immediately after stem base wounding with a scalpel; six wounded and uninoculated plants were used as controls. First symptoms (wilting) appeared 4 days after inoculation in all genotypes. Two weeks after inoculation, the percentage of dead plants ranged from 33 to 92% (depending on cultivar), white mycelium was observed at the base of affected plants, and sclerotia were present in the pith of diseased plants. There was no effect of plant wounding on disease incidence or severity, and the fungus was reisolated from inoculated plants. To our knowledge, this is the first report of S. minor in Spain. Reference: (1) L. M. Kohn. Mycotaxon IX 2:365, 1979.


Jurnal Agro ◽  
10.15575/6244 ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 42-51
Author(s):  
Achmad Amzeri ◽  
Kaswan Badami ◽  
Syaiful Khoiri ◽  
Ahmad Syaiful Umam ◽  
Nasirul Wahid ◽  
...  

Perakitan varietas melon hibrida dengan karakter-karaker unggul merupakan suatu upaya untuk memenuhi kebutuhan benih melon dalam negeri dan mengurangi ketergantungan impor benih melon dari luar negeri. Tujuan penelitian ini adalah untuk mengevaluasi penampilan fenotipik 24 genotip tanaman melon hibrida (F1).  Penelitian ini dilakukan di Kebun Percobaan Agroteknologi Fakultas Pertanian Universitas Trunojoyo Madura pada bulan Februari sampai Mei 2019. Bahan yang digunakan adalah 24 genotip melon hibrida (F1) hasil persilangan di antara galur-galur melon. Penelitian ini menggunakan Rancangan Acak Kelompok dengan satu perlakuan yaitu genotip dan diulang sebanyak 3 kali. Analisis data menggunakan analisis varians (Anova) yang dilanjutkan dengan uji Duncan pada taraf 5%. Nilai heritabilitas dalam arti luas dihitung menggunakan taksiran nilai kuadrat tengah pada analisis varians. Seleksi indeks digunakan untuk mendapatkan kandidat varietas tanaman melon hibrida. Hasil penelitian menunjukkan bahwa 24 tanaman melon hibrida (F1) yang diuji memiliki perbedaan penampilan pada karakter umur berbunga, panjang buah, diameter buah, tebal daging buah, kadar gula, jumlah biji per buah, bobot buah per tanaman dan produksi per hektar. Nilai heritabilitas dalam arti luas tanaman melon hibrida (F1) pada karakter yang dievaluasi berkisar antara 0,15 – 0,71. Hasil  nilai seleksi indeks terboboti menunjukkan bahwa terdapat dua calon varietas tanaman melon hibrida yang memiliki seleksi indeks tertinggi yaitu G4 dan G5.  ABSTRACTAssembling hybrid melon varieties with superior characters is an effort to meet the needs of domestic melon seeds and reduce dependence on imported melon seeds. The purpose of this study was to evaluate the phenotypic appearance of 24 genotypes of hybrid melon plants (F1).  This research was conducted at the Agrotechnology Experimental Field at Faculty of Agriculture, Universitas Trunojoyo Madura from February to May 2019. The materials used


Plant Disease ◽  
2020 ◽  
Author(s):  
Siti Izera Ismail ◽  
Nur Ainina Noor Asha ◽  
Dzarifah Zulperi

Rockmelon, (Cucumis melo L.) is an economically important crop cultivated in Malaysia. In October 2019, severe leaf spot symptoms with a disease incidence of 40% were observed on the leaves of rockmelon cv. Golden Champion at Faculty of Agriculture, Universiti Putra Malaysia (UPM). Symptoms appeared as brown necrotic spots, 10 to 30 mm in diameter, with spots surrounded by chlorotic halos. Pieces (5 x 5 mm) of diseased tissue were sterilized with 0.5% NaOCl for 1 min, rinsed three times with sterile distilled water, plated onto potato dextrose agar (PDA) and incubated at 25°C for 7 days with a 12-h photoperiod. Nine morphologically similar isolates were obtained by using single spore isolation technique and a representative isolate B was characterized further. Colonies were abundant, whitish aerial mycelium with orange pigmentation. The isolates produced macroconidia with 5 to 6 septa, a tapered with pronounced dorsiventral curvature and measured 25 to 30 μm long x 3 to 5 μm wide. Microconidia produced after 12 days of incubation were single-celled, hyaline, ovoid, nonseptate, and 1.0 to 3.0 × 4.0 to 10.0 µm. Morphological characteristics of the isolates were similar to the taxonomic description of Fusarium equiseti (Leslie and Summerell 2006). Genomic DNA was extracted from fresh mycelium using DNeasy Plant Mini kit (Qiagen, USA). To confirm the identity of the fungus, two sets of primers, ITS4/ITS5 (White et al. 1990) and TEF1-α, EF1-728F/EF1-986R (Carbone and Kohn 1999) were used to amplify complete internal transcribed spacer (ITS) and partial translation elongation factor 1-alpha (TEF1-α) genes, respectively. BLASTn search in the NCBI database using ITS and TEF-1α sequences revealed 99 to 100% similarities with species of both F. incarnatum and F. equiseti. BLAST analysis of these in FUSARIUM-ID database showed 100% and 99% similarity with Fusarium incarnatum-F. equiseti species complex (FIESC) (NRRL34059 [EF-1α] and NRRL43619 [ITS]) respectively (Geiser et al. 2004). The ITS and TEF1-α sequences were deposited in GenBank (MT515832 and MT550682). The isolate was identified as F. equiseti, which belongs to the FIESC based on morphological and molecular characteristics. Pathogenicity was conducted on five healthy leaves of 1-month-old rockmelon cv. Golden Champion grown in 5 plastic pots filled with sterile peat moss. The leaves were surface-sterilized with 70% ethanol and rinsed twice with sterile-distilled water. Then, the leaves were wounded using 34-mm-diameter florist pin frog and inoculated by pipetting 20-μl conidial suspension (1 × 106 conidia/ml) of 7-day-old culture of isolate B onto the wound sites. Control leaves were inoculated with sterile-distilled water only. The inoculated plants were covered with plastic bags for 5 days and maintained in a greenhouse at 25 °C, 90% relative humidity with a photoperiod of 12-h. After 7 days, inoculated leaves developed necrotic lesions similar to the symptoms observed in the field while the control treatment remained asymptomatic. The fungus was reisolated from the infected leaves and was morphologically identical to the original isolate. F. equiseti was previously reported causing fruit rot of watermelon in Georgia (Li and Ji 2015) and China (Li et al. 2018). This pathogen could cause serious damage to established rockmelon as it can spread rapidly in the field. To our knowledge, this is the first report of a member of the Fusarium incarnatum-F.equiseti species complex causing leaf spot on Cucumis melo in Malaysia.


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